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Clinical Trials Revisited

Posted in Biological Networks, Gene Regulation and Evolution, Biomarkers & Medical Diagnostics, CANCER BIOLOGY & Innovations in Cancer Therapy, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, FDA Regulatory Affairs, Genome Biology, International Global Work in Pharmaceutical, Molecular Genetics & Pharmaceutical, Personalized and Precision Medicine & Genomic Research, Pharmaceutical Industry Competitive Intelligence, Technology Transfer: Biotech and Pharmaceutical, tagged , , , , , , , , , , , on April 3, 2013| 1 Comment »

Larry H Bernstein, MD, FCAP
Pharmaceutical Intelligence

UPDATED 4/23/2020:  New Design for Phase 1 pediatric oncology trials to expedite dose escalation studies.

Clinical Trials Revisited

http://pharmaceuticalintelligence.com/2013/04/03/clinical-trials-revisit/

Cancer Clinical Trials of Tomorrow

Advances in genomics and cancer biology will alter the design of human cancer studies

By Tomasz M. Beer | April 1, 2013   The Scientist
We stand on the cusp of significant change in the fundamental structure of cancer clinical trials, as the emphasis begins to shift from large-scale studies of relatively unselected patients to smaller studies testing more narrowly targeted therapies in molecularly characterized populations.
The previous (and still current) generation of trials established the cancer treatment standards used today. Trials that demonstrated the value of combination chemotherapy in the adjuvant treatment of breast cancer are an excellent example. Meticulous development of treatment regimens through Phase 1 and Phase 2 trials, followed by large-scale comparisons of the new regimens to established treatment protocols, have defined the modern practice of oncology for the last 4 decades. Future cancer clinical trials will be very different from those of the past, adopting a more personalized, sometimes called “precision,” approach.
It is, of course, not entirely true that past clinical trials did not include efforts to target treatments to the right patients. Where possible, targeted therapies are already being implemented. Using the presence of endocrine receptors to guide endocrine therapy for breast cancer was one of the first forays into molecular selection of patients. Unfortunately, the ability to select subgroups of patients for study has been severely curtailed by a still-limited knowledge of human cancer biology.
This is rapidly changing, however, thanks to advances in genomics and comprehensive cancer biology research over the last decade. Large-scale efforts, such as The Cancer Genome Atlas, are comprehensively defining many of the crucial molecular characteristics of human malignancies by illuminating genetic alterations that are clinically and biologically important, and which, by virtue of their functional roles, are viable targets for cancer treatment. At the same time, the ability to design small-molecule inhibitors of specific cancer targets is rapidly accelerating. In 2011, two new agents exemplified the power of these trends: crizotinib was approved for the treatment of lung cancers that harbor a specific mutation in the ALK gene, and vemurafenib was approved for the treatment of melanomas with a specific BRAF mutation. In both cases, the drugs were approved along with companion diagnostic tests that identify patients with the target mutation, who are therefore likely to benefit from treatment.

Smaller, more precise trials ahead

Clinical trials are being transformed by these trends. It will not happen overnight, as the knowledge of cancer biology and the availability of targeted agents are uneven. Unselected populations of patients will still be studied, but it is inevitable that there will be a rise in the number of trials that incorporate molecular tumor testing prior to treatment, with treatment selection informed by the molecular features of each individual’s cancer. Such personalized trials have the potential to yield better outcomes by increasing the probability of response and to employ less toxic therapies by increasingly targeting cancer-specific functions, rather than normal proliferative functions.
To the extent that targeted therapies will prove more effective when given to selected patients, clinical trials should get dramatically smaller. Trial size is largely driven by how effective the treatment is expected to be, so fewer participants are needed when the therapeutic benefit is larger. But the promise of smaller trials will not to be universal; for example, when two targeted agents are compared to one another in the same molecularly selected population, the differences in efficacy may be small and larger trials will be required.
As approaches to cancer treatment advance, there will need to be continual engagement with patients and with cancer survivors.
Furthermore, smaller trials may not necessarily move faster or be easier to complete, as they will require the “right patients,” who may be hard to find. Many of the mutations that represent promising targets are present in a minority of tumors. Today, molecular characterization of tumors is often done as part of the screening process for each trial. Many, and sometimes most, of the patients prove ineligible, making this approach frustrating and difficult to carry out. A better avenue of attack would be to make comprehensive molecular characterization of tumors a routine part of establishing a patient’s eligibility for a range of therapies. With the plummeting cost of genomic analysis, one can envision a day in the near future when a complete cancer genome (and perhaps other molecular evaluations) becomes a standard component of an initial diagnostic evaluation. Patients will be armed with molecular information about their own tumors, and thus able to make more-informed decisions about standard and investigational therapies that match the mutations driving their cancer.

New challenges

The road to personalized and targeted treatment strategies will offer new challenges. For rare targets that are present in a minority of cases across many different types of cancers, one will have to consider clinical trials that include a number of different cancers. There are many design pitfalls to such trials, chiefly the additional clinical and molecular heterogeneity introduced by the inclusion of more than one cancer type. Despite these challenges, it will inevitably make sense in some settings to select patients who share a particular tumor biology, regardless of the tissue of origin.
Another major challenge is how to combine targeted therapies to improve clinical outcomes. To date, targeted therapies have not been able to cure advanced solid tumors. Clinical benefits, while sometimes quite impressive when compared to marginally effective treatments, still fall far short. It stands to reason that redundant survival and growth pathways enable tumors to overcome therapies that inhibit a single target. The simultaneous inhibition of relevant redundant pathways may yield dramatically better results, but will also dramatically increase the complexity of molecularly personalized clinical trials.
As approaches to cancer treatment advance, there will need to be continual engagement with patients and with cancer survivors. Fewer than 5 percent of adult cancer patients participate in a clinical trial. To carry out meaningful clinical trials in the future, that number must increase. This will be most important for treatments that target relatively rare mutations; a large number of potential volunteers will have to be screened to identify a sufficient number who harbor the relevant target. To succeed, we must partner with a much larger fraction of cancer patients.
Designing and executing future cancer clinical trials will not be easy, but physician-scientists are armed with a fast-growing body of omics-informed knowledge with which to surmount these hurdles.
Tomasz M. Beer is deputy director of the Knight Cancer Institute and a professor of medicine at Oregon Health & Science University in Portland. He is the coauthor of Cancer Clinical Trials: A Commonsense Guide to Experimental Cancer Therapies and Clinical Trials. Written for people living with cancer, the book is accompanied by a blog (www.cancer-clinical-trials.com) that seeks to disseminate knowledge about clinical trials.

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tumor suppression, tumor heterogeneity, genetics & genomics, disease/medicine, clinical trials, chemotherapy, cancer genomics and cancer

UPDATED 4/23/2020:  New Design for Phase 1 pediatric oncology trials to expedite dose escalation studies.

 

REVIEW

Ushering in the next generation of precision trials for pediatric cancer

Steven G. DuBois, Laura B. Corson, Kimberly Stegmaier, Katherine A. Janeway

Science  15 Mar 2019:Vol. 363, Issue 6432, pp. 1175-1181 DOI: 10.1126/science.aaw4153

 

Abstract

Cancer treatment decisions are increasingly based on the genomic profile of the patient’s tumor, a strategy called “precision oncology.” Over the past few years, a growing number of clinical trials and case reports have provided evidence that precision oncology is an effective approach for at least some children with cancer. Here, we review key factors influencing pediatric drug development in the era of precision oncology. We describe an emerging regulatory framework that is accelerating the pace of clinical trials in children as well as design challenges that are specific to trials that involve young cancer patients. Last, we discuss new drug development approaches for pediatric cancers whose growth relies on proteins that are difficult to target therapeutically, such as transcription factors.

Some terms from the bibliography:

3+3 design: A commonly used rule-based design for phase 1 clinical trials in which patients are enrolled in cohorts of three patients, and decisions to increase or decrease the dose level for the next three participants are based on toxicities observed in those three patients.

 

Basket trial: A precision oncology trial design in which patients with many different cancer types are enrolled, the tumor is tested for a set of biomarkers of interest, and then patients are assigned to one of several clinical trial subprotocols based on the presence of a biomarker corresponding to a particular molecularly targeted therapy.

 

Bayesian model–based trial designs: A broad class of trial designs that use data known before the trial as well as data obtained during the conduct of the trial to adapt trial parameters as more information becomes available

Continual reassessment method: One example of a Bayesian model–based trial design in which an initial mathematical model of the relationship between drug dose and probability of unacceptable toxicity is continually updated as new information becomes available to assign subsequent patients to a dose anticipated to have an unacceptable toxicity rate below a set rate.

First-in-child trial: The first clinical trial of a specific agent to include a pediatric population, traditionally considered patients <18 years of age.

 

Rolling 6 design: A variation of the 3+3 design in which up to six participants may be enrolled to a dosing cohort before enrollment pauses to assess toxicity.

Safety run-in: An initial component of a phase 2 or phase 3 trial in which a small group of patients are treated with a previously untested regimen to evaluate toxicity before opening the trial to a larger group of participants.

Umbrella trial: A precision oncology trial design in which patients with a specific cancer type are enrolled, tumor is tested for a set of biomarkers of interest, and then patients are assigned to one of several clinical trial subprotocols based on the presence of a biomarker corresponding to a particular molecularly targeted therapy.

 

In this review article, DuBois et al describe new paradigms for pediatric precision oncology trial design and how these designs should be contrasted with the old models and differentiate from the design for these types of trials in the adult.  As the genomic landscape of pediatric tumors is becoming clearer (1, 2) the authors noticed two themes which are becoming evident:

  1. Pediatric cancers harbor certain genomic mutations rarely seen in adult cancers
  2. Pediatric cancers share some genomic alterations and mutational gene signatures with adult tumors

However there is only a small number of pediatric clinical trials to investigate if specific genetic mutations predict outcome to a given personalized therapy.

            Thus, there an urgent need for precision clinical trials in pediatric cancers.

Several reviews have described numerous ongoing and recently completed trials however most are phase 1 dose escalation trials including basket trials and umbrella trials but based on previous data from adult trials using the same precision drug.  For example, pediatric trials involving the TRK inhibitor laratrectinib in tumors harboring a NTRK fusion gene or a pediatric crizotinib trial for pediatric glioblastomas having an ALK fusion protein have shown great success yet most of the early phase 1 work was based on adults or carried out in a way that does not take advantage of the new regulatory framework designed to expedite new drugs for adult precision medicines.

Speeding up the early phase trials in pediatric cancers: new trial design paradigms

Dose escalation phase I trials have, traditionally been the starting point for clinical development of new pediatric anticancer drugs however these first in child trials have seriously lagged their adult counterparts by many years.  These trials relied on the standard 3 x 3  or rolling six trial design, and doses escalated until a pediatric MTD  (maximum tolerated dose) was achieved.  In recent years new precision medicine pediatric trial design has been adopted to expedite the process, based on the fundamental shift in thinking that many new oncology agents will not have a true MTD when tested in adults.

Doses in phase 1 trials for targeted therapies like those in precision medicine are usually escalated based on considerations other than toxicity, like pharmacodynamics or biomarker analysis.  A pediatric phase 1 dose escalation trial may require more subjects than an adult trial.  But

although these newer approaches to early-phase trial design more efficiently establish a pediatric dose, they do little to advance our understanding of with patients are most likely to benefit from a new therapy.

Thus the need for good biomarkers to be included early on in these initial trial designs.  For example, Dana Farber’s first in child clinical trial NCT03654716, a Phase 1 Study of the Dual MDM2/MDMX Inhibitor ALRN-6924 in Pediatric Cancer (as a possible treatment for resistant (refractory) solid tumor, brain tumor, lymphoma or leukemia), are reducing the time children are waiting for entry into a trial, as unselected patients can enroll and the biomarker, increased MDM2 expression is used to determine those patients who go on to phase 2 dose escalation. In other cases, such as NCI Children’s Oncology Group basket trials, they have completely supplanted formal phase 1 trial design and instead incorporated molecularly targeted therapies based on adult doses but adjusted for patient size.  The use of combinations with traditional therapies in trial design is also helping to speed up the process for enrollment.  The authors also suggest that tumor profiling is pertinent however should be put in trial design so the costs to patients can be covered by the trial funds.

 

Figure 1Fig. 1 Evolution of precision trials for pediatric cancer.

Illustration: Kellie Holoski/Science

Source: Ushering in the next generation of precision trials for pediatric cancer BY STEVEN G. DUBOIS, LAURA B. CORSON, KIMBERLY STEGMAIER, KATHERINE A. JANEWAY SCIENCE 15 MAR 2019 : 1175-1181 https://science.sciencemag.org/content/363/6432/1175

 

  1. S. N. Gröbner, B. C. Worst, J. Weischenfeldt, I. Buchhalter, K. Kleinheinz, V. A. Rudneva, P. D. Johann, G. P. Balasubramanian, M. Segura-Wang, S. Brabetz, S. Bender, B. Hutter, D. Sturm, E. Pfaff, D. Hübschmann, G. Zipprich, M. Heinold, J. Eils, C. Lawerenz, S. Erkek, S. Lambo, S. Waszak, C. Blattmann, A. Borkhardt, M. Kuhlen, A. Eggert, S. Fulda, M. Gessler, J. Wegert, R. Kappler, D. Baumhoer, S. Burdach, R. Kirschner-Schwabe, U. Kontny, A. E. Kulozik, D. Lohmann, S. Hettmer, C. Eckert, S. Bielack, M. Nathrath, C. Niemeyer, G. H. Richter, J. Schulte, R. Siebert, F. Westermann, J. J. Molenaar, G. Vassal, H. Witt, B. Burkhardt, C. P. Kratz, O. Witt, C. M. van Tilburg, C. M. Kramm, G. Fleischhack, U. Dirksen, S. Rutkowski, M. Frühwald, K. von Hoff, S. Wolf, T. Klingebiel, E. Koscielniak, P. Landgraf, J. Koster, A. C. Resnick, J. Zhang, Y. Liu, X. Zhou, A. J. Waanders, D. A. Zwijnenburg, P. Raman, B. Brors, U. D. Weber, P. A. Northcott, K. W. Pajtler, M. Kool, R. M. Piro, J. O. Korbel, M. Schlesner, R. Eils, D. T. W. Jones, P. Lichter, L. Chavez, M. Zapatka, S. M. Pfister, ICGC PedBrain-Seq Project, ICGC MMML-Seq Project, The landscape of genomic alterations across childhood cancers. Nature 555, 321–327 (2018). 10.1038/nature25480pmid:29489754

 

2.  X. Ma, Y. Liu, Y. Liu, L. B. Alexandrov, M. N. Edmonson, C. Gawad, X. Zhou, Y. Li, M. C. Rusch, J. Easton, R. Huether, V. Gonzalez-Pena, M. R. Wilkinson, L. C. Hermida, S. Davis, E. Sioson, S. Pounds, X. Cao, R. E. Ries, Z. Wang, X. Chen, L. Dong, S. J. Diskin, M. A. Smith, J. M. Guidry Auvil, P. S. Meltzer, C. C. Lau, E. J. Perlman, J. M. Maris, S. Meshinchi, S. P. Hunger, D. S. Gerhard, J. Zhang, Pan-cancer genome and transcriptome analyses of 1,699 paediatric leukaemias and solid tumours. Nature 555, 371–376 (2018). 10.1038/nature25795pmid:29489755

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