Posts Tagged ‘autologous transplant’


Leaders in the CAR-T Field Are Proceeding With Cautious Hope

Reporter: Stephen J. Williams, Ph.D.

It wasn’t a long time ago, in fact the May 26, 2014 Cover Story in Forbes entitled “Is This How We’ll Cure Cancer” with cover photo of Novartis CEO Joseph Jimenez and subtitle “Will This man Cure Cancer?” highlighted the promise of CAR-T therapy as the ‘magic bullet’ therapy which will eventually cure all cancer. However, over the years, the pioneers of such therapy, while offering impressive clinical results, caution not to get to eager in calling CAR-T as the end-all-be-all cure but insist there are many issues that need be resolved.

The Allogenic Approach

In an interview for LabBiotech.eu Phillip Hemme had a discussion (and wonderful writeup) with André Choulika, the CEO of the French CAR-T miracle Cellectis on the current state of CAR-T therapy for cancer. Below is the interview in full as ther ae multiple important point Dr. Choulika mentioned, including how much is needed to be done in the field.

Cellectis’ CEO: “I’m just trying to be realistic, CAR-T is not THE miracle cure for Cancer”




CAR-T is solidifying in everybody’s mind as the next revolution in Cancer treatment. But there is still a lot to do…That’s basically what came out from my discussion with André Choulika, the CEO of the French CAR-T miracle Cellectis.

Cellectis is probably the most successful Biotech in France. It was founded in 1999 by Choulika himself (not alone though), following the discovery of meganucleases ability to change gene editing. Today, Cellectis is a well-known Biotech company counting over 100 employees end of October and having a market cap north of 1 Billion euros.

The company is now focused on the development of allogenic CAR-T (from generic donors  – i.e. not from the patient themself). With these universal CAR-T candidates (UCARTs). Cellectis has signed a massive partnership with the French pharma Servier, as well as Pfizer (which owns 8% of Cellectis), and has just announced two big milestones for the company within the last few weeks.

It is now able to produce it’s allogenic CAR-T in a GMP settings and it releases results from the “miracle” treatment of a 11-month old girl from the UK with multi-resistant leukemia.


Let’s start directly with the latest news…People seemed over-enthusiastic about UCART19…even the New York Times wrote about it. What do you think?

It’s a great news for Cellectis even though it’s still a very early result, in a single patient only. What’s important for us is that the first human patient received our treatment without showing any adverse effects (such as no cytokinetic storm) and our CAR-T cells were still active in the body 3 months after the injections.

Now, we have to expand the clinical trials to several patients and showing data from a cohort of patients. We are now on track to file the clinical trial application by the end of the year.

Your approach in the CAR-T is pretty unique. You are using donor’s cells to treat many different patients, whereas most CAR-T approaches are autologous (i.e. engineered the patient’s own cells).  Is the future in CAR-T the allogenic approach alone?

When we started to move into the CAR-T field we were pretty reluctant because there are not many examples of commercial success in the field yet. But CAR-T has still attracted many big players such as Novartis, Celgene, Juno or Kite. These each have a strong involvement in making autologous therapies work commercially (Celgene especially, which makes most of its revenue from groundbreaking and pricey cancer drugs).

On our side, we want to make this therapy accessible to a larger population and have good market access at the end. We have already pretty good reason to think it could work out well for us. We’ll see though…

Comment: Reuters published a report a few weeks ago estimating the cost of autologous CAR-T could be above $450K per treatment, which would make it economically not realistic for the healthcare payers.

CAR-T seems to be extremely hype right now. At BIO-Europe 2015, I had the impression everybody was talking about CAR-T. Do you think it could have the same impact as monoclonal antibodies?

What’s interesting with CAR-T is that you can target cells which expresses less receptors (10k receptors instead of 100k for monoclonal antibodies). This increases the targets for CAR-T and the possibilities linked.

But there are also downsides. Tissues with low expressions can become targets too and CAR-T cells would start attacking healthy cells.

People should not overemphasise CAR-T. We are still at the beginning of the beginning of this technology. And it will probably have to be combined with surgery or checkpoint inhibitors.


You seem pessimistic about CAR-T…?

I am just trying to be more realistic, even though I am super positive about the technology. It will bring something really great to Haematology field, but is not a cure for Cancer. It’s more of a long-haul race in the right direction as opposed to fast results, and we expect great things perhaps 20 years down the line as opposed to 2016.

But yes, it will probably not be the miracle product some people are talking about.

As for every early technology, there are many challenges associated with its development. What are the main ones worth discussing?

I would say you have four main challenges…

The administration of the cells will be challenging. We have to find way of injecting repeated doses of the product (to ensure the therapy is fully effective seeing as CAR-T cells have a limited lifespan). This is difficult because of immunogenicty against the therapy.

Secondly, combination will play an essential role too and checkpoint inhibitors should be involved.

The last two are linked to the targets.

As I mentioned before, CAR-T can be too sensitive and one way to control that would be to induce “logic gates” where the cells would only act if a combination of receptors would be present. The last challenge is to find other antigens.

Most of the CAR-T cells today target the same antigen: CD19+. We should find new antigens and many companies are on the track, including us.



An anti-CD19 CAR-expressing T cell recognizing a CD19+ (Source: Kochenderfer et al., Nature Reviews Clinical Oncology 10, 267-276, doi: 10.1038/nrclinonc.2013.46)

Autologous CART therapy

Dr. Carl June of University of Pennsylvania, who has helped pioneer the field of CAR-T therapy for leukemia, has also been cautiously hopeful on the progress of the therapy. In his 2015 AACR National Meeting address, he highlighted some achievements they had with CAR-T therapy in both hematologic as well as solid tumors however it was stressed that there is much work to do with regards to optimization of the system, characterization of new tumor antigens for diverse tumor types, as well as the need to develop optimal treatment strategies to mitigate toxicities. Indeed many of the pioneers in the field have been proactive in helping to develop pharmacovigilance, safety, and regulatory strategies (highlighted in a post found here: NIH Considers Guidelines for CAR-T therapy: Report from Recombinant DNA Advisory Committee and mitigating toxicities in a post Steroids, Inflammation, and CAR-T Therapy) and much credit should be given to these researchers.


Cancer Research Institute’s Breakthroughs in Cancer Immunotherapy Webinar Series are offered free to the public and feature informative updates from leaders in cancer immunotherapy, followed by a moderated Q&A. On June 10, 2013, Carl H. June, M.D., a specialist in T cell biology and lymphocyte activation at the Perelman School of Medicine, University of Pennsylvania, discussed his groundbreaking work that has led to remarkable remissions of advanced cancer. He focused on recent and ongoing successes in developing treatments with T cells that have been genetically engineered to target cancer. Called chimeric antigen receptor T cells (CAR T cells), these modified immune cells have proven effective at eliminating cancer in some patients, and offer great hope for this emerging strategy in cancer immunotherapy. For more information on this webinar, or to register for upcoming webinars, please visit www.cancerresearch.org/webinars.

Below are reports from the 2015 American Society of Hematology Conference by Novartis on results from CTL109 CART therapy trials. One trial is on response rate in B-cell lymphomas and follicular cell lymphomas while the second report is ongoing trial results in childhood refractory ALL, both conducted at University of Pennsylvania.

Novartis presents response rate data for CART therapy CTL019 in lymphoma

(Ref: Global Post, NASDAQ, PR Newswire)

posted on FirstWorldPharma.com December 6th, 2015

By: Matthew Dennis

Novartis announced Sunday data from an ongoing Phase IIa study demonstrating that the experimental chimaeric antigen receptor T-cell (CART) therapy CTL019 led to an overall response rate (ORR) at three months of 47 percent in adults with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) and an ORR of 73 percent in adults with follicular lymphoma. The results of the trial were presented at the American Society of Hematology annual meeting.

Findings from the study, which was conducted by the University of Pennsylvania’s Perelman School of Medicine, include 15 adults with DLBCL and 11 with follicular lymphoma who were evaluable for response. Results showed that three patients with DLBCL who achieved a partial response (PR) to treatment at three months converted to complete response (CR) by six months. In addition, three patients with follicular lymphoma who achieved a PR at three months converted to CR by six months.

Novartis added that one DLBCL patient with a PR at three months experienced disease progression at six months after treatment. Further, one follicular lymphoma patient with a PR at three months who remained in PR at nine months experienced disease progression at approximately 12 months after treatment. The company indicated that median progression-free survival was 11.9 months for patients with follicular lymphoma and 3 months for those with DLBCL.

In the study, four patients developed cytokine release syndrome (CRS) of grade 3 or higher. Novartis noted that during CRS, patients typically experience varying degrees of influenza-like symptoms with high fevers, nausea, muscle pain, and in some cases, low blood pressure and breathing difficulties. Meanwhile, neurologic toxicity occurred in two patients in the trial, including one grade three episode of delirium and one possibly related grade five encephalopathy.

“These data add to the growing body of clinical evidence on CTL019 and illustrate its potential benefit in the treatment of relapsed and refractory non-Hodgkin lymphoma,” commented lead investigator Stephen Schuster. Novartis indicated that the findings keep CTL019 on track for submission to the FDA in 2017. Usman Azam, global head of Novartis’ cell and gene therapies unit, said “we remain consistent again with the data set.”

“It’s an attractive population, it’s a population that continues to have a huge unmet need, it’s a cornerstone of our investments,” Azam remarked. Analysts expect CART therapies, once approved, to cost up to $450 000 per patient. Novartis acknowledged that prices will be high, but declined to give further details. “With any disruptive innovation that comes, initially, cost of goods is very challenging,” Azam said, adding “as time goes on, and more patients are treated, we will simplify that cost base.”

Source: http://www.firstwordpharma.com/node/1338217?tsid=28&region_id=2#axzz3tfDVaT1f



Novartis AG (NVS)’s Experimental Therapy Wipes Out Blood Cancer in 93 Percent of Patients

Reported in Biospace.com (for full article see here)

Novaritis and University of Pennsylvania reported results of the CTL019 CART trials for the treatment of children with relapsed/refractory acute lymphoblastic leukemia at the 2015 Annual Hemotologic Society Meeting. 55 of 59 patients, or 93 percent, experienced complete remissions with CTL019. The study did show that at the end of one year, 55 percent of patients had a remission-free survival rate and that 18 patients continued to show complete remission following one year


Other posts on the Open Access Journal on CAR-T therapy include


CAR-T therapy in leukemia

Steroids, Inflammation, and CAR-T Therapy

NIH Considers Guidelines for CAR-T therapy: Report from Recombinant DNA Advisory Committee


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New FDA Draft Guidance On Homologous Use of Human Cells, Tissues, and Cellular and Tissue-Based Products – Implications for 3D BioPrinting of Regenerative Tissue

Reporter: Stephen J. Williams, Ph.D.

The FDA recently came out with a Draft Guidance on use of human cells, tissues and cellular and tissue-based products (HCT/P) {defined in 21 CFR 1271.3(d)} and their use in medical procedures. Although the draft guidance was to expand on previous guidelines to prevent the introduction, transmission, and spread of communicable diseases, this updated draft may have implications for use of such tissue in the emerging medical 3D printing field.

A full copy of the PDF can be found here for reference but the following is a summary of points of the guidance.FO508ver – 2015-373 HomologousUseGuidanceFinal102715

In 21 CFR 1271.10, the regulations identify the criteria for regulation solely under section 361 of the PHS Act and 21 CFR Part 1271. An HCT/P is regulated solely under section 361 of the PHS Act and 21 CFR Part 1271 if it meets all of the following criteria (21 CFR 1271.10(a)):

  • The HCT/P is minimally manipulated;
  • The HCT/P is intended for homologous use only, as reflected by the labeling, advertising, or other indications of the manufacturer’s objective intent;
  • The manufacture of the HCT/P does not involve the combination of the cells or tissues with another article, except for water, crystalloids, or a sterilizing, preserving, or storage agent, provided that the addition of water, crystalloids, or the sterilizing, preserving, or storage agent does not raise new clinical safety concerns with respect to the HCT/P; and
  • Either:
  1. The HCT/P does not have a systemic effect and is not dependent upon the metabolic activity of living cells for its primary function; or
  2. The HCT/P has a systemic effect or is dependent upon the metabolic activity of living cells for its primary function, and:
  3. Is for autologous use;
  4. Is for allogeneic use in a first-degree or second-degree blood relative; or
  5. Is for reproductive use.

If an HCT/P does not meet all of the criteria in 21 CFR 1271.10(a), and the establishment that manufactures the HCT/P does not qualify for any of the exceptions in 21 CFR 1271.15, the HCT/P will be regulated as a drug, device, and/or biological product under the Federal Food, Drug and Cosmetic Act (FD&C Act), and/or section 351 of the PHS Act, and applicable regulations, including 21 CFR Part 1271, and pre-market review will be required.

1 Examples of HCT/Ps include, but are not limited to, bone, ligament, skin, dura mater, heart valve, cornea, hematopoietic stem/progenitor cells derived from peripheral and cord blood, manipulated autologous chondrocytes, epithelial cells on a synthetic matrix, and semen or other reproductive tissue. The following articles are not considered HCT/Ps: (1) Vascularized human organs for transplantation; (2) Whole blood or blood components or blood derivative products subject to listing under 21 CFR Parts 607 and 207, respectively; (3) Secreted or extracted human products, such as milk, collagen, and cell factors, except that semen is considered an HCT/P; (4) Minimally manipulated bone marrow for homologous use and not combined with another article (except for water, crystalloids, or a sterilizing, preserving, or storage agent, if the addition of the agent does not raise new clinical safety concerns with respect to the bone marrow); (5) Ancillary products used in the manufacture of HCT/P; (6) Cells, tissues, and organs derived from animals other than humans; (7) In vitro diagnostic products as defined in 21 CFR 809.3(a); and (8) Blood vessels recovered with an organ, as defined in 42 CFR 121.2 that are intended for use in organ transplantation and labeled “For use in organ transplantation only.” (21 CFR 1271.3(d))

Contains Nonbinding Recommendations
Draft – Not for Implementation

Section 1271.10(a)(2) (21 CFR 1271.10(a)(2)) provides that one of the criteria for an HCT/P to be regulated solely under section 361 of the PHS Act is that the “HCT/P is intended for homologous use only, as reflected by the labeling, advertising, or other indications of the manufacturer’s objective intent.” As defined in 21 CFR 1271.3(c), homologous use means the repair, reconstruction, replacement, or supplementation of a recipient’s cells or tissues with an HCT/P that performs the same basic function or functions in the recipient as in the donor. This criterion reflects the Agency’s conclusion that there would be increased safety and effectiveness concerns for HCT/Ps that are intended for a non-homologous use, because there is less basis on which to predict the product’s behavior, whereas HCT/Ps for homologous use can reasonably be expected to function appropriately (assuming all of the other criteria are also met).2 In applying the homologous use criterion, FDA will determine what the intended use of the HCT/P is, as reflected by the the labeling, advertising, and other indications of a manufacturer’s objective intent, and will then apply the homologous use definition.

FDA has received many inquiries from manufacturers about whether their HCT/Ps meet the homologous use criterion in 21 CFR 1271.10(a)(2). Additionally, transplant and healthcare providers often need to know this information about the HCT/Ps that they are considering for use in their patients. This guidance provides examples of different types of HCT/Ps and how the regulation in 21 CFR 1271.10(a)(2) applies to them, and provides general principles that can be applied to HCT/Ps that may be developed in the future. In some of the examples, the HCT/Ps may fail to meet more than one of the four criteria in 21 CFR 1271.10(a).


  1. What is the definition of homologous use?

Homologous use means the repair, reconstruction, replacement, or supplementation of a recipient’s cells or tissues with an HCT/P that performs the same basic function or functions in the recipient as in the donor (21 CFR 1271.3(c)), including when such cells or tissues are for autologous use. We generally consider an HCT/P to be for homologous use when it is used to repair, reconstruct, replace, or supplement:

  • Recipient cells or tissues that are identical (e.g., skin for skin) to the donor cells or tissues, and perform one or more of the same basic functions in the recipient as the cells or tissues performed in the donor; or,
  • Recipient cells that may not be identical to the donor’s cells, or recipient tissues that may not be identical to the donor’s tissues, but that perform one or more of the same basic functions in the recipient as the cells or tissues performed in the donor.3

2 Proposed Approach to Regulation of Cellular and Tissue-Based Products, FDA Docket. No. 97N-0068 (February. 28, 1997) page 19. http://www.fda.gov/downloads/biologicsbloodvaccines/guidancecomplianceregulatoryinformation/guidances/tissue/ ucm062601.pdf.

3“Establishment Registration and Listing for Manufacturers of Human Cellular and Tissue-Based Products” 63 FR 26744 at 26749 (May 14, 1998).

Contains Nonbinding Recommendations
Draft – Not for Implementation

1-1. A heart valve is transplanted to replace a dysfunctional heart valve. This is homologous use because the donor heart valve performs the same basic function in the donor as in the recipient of ensuring unidirectional blood flow within the heart.

1-2. Pericardium is intended to be used as a wound covering for dura mater defects. This is homologous use because the pericardium is intended to repair or reconstruct the dura mater and serve as a covering in the recipient, which is one of the basic functions it performs in the donor.

Generally, if an HCT/P is intended for use as an unproven treatment for a myriad of

diseases or conditions, the HCT/P is likely not intended for homologous use only.4

  1. What does FDA mean by repair, reconstruction, replacement, or supplementation of a recipient’s cells or tissues?

Repair generally means the physical or mechanical restoration of tissues, including by covering or protecting. For example, FDA generally would consider skin removed from a donor and then transplanted to a recipient in order to cover a burn wound to be a homologous use. Reconstruction generally means surgical reassembling or re-forming. For example, reconstruction generally would include the reestablishment of the physical integrity of a damaged aorta.5 Replacement generally means substitution of a missing tissue or cell, for example, the replacement of a damaged or diseased cornea with a healthy cornea or the replacement of donor hematopoietic stem/progenitor cells in a recipient with a disorder affecting the hematopoietic system that is inherited, acquired, or the result of myeloablative treatment. Supplementation generally means to add to, or complete. For example, FDA generally would consider homologous uses to be the implantation of dermal matrix into the facial wrinkles to supplement a recipient’s tissues and the use of bone chips to supplement bony defects. Repair, reconstruction, replacement, and supplementation are not mutually exclusive functions and an HCT/P could perform more than one of these functions for a given intended use.

  1. What does FDA mean by “the same basic function or functions” in the definition of homologous use?

For the purpose of applying the regulatory framework, the same basic function or functions of HCT/Ps are considered to be those basic functions the HCT/P performs in the body of the donor, which, when transplanted, implanted, infused, or transferred, the HCT/P would be expected to perform in the recipient. It is not necessary for the HCT/P in the recipient to perform all of the basic functions it performed in the donor, in order to

4 “Human Cells, Tissues, and Cellular and Tissue-Based Products; Establishment Registration and Listing” 66 FR 5447 at 5458 (January 19, 2001).

5 “Current Good Tissue Practice for Human Cell, Tissue, and Cellular and Tissue-Based Product Establishments; Inspection and Enforcement” 69 FR 68612 at 68643 (November 24, 2004) states, “HCT/Ps with claims for “reconstruction or repair” can be regulated solely under section 361 of the PHS Act, provided the HCT/P meets all the criteria in § 1271.10, including minimal manipulation and homologous use.”

Contains Nonbinding Recommendations
Draft – Not for Implementation

meet the definition of homologous use. However, to meet the definition of homologous use, any of the basic functions that the HCT/P is expected to perform in the recipient must be a basic function that the HCT/P performed in the donor.

A homologous use for a structural tissue would generally be to perform a structural function in the recipient, for example, to physically support or serve as a barrier or conduit, or connect, cover, or cushion.

A homologous use for a cellular or nonstructural tissue would generally be a metabolic or biochemical function in the recipient, such as, hematopoietic, immune, and endocrine functions.

3-1. The basic functions of hematopoietic stem/progenitor cells (HPCs) include to form and to replenish the hematopoietic system. Sources of HPCs include cord blood, peripheral blood, and bone marrow.6

  1. HPCs derived from peripheral blood are intended for transplantation into an individual with a disorder affecting the hematopoietic system that is inherited, acquired, or the result of myeloablative treatment. This is homologous use because the peripheral blood product performs the same basic function of reconstituting the hematopoietic system in the recipient.
  2. HPCs derived from bone marrow are infused into an artery with a balloon catheter for the purpose of limiting ventricular remodeling following acute myocardial infarction. This is not homologous use because limiting ventricular remodeling is not a basic function of bone marrow.
  3. A manufacturer provides HPCs derived from cord blood with a package insert stating that cord blood may be infused intravenously to differentiate into neuronal cells for treatment of cerebral palsy. This is not homologous use because there is insufficient evidence to support that such differentiation is a basic function of these cells in the donor.

3-2. The basic functions of the cornea include protecting the eye by forming its outermost layer and serving as the refracting medium of the eye. A corneal graft is transplanted to restore sight in a patient with corneal blindness. This is homologous use because a corneal graft performs the same basic functions in the donor as in the recipient.

3-3. The basic functions of a vein or artery include serving as a conduit for blood flow throughout the body. A cryopreserved vein or artery is used for arteriovenous access during hemodialysis. This is homologous use because the vein or artery is supplementing the vessel as a conduit for blood flow.

3-4. The basic functions of amniotic membrane include covering, protecting, serving as a selective barrier for the movement of nutrients between the external and in utero

6 Bone marrow meets the definition of an HCT/P only if is it more than minimally manipulated; intended by the manufacturer for a non-homologous use, or combined with certain drugs or devices.

Contains Nonbinding Recommendations
Draft – Not for Implementation

environment, and to retain fluid in utero. Amniotic membrane is used for bone tissue replacement to support bone regeneration following surgery to repair or replace bone defects. This is not a homologous use because bone regeneration is not a basic function of amniotic membrane.

3-5. The basic functions of pericardium include covering, protecting against infection, fixing the heart to the mediastinum, and providing lubrication to allow normal heart movement within chest. Autologous pericardium is used to replace a dysfunctional heart valve in the same patient. This is not homologous use because facilitating unidirectional blood flow is not a basic function of pericardium.

  1. Does my HCT/P have to be used in the same anatomic location to perform the same basic function or functions?

An HCT/P may perform the same basic function or functions even when it is not used in the same anatomic location where it existed in the donor.7 A transplanted HCT/P could replace missing tissue, or repair, reconstruct, or supplement tissue that is missing or damaged, either when placed in the same or different anatomic location, as long as it performs the same basic function(s) in the recipient as in the donor.

4-1. The basic functions of skin include covering, protecting the body from external force, and serving as a water-resistant barrier to pathogens or other damaging agents in the external environment. The dermis is the elastic connective tissue layer of the skin that provides a supportive layer of the integument and protects the body from mechanical stress.

  1. An acellular dermal product is used for supplemental support, protection, reinforcement, or covering for a tendon. This is homologous use because in both anatomic locations, the dermis provides support and protects the soft tissue structure from mechanical stress.
  2. An acellular dermal product is used for tendon replacement or repair. This is not homologous use because serving as a connection between muscle and bone is not a basic function of dermis.

4-2. The basic functions of amniotic membrane include serving as a selective barrier for the movement of nutrients between the external and in utero environment and to retain fluid in utero. An amniotic membrane product is used for wound healing of dermal ulcers and defects. This is not homologous use because wound healing of dermal lesions is not a basic function of amniotic membrane.

4-3. The basic functions of pancreatic islets include regulating glucose homeostasis within the body. Pancreatic islets are transplanted into the liver through the portal vein,

7 “Human Cells, Tissues, and Cellular and Tissue-Based Products; Establishment Registration and Listing” 66 FR 5447 at 5458 (January 19, 2001).


Contains Nonbinding Recommendations
Draft – Not for Implementation

for preservation of endocrine function after pancreatectomy. This is homologous use because the regulation of glucose homeostasis is a basic function of pancreatic islets.

  1. What does FDA mean by “intended for homologous use” in 21 CFR 1271.10(a)(2)?

The regulatory criterion in 21 CFR 1271.10(a)(2) states that the HCT/P is intended for homologous use only, as reflected by the labeling, advertising, or other indications of the manufacturer’s objective intent.

Labeling includes the HCT/P label and any written, printed, or graphic materials that supplement, explain, or are textually related to the product, and which are disseminated by or on behalf of its manufacturer.8 Advertising includes information, other than labeling, that originates from the same source as the product and that is intended to supplement, explain, or be textually related to the product (e.g., print advertising, broadcast advertising, electronic advertising (including the Internet), statements of company representatives).9

An HCT/P is intended for homologous use when its labeling, advertising, or other indications of the manufacturer’s objective intent refer to only homologous uses for the HCT/P. When an HCT/P’s labeling, advertising, or other indications of the manufacturer’s objective intent refer to non-homologous uses, the HCT/P would not meet the homologous use criterion in 21 CFR 1271.10(a)(2).

  1. What does FDA mean by “manufacturer’s objective intent” in 21 CFR 1271.10(a)(2)?

A manufacturer’s objective intent is determined by the expressions of the manufacturer or its representatives, or may be shown by the circumstances surrounding the distribution of the article. A manufacturer’s objective intent may, for example, be shown by labeling claims, advertising matter, or oral or written statements by the manufacturer or its representatives. It may be shown by the circumstances that the HCT/P is, with the knowledge of the manufacturer or its representatives, offered for a purpose for which it is neither labeled nor advertised.

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NIH Considers Guidelines for CAR-T therapy: Report from Recombinant DNA Advisory Committee

Reporter: Stephen J. Williams, Ph.D.

UPDATED 5/10/2022

In the mid to late 1970’s a public debate (and related hysteria) had emerged surrounding two emerging advances in recombinant DNA technology;

  1. the development of vectors useful for cloning pieces of DNA (the first vector named pBR322) and
  2. the discovery of bacterial strains useful in propagating such vectors

As discussed by D. S, Fredrickson of NIH’s Dept. of Education and Welfare in his historical review” A HISTORY OF THE RECOMBINANT DNA GUIDELINES IN THE UNITED STATES” this international concern of the biological safety issues of this new molecular biology tool led the National Institute of Health to coordinate a committee (the NIH Recombinant DNA Advisory Committee) to develop guidelines for the ethical use, safe development, and safe handling of such vectors and host bacterium. The first conversations started in 1974 and, by 1978, initial guidelines had been developed. In fact, as Dr. Fredrickson notes, public relief was voiced even by religious organizations (who had the greatest ethical concerns)

On December 16, 1978, a telegram purporting to be from the Vatican was hand delivered to the office of Joseph A. Califano, Jr., Secretary of Health, Education,

and Welfare. “Habemus regimen recombinatum,” it proclaimed, in celebration of the

end of a long struggle to revise the NIH Guidelines for Research Involving

Recombinant DNA Molecules

The overall Committee resulted in guidelines (2013 version) which assured the worldwide community that

  • organisms used in such procedures would have limited pathogenicity in humans
  • vectors would be developed in a manner which would eliminate their ability to replicate in humans and have defined antibiotic sensitivity

So great was the success and acceptance of this committee and guidelines, the NIH felt the Recombinant DNA Advisory Committee should meet regularly to discuss and develop ethical guidelines and clinical regulations concerning DNA-based therapeutics and technologies.

A PowerPoint Slideshow: Introduction to NIH OBA and the History of Recombinant DNA Oversight can be viewed at the following link:


Please see the following link for a video discussion between Dr. Paul Berg, who pioneered DNA recombinant technology, and Dr. James Watson (Commemorating 50 Years of DNA Science):


The Recombinant DNA Advisory Committee has met numerous times to discuss new DNA-based technologies and their biosafety and clinical implication including:

A recent Symposium was held in the summer of 2010 to discuss ethical and safety concerns and discuss potential clinical guidelines for use of an emerging immunotherapy technology, the Chimeric Antigen Receptor T-Cells (CART), which at that time had just been started to be used in clinical trials.

Considerations for the Clinical Application of Chimeric Antigen Receptor T Cells: Observations from a Recombinant DNA Advisory Committee Symposium Held June 15, 2010[1]

Contributors to the Symposium discussing opinions regarding CAR-T protocol design included some of the prominent members in the field including:

Drs. Hildegund C.J. Ertl, John Zaia, Steven A. Rosenberg, Carl H. June, Gianpietro Dotti, Jeffrey Kahn, Laurence J. N. Cooper, Jacqueline Corrigan-Curay, And Scott E. Strome.

The discussions from the Symposium, reported in Cancer Research[1]. were presented in three parts:

  1. Summary of the Evolution of the CAR therapy
  2. Points for Future Consideration including adverse event reporting
  3. Considerations for Design and Implementation of Trials including mitigating toxicities and risks

1. Evolution of Chimeric Antigen Receptors

Early evidence had suggested that adoptive transfer of tumor-infiltrating lymphocytes, after depletion of circulating lymphocytes, could result in a clinical response in some tumor patients however developments showed autologous T-cells (obtained from same patient) could be engineered to express tumor-associated antigens (TAA) and replace the TILS in the clinical setting.

However there were some problems noticed.

  • Problem: HLA restriction of T-cells. Solution: genetically engineer T-cells to redirect T-cell specificity to surface TAAs
  • Problem: 1st generation vectors designed to engineer T-cells to recognize surface epitopes but engineered cells had limited survival in patients.   Solution: development of 2nd generation vectors with co-stimulatory molecules such as CD28, CD19 to improve survival and proliferation in patients

A summary table of limitations of the two types of genetically-modified T-cell therapies were given and given (in modified form) below

                                                                                                Type of Gene-modified T-Cell

Limitations aβ TCR CAR
Affected by loss or decrease of HLA on tumor cells yes no
Affected by altered tumor cell antigen processing? yes no
Need to have defined tumor target antigen? no yes
Vector recombination with endogenous TCR yes no

A brief history of construction of 2nd and 3rd generation CAR-T cells given by cancer.gov:



Differences between  second- and third-generation chimeric antigen receptor T cells. (Adapted by permission from the American Association for Cancer Research: Lee, DW et al. The Future Is Now: Chimeric Antigen Receptors as New Targeted Therapies for Childhood Cancer. Clin Cancer Res; 2012;18(10); 2780–90. doi:10.1158/1078-0432.CCR-11-1920)

Constructing a CAR T Cell (from cancer.gov)

The first efforts to engineer T cells to be used as a cancer treatment began in the early 1990s. Since then, researchers have learned how to produce T cells that express chimeric antigen receptors (CARs) that recognize specific targets on cancer cells.

The T cells are genetically modified to produce these receptors. To do this, researchers use viral vectors that are stripped of their ability to cause illness but that retain the capacity to integrate into cells’ DNA to deliver the genetic material needed to produce the T-cell receptors.

The second- and third-generation CARs typically consist of a piece of monoclonal antibody, called a single-chain variable fragment (scFv), that resides on the outside of the T-cell membrane and is linked to stimulatory molecules (Co-stim 1 and Co-stim 2) inside the T cell. The scFv portion guides the cell to its target antigen. Once the T cell binds to its target antigen, the stimulatory molecules provide the necessary signals for the T cell to become fully active. In this fully active state, the T cells can more effectively proliferate and attack cancer cells.

2. Adverse Event Reporting and Protocol Considerations

The symposium had been organized mainly in response to two reported deaths of patients enrolled in a CART trial, so that clinical investigators could discuss and formulate best practices for the proper conduct and analysis of such trials. One issue raised was lack of pharmacovigilence procedures (adverse event reporting). Although no pharmacovigilence procedures (either intra or inter-institutional) were devised from meeting proceedings, it was stressed that each institution should address this issue as well as better clinical outcome reporting.

Case Report of a Serious Adverse Event Following the Administration of T Cells Transduced With a Chimeric Antigen Receptor Recognizing ERBB2[2] had reported the death of a patient on trial.

In A phase I clinical trial of adoptive transfer of folate receptor-alpha redirected autologous T cells for recurrent ovarian cancer[3] authors: Lana E Kandalaft*, Daniel J Powell and George Coukos from University of Pennsylvania recorded adverse events in pilot studies using a CART modified to recognize the folate receptor, so it appears any adverse event reporting system is at the discretion of the primary investigator.

Other protocol considerations suggested by the symposium attendants included:

  • Plan for translational clinical lab for routine blood analysis
  • Subject screening for pulmonary and cardiac events
  • Determine possibility of insertional mutagenesis
  • Informed consent
  • Analysis of non T and T-cell subsets, e.g. natural killer cells and CD*8 cells

3. Consideration for Design of Trials and Mitigating Toxicities

  • Early Toxic effectsCytokine Release Syndrome– The effectiveness of CART therapy has been manifested by release of high levels of cytokines resulting in fever and inflammatory sequelae. One such cytokine, interleukin 6, has been attributed to this side effect and investigators have successfully used an IL6 receptor antagonist, tocilizumab (Acterma™), to alleviate symptoms of cytokine release syndrome (see review Adoptive T-cell therapy: adverse events and safety switches by Siok-Keen Tey).


Below is a video form Dr. Renier Brentjens, M.D., Ph.D. for Memorial Sloan Kettering concerning the finding he made that the adverse event from cytokine release syndrome may be a function of the tumor cell load, and if they treat the patient with CAR-T right after salvage chemotherapy the adverse events are alleviated..

Please see video below:

http link: https://www.youtube.com/watch?v=4Gg6elUMIVE

  • Early Toxic effects – Over-activation of CAR T-cells; mitigation by dose escalation strategy (as authors in reference [3] proposed). Most trials give billions of genetically modified cells to a patient.
  • Late Toxic Effectslong-term depletion of B-cells . For example CART directing against CD19 or CD20 on B cells may deplete the normal population of CD19 or CD20 B-cells over time; possibly managed by IgG supplementation

Below is a curation of various examples of the need for developing a Pharmacovigilence Framework for Engineered T-Cell Therapies

As shown above the first reported side effects from engineered T-cell or CAR-T therapies stemmed from the first human trial occuring at University of Pennsylvania, the developers of the first CAR-T therapy.  The clinical investigators however anticipated the issue of a potential cytokine storm and had developed ideas in the pre-trial phase of how to ameliorate such toxicity using anti-cytokine antibodies.  However, until the trial was underway they were unsure of which cytokines would be prominent in causing a cytokine storm effect from the CAR-T therapy.  Fortunately, the investigators were able to save patient 1 (described here in other posts) using anti-IL1 and 10 antibodies.  


Over the years, however, multiple trials had to be discontinued as shown below in the following posts:

What does this mean for Immunotherapy? FDA put a temporary hold on Juno’s JCAR015, Three Death of Celebral Edema in CAR-T Clinical Trial and Kite Pharma announced Phase II portion of its CAR-T ZUMA-1 trial

The NIH has put a crimp in the clinical trial work of Steven Rosenberg, Kite Pharma’s star collaborator at the National Cancer Institute. The feds slammed the brakes on the production of experimental drugs at two of its facilities–including cell therapies that Rosenberg works with–after an internal inspection found they weren’t in compliance with safety and quality regulations.

In this instance Kite was being cited for manufacturing issues, apparantly fungal contamination in their cell therapy manufacturing facility.  However shortly after other CAR-T developers were having tragic deaths in their initial phase 1 safety studies.

Juno Halts Cancer Trial Using Gene-Altered Cells After 3 Deaths


Juno halts its immunotherapy trial for cancer after three patient deaths

By DAMIAN GARDE @damiangarde and MEGHANA KESHAVAN @megkesh

JULY 7, 2016

In Juno patient deaths, echoes seen of earlier failed company


JULY 8, 2016


After a deadly clinical trial, will immune therapies for cancer be a bust?

By DAMIAN GARDE @damiangarde

JULY 8, 2016

This led to warnings by FDA and alteration of their trials as well as the use of their CART as a monotherapy

Hours after Juno CAR-T study deaths announced, Kite enrolls CAR-T PhII

Well That Was Quick! FDA Lets Juno Restart Trial With a New Combination Chemotherapuetic

 at Seattle Times

FDA lets Juno restart cancer-treatment trial

Certainly with so many issues there would seem to be more rigorous work to either establish a pharmacovigilence framework or to develop alternative engineered T cells with a safer profile

However here we went again

New paper sheds fresh light on Tmunity’s high-profile CAR-T deaths
Jason Mast
The industry-wide effort to push CAR-T therapies — wildly effective in several blood cancers — into solid tumors took a hit last year when Tmunity, a biotech founded by CAR-T pioneer Carl June and backed by several blue-chip VCs, announced it shut down its lead program for prostate cancer after two patients died.

On a personal note this trial was announced in a Bio International meeting here in Philadelphia a few years ago in 2019

see Live Conference Coverage on this site

eProceedings for BIO 2019 International Convention, June 3-6, 2019 Philadelphia Convention Center; Philadelphia PA, Real Time Coverage by Stephen J. Williams, PhD @StephenJWillia2

and the indication was for prostate cancer, in particular hormone resistant castration resistant.  Another one was planned for pancreatic cancer from the same group and the early indications were favorable.

From Onclive

Source: https://www.onclive.com/view/car-t-cell-therapy-trial-in-solid-tumors-halted-following-2-patient-deaths 

Tmunity Therapeutics, a clinical-stage biotherapeutics company, has halted the development of its lead CAR T-cell product following the deaths of 2 patients who were enrolled to a trial investigating its use in solid tumors.1

The patients reportedly died from immune effector cell-associated neurotoxicity syndrome (ICANS), which is a known adverse effect associated with CAR T-cell therapies.

“What we are discovering is that the cytokine profiles we see in solid tumors are completely different from hematologic cancers,” Oz Azam, co-founder of Tmunity said in an interview with Endpoints News. “We observed ICANS. And we had 2 patient deaths as a result of that. We navigated the first event and obviously saw the second event, and as a result of that we have shut down the version one of that program and pivoted quickly to our second generation.”

Previously, with first-generation CAR T-cell therapies in patients with blood cancers, investigators were presented with the challenge of overcoming cytokine release syndrome. Now ICANS, or macrophage activation, is proving to have deadly effects in the realm of solid tumors. Carl June, the other co-founder of Tmunity, noted that investigators will now need to dedicate their efforts to engineering around this, as had been done with tocilizumab (Actemra) in 2012.

The company is dedicated to the development of novel approaches that produce best-in-class control over T-cell activation and direction in the body.2 The product examined in the trial was developed to utilize engineered patient cells to target prostate-specific membrane antigen; it was also designed to use a dominant TGFβ receptor to block an important checkpoint involved in cancer.

Twenty-four patients were recruited for the dose-escalating study and the company plans to release data from high-dose cohorts later in 2021.

“We are going to present all of this in a peer-reviewed publication because we want to share this with the field,” Azam said. “Because everything we’ve encountered, no matter what…people are going to encounter this when they get into the clinic, and I don’t think they’ve really understood yet because so many are preclinical companies that are not in the clinic with solid tumors. And the rubber meets the road when you get in the clinic, because the ultimate in vivo model is the human model.”

Azam added that the company plans to develop a new investigational new drug for version 2, which they hope will result in a safer product.


  1. Carroll J. Exclusive: Carl June’s Tmunity encounters a lethal roadblock as 2 patient deaths derail lead trial, raise red flag forcing rethink of CAR-T for solid tumors. Endpoints News. June 2, 2021. Accessed June 3, 2021. https://bit.ly/3wPYWm0
  2. Research and Development. Tmunity Therapeutics website. Accessed June 3, 2021. https://bit.ly/3fOH3OR

Forward to 2022

Reprogramming a new type of T cell to go after cancers with less side effects, longer impact

A Sloan Kettering Institute research team thinks new, killer, innate-like T cells could make promising candidates to treat cancers that so far haven’t responded to immunotherapy treatments. (koto_feja)

Immunotherapy is one of the more appealing and effective kinds of cancer treatment when it works, but the relatively new approach is still fairly limited in the kinds of cancer it can be used for. Researchers at the Sloan Kettering Institute have discovered a new kind of immune cell and how it could be used to expand the reach of immunotherapy treatments to a much wider pool of patients.

The cells in question are called killer innate-like T cells, a threatening name for a potentially lifesaving innovation. Unlike normal killer T cells, killer innate-like T cells stay active much longer and can burrow further into potentially cancerous tissue to attack tumors. The research team first reported these cells in 2016, but it’s only recently that they were able to properly understand and identify them.

“We think these killer innate-like T cells could be targeted or genetically engineered for cancer therapy,” said the study’s lead author, Ming Li, Ph.D., in a press release. “They may be better at reaching and killing solid tumors than conventional T cells.”

Below is the referenced paper from Pubmed:

Evaluation of the safety and efficacy of humanized anti-CD19 chimeric antigen receptor T-cell therapy in older patients with relapsed/refractory diffuse large B-cell lymphoma based on the comprehensive geriatric assessment system



Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has led to unprecedented results to date in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), yet its clinical application in elderly patients with R/R DLBCL remains somewhat limited. In this study, a total of 31 R/R DLBCL patients older than 65 years of age were enrolled and received humanized anti-CD19 CAR T-cell therapy. Patients were stratified into a fit, unfit, or frail group according to the comprehensive geriatric assessment (CGA). The fit group had a higher objective response (OR) rate (ORR) and complete response (CR) rate than that of the unfit/frail group, but there was no difference in the part response (PR) rate between the groups. The unfit/frail group was more likely to experience AEs than the fit group. The peak proportion of anti-CD19 CAR T-cells in the fit group was significantly higher than that of the unfit/frail group. The CGA can be used to effectively predict the treatment response, adverse events, and long-term survival.


Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL), accounting for 30–40% of cases, with the median age of onset being older than 65 years [1]. Although the five-year survival rate for patients with DLBCL has risen to more than 60% with the application of standardized treatments and hematopoietic stem cell transplantation, nearly half of patients progress to relapsed/refractory (R/R) DLBCL. Patients with R/R DLBCL, especially elderly individuals, have a poor prognosis [2,3], so new treatments are needed to prolong survival and improve the prognosis of this population.

As a revolutionary immunotherapy therapy, anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has achieved unprecedented results in hematological tumors [4]. As CD19 is expressed on the surface of most B-cell malignant tumors but not on pluripotent bone marrow stem cells, CD19 has been used as a target for B-cell malignancies, including B-cell acute lymphoblastic leukemia, NHL, multiple myeloma, and chronic lymphocytic leukemia [5]. Despite the wide application and high efficacy of anti-CD19 CAR T-cell therapy, reports of adverse events (AEs) such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxic syndrome (ICANS) have influenced its use [6]. Especially in elderly patients, AEs associated with anti-CD19 CAR T-cell therapy might be more obvious.

Although anti-CD19 CAR T-cell therapy has been reported in the treatment of NHL, including R/R DLBCL, few studies to date have assessed the safety of anti-CD19 CAR T-cell therapy in elderly R/R DLBCL patients, and its clinical application in the elderly R/R DLBCL population is limited. In ZUMA-1 [7] to R/R DLBCL patients who received CAR T-cell therapy, the CR rate in patients ≥65 years was higher than that of in patients <65 years (75% vs. 53%). Lin et al. [8] reported 49 R/R DLBCL patients (24 patients >65 years, 25 patients <65 years) who received CAR T-cell therapy with a median follow-up of 179 days. The CR rate at 100 days was 51%, while the 6-month progression-free survival (PFS) and overall survival (OS) were 48% and 71%, respectively. Neither of the two studies carried out a comprehensive geriatric assessment (CGA) of fit, unfit, and frail groups of R/R DLBCL patients over 65 years of age and further analyzed the differences in efficacy and side effects in the three groups. The CGA is an effective system designed to evaluate the prognosis and improve the survival of elderly patients with cancer. The CGA system includes age, activities of daily living (ADL), instrumental ADL (IADL), and the Cumulative Illness Rating Score for Geriatrics (CIRS-G) [9].

In this study, elderly R/R DLBCL patients were grouped according to their CGA results (fit vs. unfit/frail) before receiving humanized anti-CD19 CAR T-cell therapy. We then analyzed the efficacy and AEs of anti-CD19 CAR T-cell therapy and compared findings between these groups.


Well it appears that the discriminator was only fitness going into the trial  a bit odd that the whole field appears to be lacking in development of Safety Biomarkers.



However Genentech (subsidiary of Roche) may now be using some data to develop therapies which may combat resistance to CART therapies which may provide at least, for now, a toxicokinetic approach to reducing AEs by lowering the amount of CARTs needed to be administered.


Source: https://www.fiercebiotech.com/research/genentech-uncovers-how-cancer-cells-resist-t-cell-attack-potential-boon-immunotherapy

Roche’s Genentech is exploring inhibiting ESCRT as an anticancer strategy, said Ira Mellman, Ph.D., Genentech’s vice president of cancer immunology. (Roche)

Cancer cells deploy various tactics to avoid being targeted and killed by the immune system. A research team led by Roche’s Genentech has now identified one such method that cancer cells use to resist T-cell assault by repairing damage.

To destroy their targets, cancer-killing T cells known as cytotoxic T lymphocytes (CTLs) secrete the toxin perforin to form little pores in the target cells’ surface. Another type of toxin called granzymes are delivered directly into the cells through those portals to induce cell death.

By using high-res imaging in live cells, the Genentech-led team found that the membrane damage caused by perforin could trigger a repair response. The tumor cells could recruit endosomal sorting complexes required for transport (ESCRT) proteins to remove the lesions, thereby preventing granzymes from entering, the team showed in a new study published in Science.

The following is the Science paper

Membrane repair in target cell defenses

Killer T cells destroy virus-infected and cancer cells by secreting two protein toxins that act as a powerful one-two punch. Pore-forming toxins, perforins, form holes in the plasma membrane of the target cell. Cytotoxic proteins released by T cells then pass through these portals, inducing target cell death. Ritter et al. combined high-resolution imaging data with functional analysis to demonstrate that tumor-derived cells fight back (see the Perspective by Andrews). Protein complexes of the ESCRT family were able to repair perforin holes in target cells, thereby delaying or preventing T cell–induced killing. ESCRT-mediated membrane repair may thus provide a mechanism of resistance to immune attack. —SMH


Cytotoxic T lymphocytes (CTLs) and natural killer cells kill virus-infected and tumor cells through the polarized release of perforin and granzymes. Perforin is a pore-forming toxin that creates a lesion in the plasma membrane of the target cell through which granzymes enter the cytosol and initiate apoptosis. Endosomal sorting complexes required for transport (ESCRT) proteins are involved in the repair of small membrane wounds. We found that ESCRT proteins were precisely recruited in target cells to sites of CTL engagement immediately after perforin release. Inhibition of ESCRT machinery in cancer-derived cells enhanced their susceptibility to CTL-mediated killing. Thus, repair of perforin pores by ESCRT machinery limits granzyme entry into the cytosol, potentially enabling target cells to resist cytolytic attack.
Cytotoxic lymphocytes, including cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells, are responsible for identifying and destroying virus-infected or tumorigenic cells. To kill their targets, CTLs and NK cells secrete a pore-forming toxin called perforin through which apoptosis-inducing serine proteases (granzymes) are delivered directly into the cytosol. Successful killing of target cells often requires multiple hits from single or multiple T cells (1). This has led to the idea that cytotoxicity is additive, often requiring multiple rounds of sublethal lytic granule secretion events before a sufficient threshold of cytosolic granzyme activity is reached to initiate apoptosis in the target (2).
Loss of plasma membrane integrity induced by cytolytic proteins or mechanical damage leads to a membrane repair response. Damage results in an influx of extracellular Ca2+, which has been proposed to lead to the removal of the membrane lesion by endocytosis, resealing of the lesions by lysosomal secretion, or budding into extracellular vesicles (3). Perforin pore formation was initially reported to enhance endocytosis of perforin (4), but subsequent work has challenged this claim (5). Endosomal sorting complexes required for transport (ESCRT) proteins can repair small wounds and pores in the plasma membrane caused by bacterial pore-forming toxins, mechanical wounding, and laser ablation (67). ESCRT proteins are transiently recruited to sites of membrane damage in a Ca2+-dependent fashion, where they assemble budding structures that shed to eliminate the wound and restore plasma membrane integrity. ESCRT-dependent membrane repair has been implicated in the resealing of endogenous pore-mediated plasma membrane damage during necroptosis (8) and pyroptosis (9).

Localization of target-derived ESCRT proteins to the cytolytic synapse

To investigate whether ESCRT-mediated membrane repair might be involved in the removal of perforin pores during T cell killing, we first determined whether ESCRT proteins in cancer-derived cells were recruited to sites of CTL engagement after perforin secretion. We used CTLs from OT-I mice that express a high-affinity T cell receptor (TCR) that recognizes the ovalbumin peptide SIINFEKL (OVA257-264) bound to the major histocompatibility complex (MHC) allele H-2Kb (10). We performed live-cell microscopy of OT-I CTLs engaging SIINFEKL-pulsed target cells that express enhanced green fluorescent protein (EGFP)–tagged versions of Tsg101 or Chmp4b, two ESCRT proteins implicated in membrane repair (6). To correlate recruitment of ESCRT proteins with perforin exposure in time, we monitored CTL-target interaction in media with a high concentration of propidium iodide (PI), a cell-impermeable fluorogenic dye that can rapidly diffuse through perforin pores to bind and illuminate nucleic acids in the cytosol and nucleus of the target (5). EGFP-tagged ESCRT proteins were consistently recruited to the site of CTL engagement within 30 to 60 s after PI influx (Fig. 1, A and B). EGFP-Tsg101 and EGFP-Chmp4b in target cells accumulated at the cytolytic synapse after PI influx in 25 of 27 (92.6%) and 31 of 33 (93.9%) of conjugates monitored, respectively, compared with a cytosolic EGFP control, which was not recruited (Fig. 1C and movies S1 to S3). Notably, ESCRT-laden material, presumably membrane fragments, frequently detached from the target cell and adhered to the surface of the CTL (Fig. 1, D and E, and movie S2). We observed this phenomenon in ~60% of conjugates imaged in which targets expressed EGFP-Tsg101 or EGFP-Chmp4b (17 of 27 and 20 of 33 conjugates, respectively; Fig. 1D). Shedding of ESCRT-positive membrane from the cell after repair occurs after laser-induced plasma membrane wounding (67). Plasma membrane fragments shed from the target cell into the synaptic cleft likely contain ligands for CTL-resident receptors. Target cell death would separate the CTL and target, revealing target-derived material on the CTL surface.
FIG. 1. Fluorescently tagged ESCRT proteins in targets localize to site of CTL killing after perforin secretion.
(A) Live-cell spinning disk confocal imaging of a fluorescently labeled OT-I CTL (magenta) engaging an MC38 cancer cell expressing EGFP-Tsg101 (green) in media containing 100 μM PI (red). Yellow arrowheads highlight ESCRT recruitment. T-0:00 is the first frame of PI influx into the target cell (time in minutes:seconds). Scale bar, 10 μm. (B) Graph of EGFP-Tsg101 and PI fluorescence intensity at the IS within the target over time, from example in (A). AU, arbitrary units. (C and D) Quantification of CTL-target conjugates exhibiting accumulation of EGFP at the synapse after PI influx (C) or detectable EGFP-labeled material associated with CTL after target interaction (D) (EGFP condition: N = 22 conjugates in seven independent experiments; EGFP-Tsg101 condition: N = 27 conjugates in nine independent experiments; EGFP-Chmp4b condition: N = 33 conjugates in 24 independent experiments). (E) Live-cell spinning disk confocal imaging of OT-I CTL (magenta) killing MC38 expressing EGFP-Chmp4b (green), demonstrating the presence of target-derived EGFP-Chmp4b material (yellow arrowheads) associated with CTL membrane after a productive target encounter. T-0:00 is the first frame of PI influx into the target cell. Scale bar, 10 μm.

3D cryo-SIM and FIB-SEM imaging of CTLs caught in the act of killing target cells

Although live-cell imaging indicated that ESCRT complexes were rapidly recruited at sites of T cell–target cell contact, light microscopy alone is of insufficient resolution to establish that this event occurred at the immunological synapse (IS). We thus sought to capture a comprehensive view of the IS in the moments immediately after secretion of lytic granules. We used cryo–fluorescence imaging followed by correlative focused ion beam–scanning electron microscopy (FIB-SEM), which can achieve isotropic three-dimensional (3D) imaging of whole cells at 8-nm resolution or better (1113). To capture the immediate response of target cells after perforin exposure, we developed a strategy whereby cryo-fixed CTL-target conjugates were selected shortly after perforation, indicated by the presence of a PI gradient in the target (fig. S1A). In live-cell imaging experiments, PI fluorescence across the nucleus of SIINFEKL-pulsed ID8 target cells began as a gradient and became homogeneous 158 ± 64 s, on average, after initial PI influx (N = 31 conjugates; fig. S1, B and C, and movie S4). Thus, fixed CTL-target conjugates that exhibited a gradient of PI across the nucleus would have been captured within ~3 min of perforin exposure.
Coverslips of CTL-target conjugates underwent high-pressure freezing and were subsequently imaged with wide-field cryogenic fluorescence microscopy followed by 3D cryo–structured illumination microscopy (3D cryo-SIM) performed in a customized optical cryostat (14). We selected candidate conjugates for FIB-SEM imaging on the basis of whether a gradient of PI fluorescence was observed across the nucleus of the target emanating from an attached CTL (movie S5). FIB-SEM imaging of the CTL-target conjugate at 8-nm isotropic voxels resulted in a stack of >10,000 individual electron microscopy (EM) images. The image stack was then annotated using a human-assisted machine learning–computer vision platform to segment the plasma membranes of each cell along with cell nuclei and various organelles (https://ariadne.ai/).
We captured four isotropic 3D 8-nm-resolution EM datasets of CTLs killing cancer cells moments after the secretion of lytic granule contents (Fig. 2A and movie S6). Semiautomated segmentation of the cell membranes, nuclei, lytic granules, Golgi apparatus, mitochondria, and centrosomes of the T cells allow for easier visualization and analysis of the 3D EM data. All FIB-SEM datasets and segmentations can be explored online at https://openorganelle.janelia.org (see links in the supplementary materials). Reconstructed views of the segmented data clearly demonstrate the polarization of the centrosome, Golgi apparatus, and lytic granules to the IS—all of which are hallmarks of CTL killing [Fig. 2A, i to iii, and movie S6, time stamp (TS) 1:33] (1516). On the target cell side, we noted cytoplasmic alterations consistent with cell damage including enhanced electron density of mitochondria adjacent to the IS (fig. S2A). Close visual scanning of the postsynaptic target cell membrane in the raw EM data failed to reveal obvious perforin pores, which have diameters (16 to 22 nm) close to the limit of resolution for this technique (17).
FIG. 2. Eight-nm-resolution 3D FIB-SEM imaging of whole CTL-target conjugate.
(A) 3D rendering of segmented plasma membrane predictions derived from isotropic 8-nm-resolution FIB-SEM imaging of a high-pressure frozen OT-I CTL (red) captured moments after secretion of lytic granules toward a peptide-pulsed ID8 ovarian cancer cell (blue). (i) Side-on sliced view corresponding to the gray horizontal line within the inset box in (A). Seen here are 3D renderings of the segmented plasma membrane of the cancer cell (blue) as well as the CTL plasma membrane (red), centrosome (gold), Golgi apparatus (cyan), lytic granules (purple), mitochondria (green), and nucleus (gray). (ii and iii) A zoomed-in view from the dashed white box in (i) shows the details of the IS (ii) and a single corresponding FIB-SEM slice docked onto the segmented data (iii). (B) Single top-down FIB-SEM slice showing overlaid target cell (blue) and CTL (red) segmentation. (i) Zoomed-in view from dashed white box in (B) details the intercellular material (IM) (gray) between the CTL and target at the IS. (C) Zoomed-in image of a 3D rendering of the surface of the target cell plasma membrane (white) opposite the intercellular material (IM) at the IS. Yellow arrowheads mark plasma membrane buds protruding into the synaptic cleft. (i and ii) Accompanying images demonstrate the orientation of the view in (C) with the rendering of the CTL (red) present (i) and removed (ii), and the dashed yellow box in (ii) indicates the area of detail shown in (C).
The segmentation of the two cells illustrates the detailed topography of the plasma membrane of the CTL and target at the IS (fig. S2B). The raw EM and segmentation data reveal a dense accumulation of particles, vesicles, and multilamellar membranous materials, which crowd the synaptic cleft between the CTL and the target (Fig. 2B and movie S6, TS 0:40 to 0:50). The source of this intercellular material (IM) was likely in part the lytic granules because close inspection revealed similar particles and dense vesicles located within as-yet-unreleased granules (fig. S2C). To determine whether some of the membranous material within the intercellular space might also have been derived from the target cell, we examined the surface topology of the postsynaptic target cell. We noted multiple tubular and bud-like protrusions of the target cell membrane that extended into the synaptic space; thus, at least some of the membrane structures observed were still in continuity with the target cell (Fig. 2C and movie S6, TS 0:58 to 1:11). ESCRT proteins have been shown to generate budding structures in the context of plasma membrane repair (6), which led us to next assess where target-derived ESCRT proteins are distributed in the context of the postsecretion IS.
To map the localization of target-derived ESCRT proteins onto a high-resolution landscape of the IS, we captured three FIB-SEM datasets that have associated 3D cryo-SIM fluorescence data for mEmerald-Chmp4b localization (Fig. 3A, fig. S3, and movie S7). This correlative light and electron microscopy (CLEM) revealed that mEmerald-Chmp4b expressed in the target cell was specifically recruited to the target plasma membrane opposite the secreted IM (Fig. 3, B and C). The topography of the plasma membrane at the site of ESCRT recruitment was markedly convoluted, exhibiting many bud-like projections (movie S7, TS 0:37 to 0:40). mEmerald-Chmp4b fluorescence also overlapped with some vesicular structures in the intercellular synaptic space (Fig. 3C). Together, the live-cell imaging and the 3D cryo-SIM and FIB-SEM CLEM demonstrate the localization of ESCRT proteins at the synapse that was the definitive site of CTL killing and was thus spatially and temporally correlated to perforin secretion. These data implicate the ESCRT complex in the repair of perforin pores.
FIG. 3. Correlative 3D cryo-SIM and FIB-SEM reveal localization of target-derived ESCRT within the cytolytic IS.
(A) Three example datasets showing correlative 3D cryo-SIM and FIB-SEM imaging of OT-I CTLs (red) captured moments after secretion of lytic granules toward peptide-pulsed ID8 cancer cells (blue) expressing mEmerald-Chmp4b (green fluorescence). (B and C) Single FIB-SEM slices corresponding to the orange boxes in (A), overlaid with CTL and cancer cell segmentation (B) or correlative cryo-SIM fluorescence of mEmerald-Chmp4b derived from the target cell (C).

Function of ESCRT proteins in repair of perforin pores

We next investigated whether ESCRT inhibition could enhance the susceptibility of target cells to CTL-mediated killing. Prolonged inactivation of the ESCRT pathway is itself cytotoxic (9). We thus developed strategies to ablate ESCRT function that would allow us a window of time to assess CTL killing (fig. S4). We used two approaches to block ESCRT function: CRISPR knockout of the Chmp4b gene or overexpression of VPS4aE228Q (E228Q, Glu228 → Gln), a dominant-negative kinase allele that impairs ESCRT function (fig. S4, A to C) (10). We took care to complete our assessment of target killing well in advance of spontaneous target cell death (fig. S4D).
We tested the capacity of OT-I CTLs to kill targets presenting one of four previously characterized peptides that demonstrate a range of potencies at stimulating the OT-I TCR: SIINFEKL (N4), the cognate peptide, and three separate variants (in order of highest to lowest affinity), SIITFEKL (T4), SIIQFEHL (Q4H7), and SIIGFEKL (G4) (1819). Target cells were pulsed with peptide, washed, transferred to 96-well plates, and allowed to adhere before the addition of OT-I CTLs. Killing was assessed by monitoring the uptake of a fluorogenic caspase 3/7 indicator (Fig. 4, A to D, and fig. S5A). Killing was significantly more efficient in ESCRT-inhibited target cells for both CRISPR depletion of Chmp4b (Fig. 4, A to C) and expression of the dominant-negative VPS4aE228Q (Fig. 4D). The difference in killing between the ESCRT-inhibited and control cells was greater when the lower-potency T4, Q4H7, and G4 peptides were used. Nevertheless, ESCRT inhibition moderately improved killing efficiency even in the case of the high-potency SIINFEKL peptide. ESCRT inhibition had no effect on MHC class I expression on the surface of target cells (fig. S5B). Thus, ESCRT inhibition could sensitize target cells to perforin- and granzyme-mediated killing, especially at physiologically relevant TCR-peptide MHC affinities.
FIG. 4. ESCRT inhibition enhances susceptibility of cancer cells to CTL killing and recombinant lytic proteins.
(A) Representative time-lapse data of killing of peptide-pulsed Chmp4b knockout (KO) or control B16-F10 cells by OT-I CTLs. Affinity of the pulsed peptide to OT-I TCR decreases from left to right. Error bars indicate SDs. (B) Images extracted from T4 medium-affinity peptide condition show software-detected caspase 3/7+ events in control and Chmp4b KO conditions. (C and D) Data representing the 4-hour time point of assays measuring OT-I T cells killing either Chmp4b KO (C) or VPS4 dominant-negative (D) target cells with matched controls. Error bars indicate SDs of data. Data are representative of at least three independent experimental replicates. pMHC, peptide-MHC; HA, hemagglutinin. (E and F) Determination of sublytic dose of Prf. B16-F10 cells expressing VPS4a (WT or E228Q) were exposed to increasing concentrations of Prf. Cell viability was determined by morphological gating (E). FSC, forward scatter; SSC, side scatter. (G and H) B16-F10 cells expressing VPS4a (WT or E228Q) were exposed to a sublytic dose of Prf in combination with increasing concentrations of recombinant GZMB (rGZMB). Cell death was determined by Annexin V–allophycocyanin (APC) staining (G). Controls include a condition with no perforin and 5000 ng/ml rGZMB and sublytic perforin with no rGZMB. Graphs in (F) and (H) represent the means of three experiments, and error bars indicate SDs. Statistical significance was determined by multiple unpaired t tests with alpha = 0.05. ns, not significant; *P < 0.05; **P < 0.01; ***P < 0.001.
We next directly tested the effects of ESCRT inhibition when target cells were exposed to both recombinant perforin (Prf) and granzyme B (GZMB), the most potently proapoptotic granzyme in humans and mice (20). Prf alone at high concentrations can lyse cells (4), so we first determined a sublytic Prf concentration that would temporarily permeabilize the plasma membrane but permit the cells to recover. B16-F10 cells expressing either VPS4aWT (WT, wild-type) or VPS4aE228Q were exposed to a range of Prf concentrations in the presence of PI, and cell viability and PI uptake were assessed using flow cytometry. Cells that expressed dominant-negative VPS4aE228Q were more sensitive to Prf alone than ESCRT-competent cells (Fig. 4, E and F). At 160 ng/ml Prf, there was no significant difference in cell viability for either condition. Cells in the live gate that were PI+ had been permeabilized by Prf but recovered. Although the percentage of PI+ live cells was similar under both sets of conditions, the mean fluorescence intensity of PI was higher in live ESCRT-inhibited cells (fig. S6). A delay in plasma membrane resealing could account for this difference.
We reasoned that delaying perforin pore repair might also enhance GZMB uptake into the target. ESCRT-inhibited cells were more sensitive to combined perforin-GZMB when cell death was measured by Annexin V staining (Fig. 4, G and H). Similar results were observed when these experiments were repeated with a murine lymphoma cancer cell line (fig. S7). The observation that ESCRT-inhibited target cells are more sensitive to both CTL-secreted and Prf-GZMB supports the hypothesis that the ESCRT pathway contributes to membrane repair after Prf exposure.
Escaping cell death is one of the hallmarks of cancer. Our findings suggest that ESCRT-mediated membrane repair of perforin pores may restrict accessibility of the target cytosol to CTL-secreted granzyme, thus promoting survival of cancer-derived cells under cytolytic attack. Although other factors may contribute to setting the threshold for target susceptibility to killing, the role of active repair of perforin pores must now be considered as a clear contributing factor.


We thank members of the Mellman laboratory for advice, discussion, and reagents; B. Haley for assistance with plasmid construct design; the Genentech FACS Core Facility for technical assistance; S. Van Engelenburg of Denver University for invaluable discussions and guidance; A. Wanner, S. Spaar, and the Ariande AI AG (https://ariadne.ai/) for assistance with FIB-SEM segmentation, CLEM coregistration, data presentation, and rendering; D. Bennett of the Janelia Research Campus for assisting with data upload to https://openorganelle.janelia.org; and the Genentech Postdoctoral Program for support.
Funding: A.T.R. and I.M. are funded by Genentech/Roche. C.S.X., G.S., A.W., D.A., N.I., and H.F.H. are funded by the Howard Hughes Medical Institute (HHMI).

Please look for a Followup Post concerning “Developing a Pharmacovigilence Framework for Engineered T-Cell Therapies”



  1. Ertl HC, Zaia J, Rosenberg SA, June CH, Dotti G, Kahn J, Cooper LJ, Corrigan-Curay J, Strome SE: Considerations for the clinical application of chimeric antigen receptor T cells: observations from a recombinant DNA Advisory Committee Symposium held June 15, 2010. Cancer research 2011, 71(9):3175-3181.
  2. Morgan RA, Yang JC, Kitano M, Dudley ME, Laurencot CM, Rosenberg SA: Case report of a serious adverse event following the administration of T cells transduced with a chimeric antigen receptor recognizing ERBB2. Molecular therapy : the journal of the American Society of Gene Therapy 2010, 18(4):843-851.
  3. Kandalaft LE, Powell DJ, Jr., Coukos G: A phase I clinical trial of adoptive transfer of folate receptor-alpha redirected autologous T cells for recurrent ovarian cancer. Journal of translational medicine 2012, 10:157.

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Molecular Profiling in Cancer Immunotherapy: Debraj GuhaThakurta, PhD

Pancreatic Cancer: Genetics, Genomics and Immunotherapy

$20 million Novartis deal with ‘University of Pennsylvania’ to develop Ultra-Personalized Cancer Immunotherapy

Upcoming Meetings on Cancer Immunogenetics

Tang Prize for 2014: Immunity and Cancer

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Larry H Bernstein, MD, FCAP, reporter and curator


The amount of success in stem cell research and recent successes is notable.

GEN News  Dec 5, 2013
Stem Cell Leaders Call for Human Embryome Project

Just as an international consortium was formed to map and sequence the human genome, now a group of stem cell and regenerative medicine scientists say it’s critical that such an effort be ramped up to do a similar project focused on the human embryome.

This was the key message of a panel discussion, “From Mapping the Genome to Mapping the Embryome: The Urgent Need for an International Initiative,” moderated by Michael West, Ph.D., CEO of Biotime. It took place at the World Stem Cell Summit, which is taking place this week in San Diego.

“It is becoming increasingly clear in regenerative medicine that pluripotent stem cells, embryonic stem cells, and IPs cells will be as fundamentally important to medicine as was DNA. Maybe even bigger because you can genetically engineer these cells,” said Dr. West.

Dr. West and his colleagues adamantly believe that there needs to be a large international effort aimed at mapping the cellular and molecular basis of all human life starting with the fertilized egg and working its way up to the body of the adult. This is what it is termed the embryome.

“The opportunity presented by pluripotent stem cells to manufacture for the first time in the history of medicine all of the cellular components of the human body on an industrial scale is at once both an opportunity and a challenge,” said Dr. West. “The opportunity is to build a new field we call regenerative medicine in which many currently incurable diseases are treated with cells capable of regenerating tissues afflicted with disease. The challenge relates to the complexity of the cell types in the body and our ability to manufacture products with precisely defined compositions for human clinical use.”

Dr. West went on to say that to get these different types of stem cells into the clinic, and approved by the FDA, researchers will fully need to understand all aspects of the biology of these cells. An identification and understanding of any contaminating cells will also be essential to success in this field. The question to ask is “What is in the syringe?”

Unlike recombinant DNA, continued Dr. West, the contaminants in pluripotent stem cells are alive and may make things that are undesirable at the intended point of therapy. For example, you might have a bioreactor full of cells that are making heart muscle to regenerate heart function in a patient. But you have to be careful that your cells are not contaminated with neural crest cells from the head area which could generate a tooth along with the heart muscle.

“These contaminants, if you do not remove them, can lead to years of delay in filing an IND and a runup in costs as you try to identify these cells,” explained Dr. West.

The major problem in identifying them, according to Dr. West, is that no one has ever mapped the molecular markers or even a rudimentary cell ontology tree, i.e., mapped out the tree from the fertilized egg to the cells of the human body.

“If [there were] a detailed map of all the cellular and molecular components of life from the fertilized egg to adulthood, and then databased in a manner to the information in the human genome, medicine would be the true beneficiary,” added Dr. West. “That’s why we have made this call for an international initiative.”

Also, watch our video “A Brief History of Stem Cells” to see a timeline spanning over 60 years of stem cell research.

Mary Ann Liebert Wins Stem Cell Education Award

Mary Ann Liebert, president and CEO of Mary Ann Liebert Inc., and publisher of GEN, was presented with the Stem Cell Education Award by the Genetics Policy Institute. The award was given during a ceremony at dinner which took place at the World Stem Cell Summit, which is being held in San Diego this week.

Liebert was cited for her outstanding “work in educating patients, researchers, and the broader stem cell community, and in raising the standard in medical research journalism.” Among the seventy journals the Liebert company publishes is the peer-reviewed Stem Cells and Development.

In her acceptance speech Liebert told the audience that she was extremely gratified in being so recognized and thanked the entire staff at her company for their dedication in helping to promote excellence in medical publishing.

In his introductory remarks during the award ceremony GEN’s long-time editor in chief John Sterling noted that Mary Ann always encourages her editors and writers “to inform, enlighten when they can, and educate as much as possible.”

Sterling added that while she started her company 33 years ago her vision for her publications remains the same: “to help advance our knowledge of science and medicine in the best ways possible.”


Neural Precursors “Cure MS” in Mice

During a session at the this week’s World Stem Cell Summit in San Diego, an international research team described an “astonishing” experiment in which a mouse model of multiple sclerosis was able to virtually totally recover and move normally after being transplanted with human neural precursor cells (hNPC). The scientists were able to show almost full recovery in the mice up to six months later.

The investigators, led by Jeanne Loring, Ph.D., from the Scripps Research Institute, included scientists from the University of California, Irvine and a group from Australia.

“Our goal was to demonstrate cell therapy for MS,” Dr. Loring told the audience.

According to Ronald Coleman, a graduate student working with Dr. Loring and who is at UC-Irvine, the team used mice infected with a neurotropic JHM variant of mouse hepatitis virus (JHMV) as a model for MS. They injected hNPCs derived from human pluripotent stem cells (hPSC) into the mice to explore treatment options for the disease.

The results were indeed astonishing, said Dr. Loring. Non-control mice were able to move about in a manner that can be described as consistent and long lasting. T-cell proliferation was reduced and T regulatory cell induction took place. The spinal cords of the mice not only did not undergo further demyelination but actually exhibited remyelination. The control mice dragged their legs around when they tried to move.

“The only problem was that the hNPCs themselves are not directly responsible for the cure. They are not even there when the mice start walking,” explained Dr. Loring. “Those cells are rejected after seven days and we start to see a therapeutic response in three weeks.”

Both Dr. Loring and Coleman believe that the hNPCs are secreting proteins, like cytokines, that do the actual repair work in the CNS of the mice.

“We identified a set of candidate proteins secreted by hNPCs and not by undifferentiated pluripotent stem cells,” continued Dr. Loring, who said the team plans to continue building on this initial research.


World Stem Cell Summit: December 4, 2013 Update

GEN is on the scene at the World Stem Cell Summit in San Diego. Here are some highlights from the conference so far:

Bernard Siegel, J.D., founder and co-chair of the World Stem Cell Summit (WSCS) and executive director of Genetics Policy Institute, today welcomed attendees of WSCS 2013, being held December 4–6, in San Diego, CA.

“Stem cell science represents, to those afflicted with chronic disease, a vehicle for modeling disease and therapeutic development,” states Siegel in World Stem Cell Report 2013, a supplement to Stem Cells and Development (2013;22;Suppl1). “The field is a true scientific revolution and reflects the transformative power of hope, a powerful engine for progress.”

“The future is here now,” says Mahendra Rao, M.D., Ph.D., director, NIH Center for Regenerative Medicine, who delivered a plenary keynote and moderated the plenary panel discussion, “How Stem Cells are Transforming Medicine.” Cell therapies have been used to treat people safely and effectively; the technical barriers have been addressed. The challenge now is to reduce the cost of manufacturing. To drive routine adoption of cell therapy it must be cost effective and must demonstrate more than incremental benefit, according to Dr. Rao.

Professor Teruo Okano, Ph.D., Tokyo Women’s Medical University, described his group’s Cell Sheet Tissue Engineering strategy that involves enzymatic membrane disruption during cell harvesting and growth of an autologous cell sheet for transplantation on an “intelligent surface” that reversibly changes properties from hydrophobic to hydrophilic with a reversible in temperature from 37°C to 20°C. Dr. Okano further described the development of an automatic tissue factory and thick tissue evaluation system for fully automated, industrialized GMP cell processing.

Andre Terzic, M.D., Ph.D., Center for Regenerative Medicine, Mayo Clinic, noted during the opening session of the WSCS that “the Mayo Clinic has embraced regenerative medicine as a strategy for the future of medicine,” and he described their blueprint for moving from knowledge to delivery of treatments and procedures. Education is a critical dimension of this process. Another important component, according to Dr. Terzic, is the Regenerative Medicine Biotrust, in which “the patient is the center of the solution” to develop combinations of diagnostics and therapeutics and conduct clinical trials.

Regardless of the outcomes of current or future clinical trials, “I would argue that we have already seen breakthroughs,” said Evan Snyder, Ph.D., Sanford-Burnham Medical Research Institute, as stem cells “have completely changed the way medicine thinks about disease and development.” They have led to new views on plasticity and regeneration and the development of different types of drug targets.

WSCS 2013 is organized by the Genetics Policy Institute (GPI), California Institute for Regenerative Medicine (CIRM), Institute for Integrated Cell-Material Sciences at Kyoto University (iCeMS), Mayo Clinic, Sanford-Burnham Medical Research Institute, and The Scripps Research Institute. Mary Ann Liebert, Inc. publishers and Genetic Engineering & Biotechnology News (GEN) are sponsors of the summit.

Drug Testing Should Be with Human iPS Cells
Fri, 12/06/2013 – drug discovery & development  (DDD)

Once established such neural stem cells can be used to continuously generate neurons for drug testing and disease modeling. Depicted is an immunofluorescence staining where proteins characteristic of neural stem cells are labeled with fluorescing antibodies (Nestin in green, Dach1 in red). (Source: Jerome Mertens / Uni Bonn)Once established such neural stem cells can be used to continuously generate neurons for drug testing and disease modeling. Depicted is an immunofluorescence staining where proteins characteristic of neural stem cells are labeled with fluorescing antibodies (Nestin in green, Dach1 in red). (Source: Jerome Mertens / Uni Bonn)Why do certain Alzheimer medications work in animal models but not in clinical trials in humans? A research team from the University of Bonn and the biomedical enterprise Life & Brain GmbH has been able to show that results of established test methods with animal models and cell lines used up until now can hardly be translated to the processes in the human brain. Drug testing should therefore be conducted with human nerve cells, conclude the scientists. The results are published by Cell Press in the journal Stem Cell Reports.

In the brains of Alzheimer’s patients, deposits form that consist essentially of beta-amyloid and are harmful to nerve cells. Scientists are therefore searching for pharmaceutical compounds that prevent the formation of these dangerous aggregates. In animal models, certain non-steroidal anti-inflammatory drugs (NSAIDs) were found to a reduced formation of harmful beta-amyloid variants. Yet, in subsequent clinical studies, these NSAIDs failed to elicit any beneficial effects.

“The reasons for these negative results have remained unclear for a long time”, said Oliver Brüstle, director of the Institute for Reconstructive Neurobiology of the University of Bonn and CEO of Life & Brain GmbH. “Remarkably, these compounds were never tested directly on the actual target cells—the human neuron”, added lead author Jerome Mertens of Brüstle’s team, who now works at the Laboratory of Genetics in La Jolla (USA). This is because, so far, living human neurons have been extremely difficult to obtain. However, with the recent advances in stem cell research it has become possible to derive limitless numbers of brain cells from a small skin biopsy or other adult cell types.

Scientists transform skin cells into nerve cells

Now a research team from the Institute for Reconstructive Neurobiology and the Department of Neurology of the Bonn University Medical Center together with colleagues from the Life & Brain GmbH and the University of Leuven (Belgium) has obtained such nerve cells from humans. The researchers used skin cells from two patients with a familial form of Alzheimer’s Disease to produce so-called induced pluripotent stem cells (iPS cells), by reprogramming the body’s cells into a quasi-embryonic stage. They then transformed the resulting iPS cells into nerve cells.

Using these human neurons, the scientists tested several compounds in the group of NSAIDs. As control, the researchers used nerve cells they had obtained from iPS cells of donors who did not have the disease. Both in the nerve cells obtained from the Alzheimer’s patients and in the control cells, the NSAIDs that had previously tested positive in the animal models and cell lines typically used for drug screening had practically no effect: The values for the harmful beta-amyloid variants that form the feared aggregates in the brain remained unaffected when the cells were treated with clinically relevant dosages of these compounds.

Metabolic processes in animal models differ from humans

“In order to predict the efficacy of Alzheimer drugs, such tests have to be performed directly on the affected human nerve cells”, concluded Brüstle’s colleague Philipp Koch, who led the study. Why do NSAIDs decrease the risk of aggregate formation in animal experiments and cell lines but not in human neurons? The scientists explain this with differences in metabolic processes between these different cell types. “The results are simply not transferable”, says Koch.

The scientists now hope that in the future, testing of potential drugs for the treatment of Alzheimer’s disease will be increasingly conducted using neurons obtained from iPS cells of patients. “The development of a single drug takes an average of ten years”, said Brüstle. “By using patient-specific nerve cells as a test system, investments by pharmaceutical companies and the tedious search for urgently needed Alzheimer medications could be greatly streamlined”.

Date: November 6, 2013
Source: University of Bonn


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