UPDATED Postmarketing Safety or Effectiveness Data Needed: The 2013 paper was funded by the firm Sarepta Therapeutics, sellers of eteplirsen, a surge in its shares seen after the approval. Eteplirsen will cost patients around $300,000 a year.

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UPDATED Postmarketing Safety or Effectiveness Data Needed: The 2013 paper was funded by the firm Sarepta Therapeutics, sellers of eteplirsen, a surge in its shares seen after the approval. Eteplirsen will cost patients around $300,000 a year.

September 22, 2016 by 2012pharmaceutical

UPDATED Postmarketing Safety or Effectiveness Data Needed: The 2013 paper was funded by the firm Sarepta Therapeutics, sellers of eteplirsen, a surge in its shares seen after the approval. Eteplirsen will cost patients around $300,000 a year.

Curator: Aviva Lev-Ari, PhD, RN

UPDATED on 5/15/2023

FDA advisers narrowly vote in favor of Sarepta’s DMD gene therapy

By Max Bayer May 12, 2023 07:09pm

FDA advisers have narrowly voted in favor of Sarepta Therapeutics’ gene therapy for patients with Duchenne muscular dystrophy (DMD), a stunning decision that runs counter to regulators who expressed skepticism heading into the meeting.

Experts from the Cellular, Tissue, and Gene Therapies Advisory Committee narrowly voted 8 to 6 that the benefit-risk profile of SRP-9001 was strong enough to support accelerated approval even as questions about the gene therapy’s efficacy linger. No members of the committee abstained. SRP-9001 was developed to treat ambulatory patients with a DMD gene mutation.

https://www.fiercebiotech.com/biotech/fda-sarepta-advisors-meeting-dmd-gene-therapy-vote-against

Advisers were tasked with considering four discussion topics about SRP-9001 that centered on the available data on the treatment, the benefit-risk profile of administering it and the implications of allowing the company to use an ongoing phase 3 trial as a confirmatory study. There was little alignment between Sarepta and the FDA’s interpretation of the data, forcing advisers to break the tie.

“I think we owe it to the patients to help them intervene,” said committee member and consumer representative Kathleen O’Sullivan-Fortin, who voted in favor. Others expressed confidence in the safety profile of the gene therapy even amid concerns about the efficacy.

FDA shocks Sarepta, ordering AdComm for DMD gene therapy in sudden change of heart

Sarepta argued that a surrogate endpoint quantifying the expression of micro-dystrophin protein in patients’ muscles was an adequate biomarker to predict clinical benefit and grant accelerated approval. The company cited a natural history study as evidence that correcting the expression addresses the root cause of DMD. The FDA has for years been wary of the proposed biomarker, suggesting as far back as 2018 that Sarepta reconsider the endpoint.

Some of the concerns raised by both committee members and the FDA were aimed at Sarepta’s manufacturing of SRP-9001, which changed between the second and third clinical trials. The new process, which uses a lower percentage of full capsid, is what Sarepta is using in its accelerated approval application. The agency cautioned this could reduce efficacy and increase the risk of side effects. It also wasn’t the process used in Sarepta’s most detailed clinical trial, part of Study 102.

That trial was the only randomized, placebo-controlled study of the gene therapy conducted to date. The trial found that there was not a statistically significant change in functional motor ability between treated patients and placebo as assessed by a common functional rating scale for DMD. Sarepta argued that treated patients had a numerically greater score at all time points, but the FDA concluded those figures were within the bounds of uncertainty, “which is also demonstrated by the lack of even a trend toward statistical significance.”

Sarepta pointed to a post hoc analysis to show that the results varied by age, however, with treated patients ages 4 to 5 showing improvement compared to placebo while 6- to 7-year-old patients had worse function scores than placebo. Sarepta used external control groups from natural history studies to prove a larger benefit between treated and untreated patients across the company’s studies to date. But the FDA said Friday that the natural history data are “challenging to interpret.”

https://www.fiercebiotech.com/biotech/fda-sarepta-advisors-meeting-dmd-gene-therapy-vote-against

UPDATED on 8/18/2019

Sarepta Duchenne drug rejected by FDA in surprise setback

Dive Brief:

In an unexpected decision, the Food and Drug Administration rejected Sarepta Therapeutics’ experimental drug for Duchenne muscular dystrophy, issuing on Monday a Complete Response Letter to the rare disease biotech.

According to Sarepta, the agency cited in its refusal infection risk tied to the drug’s delivery as well as preclinical signs of kidney toxicity. Called Vyondys 53, the medicine is designed for roughly 8% of Duchenne patients with a specific genetic mutation.

Shares in Cambridge, Mass.-based Sarepta fell sharply in post-market trading. Approval of the drug was widely anticipated, making the rejection a setback in Sarepta’s ambitions to treat a wider pool of Duchenne patients.

SOURCE

https://www.biopharmadive.com/news/sarepta-surprise-fda-rejection-duchenne-vyondys-53/561200/

On September 19, the FDA okayed eteplirsen to treat Duchenne muscular dystrophy (DMD), a rare genetic disorder that results in muscle degeneration and premature death. Several of its top officials disagreed with the drug’s approval, questioning how beneficial it will be for patients, as Forbes, MedPage Today and others reported.

http://retractionwatch.com/2016/09/21/amid-controversial-sarepta-approval-decision-fda-head-calls-for-key-study-retraction/

Factors at play for FDA Approval of eteplirsen

the help of the families of young boys with Duchenne muscular dystrophy, emotional scenes from these families who have campaigned for so long
an executive team from Sarepta who wouldn’t give up,

Ed Kaye, Sarepta, CEO – EK: It’s all about resilience. One of the things we’ve had is a group of people of like minds and anytime one of us gets down, somebody else is there to pick you up. One of the things we’ve always done is: Every time we’ve felt sorry for ourselves, we just need to think about those patients and what they go through. Our struggles in comparison very quickly become meaningless. You end up saying to yourself: What am I complaining about? Quit whining; get up and do your job.

and

3. an emerging new philosophy from some within the FDA, eteplirsen, now Exondys 51, was approved in patients with a confirmed mutation of the dystrophin gene amenable to exon 51 skipping.

http://www.fiercebiotech.com/biotech/sarepta-ceo-ed-kaye-fda-courage-nice-and-resilience?utm_medium=nl&utm_source=internal&mrkid=993697&mkt_tok=eyJpIjoiTXpBeU56aGpNREV3T1RZMiIsInQiOiJIM2poTkVOQ0N6YmxaenVHZDM1RlVvbTFmRkdwZGdxQ0pmYXNVOG5PKzRyenFXTkRMV0dcL3l0bVBPNkJ2NFV3Rnc3bWVFVnUwMCs3YVhWeVhvRkkrUU5FMFJ1RndSQTlHWFRnQmFTbUo3ODg9In0%3D

9/19/2016

FDA grants accelerated approval to first drug for Duchenne muscular dystrophy

The accelerated approval of Exondys 51 is based on the surrogate endpoint of dystrophin increase in skeletal muscle observed in some Exondys 51-treated patients. The FDA has concluded that the data submitted by the applicant demonstrated an increase in dystrophin production that is reasonably likely to predict clinical benefit in some patients with DMD who have a confirmed mutation of the dystrophin gene amenable to exon 51 skipping. A clinical benefit of Exondys 51, including improved motor function, has not been established. In making this decision, the FDA considered the potential risks associated with the drug, the life-threatening and debilitating nature of the disease for these children and the lack of available therapy.

The FDA granted Exondys 51 fast track designation, which is a designation to facilitate the development and expedite the review of drugs that are intended to treat serious conditions and that demonstrate the potential to address an unmet medical need. It was also granted priority review and orphan drug designation. Priority review status is granted to applications for drugs that, if approved, would be a significant improvement in safety or effectiveness in the treatment of a serious condition. Orphan drug designation provides incentives such as clinical trial tax credits, user fee waiver and eligibility for orphan drug exclusivity to assist and encourage the development of drugs for rare diseases.

SOURCE

http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm521263.htm

The viability of this drug approval depends on “to be gathered” Postmarketing safety or effectiveness data, aka follow-up confirmatory trials.

Sarepta CEO Ed Kaye on FDA courage, NICE and resilience

BA: When it comes to flexibility, however, the FDA will likely not be flexible if your drug doesn’t prove the desired efficacy in your longer term postmarketing studies. If at the end of this period your drug doesn’t come through, how easy will it be for you to take this off the market? I don’t think anyone, including the FDA, wants a repeat of what happened in 2011 when Roche saw its breast cancer license for Avastin, which had been approved under an accelerated review, pulled after not being safe or effective enough in the follow-up confirmatory trials. But you face this as a possible scenario.

EK: That’s true, but one of the things we’re trying to do to mitigate that is to obviously, with our ongoing studies, prove the efficacy that the FDA wants to see. And you know, if there is a problem with one study then we’d hope to have other data that are supportive. The other thing we’re doing of course is developing that next-generation chemistry in DMD that could prove more effective, so we could certainly consider using that next-gen chemistry to take our work forward and try and make it better.

We have a lot of shots on goal to make sure we can continue to supply a product for these boys, but there is always a risk. If we can’t show efficacy in the way the FDA wants, then yes they have the option to take it off the market.

Need for follow-up confirmatory trials remains outstanding

FDA’s Postmarketing Surveillance Programs

http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Surveillance/ucm090385.htm

FDA’s Regulations and Policies and Procedures for Postmarketing Surveillance Programs

http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Surveillance/ucm090394.htm

Positions on Sarepta’s eteplirsen Scientific Approach

Gene Editing for Exon 51: Why CRISPR Snipping might be better than Exon Skipping for DMD

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2016/01/23/gene-editing-for-exon-51-why-crispr-snipping-might-be-better-than-exon-skipping-for-dmd/

QUOTE START

Retraction Watch

Tracking retractions as a window into the scientific process

Amid controversial Sarepta approval decision, FDA head calls for key study retraction

with one comment

The head of the U.S. Food and Drug Administration (FDA) has called for the retraction of a study about a drug that the agency itself approved earlier this week, despite senior staff opposing the approval.

In a lengthy report Commissioner Robert Califf sent to senior FDA officials on September 16 — that was made public on September 19 — he called for the retraction of a 2013 study published in Annals of Neurologyfunded by the seller of eteplirsen, which showed beneficial effects of the drug in DMD patients. Califf writes inthe report:

The publication, now known to be misleading, should probably be retracted by its authors.

In a footnote in the report, Califf adds:

In view of the scientific deficiencies identified in this analysis, I believe it would be appropriate to initiate a dialogue that would lead to a formal correction or retraction (as appropriate) of the published report.

The study was not the key factor in the agency’s decision to approve the drug, according to Steve Usdin, Washington editor of the publication BioCentury; still, Usdin told Retraction Watch he is “really surprised” at the call for retraction from top FDA staff, the first he has come across in the last two decades.

The 2013 paper was funded by the firm Sarepta Therapeutics, sellers of eteplirsen, which has seen a surge in its shares after the approval. Eteplirsen will cost patients around $300,000 a year.

DMD affects around 1 in 3,600 boys due to a mutation in the gene that codes for the protein dystrophin, which is important for structural stability of muscles. Eteplirsen is the first drug to treat DMD, and was initially given a green light by Janet Woodcock, director of Center for Drug Evaluation and Research, after a split vote from the FDA’s advisory committee. Despite Califf’s issues with the literature supporting the drug’s use in DMD, he did not overturn Woodcock’s decision, and the agency approved the drug this week.

In 2014, an inspection team visited the Nationwide Children’s Hospital in Columbus, Ohio, where the research was conducted, according to the report. In the report, Ellis Unger, director of the Office of Drug Evaluation I in FDA’s Center for Drug Evaluation, notes:

We found the analytical procedures to be typical of an academic research center, seemingly appropriate for what was simply an exploratory phase 1/2 study, but not suitable for an adequate and well controlled study aimed to serve as the basis for a regulatory action. The procedures and controls that one would expect to see in support of a phase 3 registrational trial were not in evidence.

Specifically, Unger describes concerns about blinding during the experiments, and notes:

The immunohistochemistry images were only faintly stained, and had been read by a single technician using an older liquid crystal display (LCD) computer monitor in a windowed room where lighting was not controlled. (The technician had to suspend reading around mid-day, when brighter light began to fill the room and reading became impossible.)

Unger adds:

Having uncovered numerous technical and operational shortcomings in Columbus, our team worked collaboratively with the applicant to develop improved methods for a reassessment of the stored images…This re-analysis, along with the study published in 2013, provides an instructive example of an investigation with extraordinary results that could not be verified.

Luciana Borio, acting chief scientist at the FDA, is cited in the report saying:

I would be remiss if I did not note that the sponsor has exhibited serious irresponsibility by playing a role in publishing and promoting selective data during the development of this product. Not only was there a misleading published article with respect to the results of Study–which has never been retracted—but Sarepta also issued a press release relying on the misleading article and its findings…As determined by the review team, and as acknowledged by Dr. Woodcock, the article’s scientific findings—with respect to the demonstrated effect of eteplirsen on both surrogate and clinical endpoints—do not withstand proper and objective analyses of the data. Sarepta’s misleading communications led to unrealistic expectations and hope for DMD patients and their families.

Here’s how Sarepta describes the study’s findings in the press release Borio refers to:

Published study results showed that once-weekly treatment with eteplirsen resulted in a statistically significant increase from baseline in novel dystrophin, the protein that is lacking in patients with DMD. In addition, eteplirsen-treated patients evaluable on the 6-minute walk test (6MWT) demonstrated stabilization in walking ability compared to a placebo/delayed-treatment cohort. Eteplirsen was well tolerated in the study with no clinically significant treatment-related adverse events. These data will form the basis of a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for eteplirsen planned for the first half of 2014.

However, Usdin noted that the drug’s approval and the study are two independent events, adding that the 2013 study just “got the ball rolling” for eteplirsen, and the FDA conducted many of its own ~~experiments~~ analyses, as detailed in the newly released report.

Jerry Mendell, the corresponding author of the study (which has so far been cited 118 times, according to Thomson Reuters Web of Science) from Ohio State University in Columbus, told us the allegations were “unfounded” and said the data are “valid.” Therefore, he added, he will not be approaching the journal for a retraction, noting that the FDA asked him hundreds of questions about the paper and audited the trials.

Clifford Saper, the editor-in-chief of Annals of Neurology from the Beth Israel Deaconess Medical Center (which is part of Harvard Medical School), said in an email:

It takes more than a call by a politician for retraction of a paper. It takes actual evidence.

He added:

If the FDA commissioner has, or knows of someone who has, evidence for an error in a paper published in Annals of Neurology, I encourage him to send that evidence to me and a copy to the authors of the article, for their reply. At that point we will engage in a scientific review of the evidence and make appropriate responses.

Linda Lowes, sixth author of the present study, is the last author of a 2016 study in Physical Therapy that was retracted months after publication. Its notice reads:

This article has been retracted by the author due to unintentional deviations in the use of the described modified technique to assess plagiocephaly in the study participants, such that the use of the modified technique cannot be defended for the stated purpose in this population at this time.

Califf was a cardiologist at Duke University during the high-profile scandal of researcher Anil Potti at Duke, which led to more than 10 retractions, settled lawsuits, and medical board reprimands. In 2015, he told TheTriangle Business Journal:

I wish I had gotten myself more involved earlier…There were systems that were not adequate, as we stated. … That was a tough one, I think, for the whole institution.

We’ve contacted the FDA for comment, and will update the post with anything else we learn.

END QUOTE

Correction 9/21/16 10:44 p.m. eastern: When originally published, this post incorrectly reported that Califf was part of an inspection team that visited the Nationwide Children’s Hospital in Ohio, and attributed quotes from Ellis Unger to Califf. We have made appropriate corrections, and apologize for the error.

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