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Transcript of JEFFREY LONGMATE, PHD - MECCmeccinc.com › wp-content › uploads › 2018 › 09 ›...
14th Annual California Cancer Conference Consortium
August 10-12, 2018
JEFFREY LONGMATE, PHD CLINICAL TRIALS 101: PHASE I EXPANSION COHORTS VS
PHASE II TRIALS
NO RELEVANT FINANCIAL RELATIONSHIPS IN THE PAST TWELVE MONTHS BY PRESENTER OR SPOUSE/PARTNER.
THE SPEAKER WILL DIRECTLY DISCLOSE THE USE OF PRODUCTS WHICH ARE NOT LABELED (E.G., OFF LABEL USE)
OR IF THE PRODUCT IS STILL INVESTIGATIONAL.
FURTHER NOTICE:
• This is a talk about clinical trial design, and not about the
conclusions to be drawn from specific trials.
• Any mention of clinical trial outcomes is intended to illustrate
features of the trial designs, and is not intended to inform
medical practice.
“
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Recently, sample sizes of expansion cohorts in FIH trials have
surpassed 100 patients, with total sample sizes of individual
‘phase I’ trials exceeding 1,000 patients in a limited number of
cases.
Use of trial nomenclature that categorizes a 1,000 patient protocol
as a phase I trial fails to capture the complexity of the evolving
objectives of these large expansion cohort trials. This is not a
simple matter of semantics, ...
Theoret et al. 2015 Clinical Cancer Research
THE AIMS OF PHASE I TRIALS ARE BEING EXPANDED, BUT NOT ALWAYS
EXPLICITLY.
MAJOR POINTS
• Use of expansion cohorts in increasing.
• Phase II success is associated with moderate Phase I
expansions
• MTD is not well established by ordinary Phase I
• There are many reasons for expansions in Phase I
• Expansion cohorts may be part of the drug development
pathway — with caveats.
• 522 adult therapeutic phase I trials were identified during the
25 years from 1988 to 2012.
• The average sample size of a phase I study has increased from
33.8 patients to 73.1
• Sixteen of the 60 trials (27%) in 2011 enrolled patients to three
or more sub-cohorts in the expansion phase.
Evaluation of Statistical Designs in Phase I Expansion Cohorts:
The Dana-Farber/Harvard Cancer Center Experience Suzanne E. Dahlberg, Geoffrey I. Shapiro, Jeffrey W. Clark, Bruce E. Johnson
JNCI J Natl Cancer Inst (2014)
The primary intention of the expansion cohort has
evolved into an opportunity to garner efficacy data …
Trials with large expansion cohorts do not always
provide statistical justification for their sample sizes,
even though the total number of patients to be enrolled
may approximate or even exceed the number of patients
required for evaluation of the agent in a stand-alone
phase II trial testing a specified hypothesis.
— Dahlberg et al. 2014 JNCI
Evolution of Clinical Trial Design in Early Drug Development: Systematic
Review of Expansion Cohort Use in Single-Agent Phase I Cancer Trials Arif Manji, Irene Brana, Eitan Amir, George Tomlinson, Ian F. Tannock, Philippe L. Bedard,
Amit Oza, Lillian L. Siu, and Albiruni R. Abdul Razak
2013 JOURNAL OF CLINICAL ONCOLOGY
• Identified 611 unique phase I cancer trials, 149 (24%) included an expansion cohort.
• The trials more likely to use an expansion cohort were published more recently,
were multicenter, or evaluated a noncytotoxic agent.
• 26% fail to report explicit aims. Those that did cited:
• safety (80%),
• efficacy (45%),
• pharmacokinetics (28%),
• pharmacodynamics (23%),
• patient enrichment (14%).
• Among trials aimed at assessing efficacy, only 11% demonstrated antitumor activity
not previously observed during dose escalation.
• Identified 533 phase I trials evaluating 381 drugs; 112 drugs had at
least one phase I trial with an expansion cohort.
• Phase I trials with expansion cohorts of two to 20 patients were
associated with a higher rate of successful phase II trials than those
with no expansion cohort [48% vs. 27%].
• Phase II success rates were similar (48% vs. 52%) for expansion
cohorts with two to 20 and more than 20 patients.
• Drugs tested in phase I trials with expansion cohorts had a higher
rate of 5-year approval (19% vs. 5%).
Use of Expansion Cohorts in Phase I Trials and Probability of Success in
Phase II for 381Anticancer Drugs Diogo D.G. Bugano, Kenneth Hess, Denis L.F. Jardim, Alona Zer, Funda Meric-Bernstam, Lillian L. Siu,
Albiruni R.A. Razak, and David S. Hong Clin Cancer Res; 23(15) August 1, 2017
Conclusion : The better agents may be more
likely to be evaluated with expansion cohorts, or
the expansion cohorts may help with successful
progress.
Approaches to expansion-based dose adjustment:
1. Using Safety Data Alone—Retrospective Assessment
2. Prospectively Guiding Dose Expansion Using Safety
3. Prospectively Guiding Dose Expansion Using Safety and
Efficacy
4. Experimenting at More Than a Single Level
5. Taking Into Account Different Eligibility Criteria
Design Considerations for Dose-Expansion Cohorts in Phase I Trials Alexia Iasonos and John O’Quigley
2013 JOURNAL OF CLINICAL ONCOLOGY
Simulation of approach 1: 3+3 escalation, followed by
expansion, with final revision of MTD.
• The assumption that we have reached the MTD during the dose-
escalation phase and that thus patients in the expansion cohort are
receiving the right dose is not always true.
• We argue that DECs in phase I studies need to be sequentially
monitored for safety, and experimentation should be adaptively
changed if supported by the results.
• How many patients are needed depends on
A. the objective of the study,
B. the number of levels in the dose-escalation
C. whether multiple drugs, schedules, or disease groups are
involved.
D. the amount of information borrowed between groups.
• We suggest that the DEC size should be at least 50% of the pre-
expansion sample size, or a minimum of 12 to 15 patients, to obtain
some meaningful preliminary evidence for efficacy.
Involves:
1. Dose escalation by mTPI
2. Dose graduation rule based on both toxicity and efficacy.
3. Adaptive randomization in phase II
A phase I/II seamless dose escalation/expansion with adaptive
randomization scheme (SEARS) Haitao Pan, Fang Xie, Ping Liu, Jielai Xia and Yuan Ji Clinical Trials 2014
Anti-programmed-death-receptor-1 treatment with pembrolizumab in
ipilimumab-refractory advanced melanoma: a randomised dose-comparison
cohort of a phase 1 trial Caroline Robert, et al.
www.thelancet.com Vol 384 September 20, 2014
ORR was 26% at both doses
Nivolumab for Metastatic Renal Cell Carcinoma: Results of a Randomized Phase II Trial Robert J. Motzer, et al. JOURNAL OF CLINICAL ONCOLOGY, 2015
CONCLUSION
Nivolumab demonstrated antitumor
activity with a manageable safety
profile across the three doses
studied in mRCC. No dose-
response relationship was detected
as measured by PFS.
Expansion Cohorts in First-in-Human Solid Tumor Oncology Trials Marc R. Theoret, Lee H. Pai-Scherf, Meredith K. Chuk, Tatiana M. Prowell, Sanjeeve Balasubramaniam, Tamy Kim,
Geoffrey Kim, Paul G. Kluetz, Patricia Keegan, and Richard Pazdur Clin Cancer Res; 21(20) October 15, 2015
Marketing approval has traditionally relied upon sequential trials
(e.g., phase I, phase II, and phase III). At a high level, there are
often multiple objectives within each phase.
FIH expansion cohorts objectives may be separate from the initial
dose-escalation portion, and may include:
• additional PK and PD endpoints,
• alternative dosage regimens,
• toxicity characterization,
• product formulation development,
• evaluation for predictive biomarkers,
• and increasingly, preliminary assessment of antitumor
activity.
The initial drug development program of pembrolizumab is a well-known example of a
breakthrough therapy–designated immunotherapeutic product evaluated in an FIH trial that
utilized multiple expansion cohorts to fulfill various drug development objectives.
CONCLUSIONS FROM DAHLBERG ET AL.
• phase I studies have changed in size and scientific scope over the last
25 years.
• We recommend that phase I studies justify their planned sample sizes
• The appropriate stakeholders should set expectations for justifications
of proposed sample sizes and designs and consider an appropriate
designation that goes beyond the designation of phase I.
• reports of phase I studies include designs and results for all expansion
cohorts of a particular study.
• Further studies of this trend’s impact on research processes, ethical
implications, and resource burden are needed.
THIS MORNING: FDA GUIDANCE (DRAFT)
Principal advantage:
• Making highly effective drugs available quickly
Challenges:
• disseminating safety information
• exposing many patients to sub-optimal or toxic
doses
• exposing more patients than required for cohort
objectives
• possibly missed interpretation of preliminary
results
FIH multiple expansion cohorts should be limited to
drugs for indications and patient populations in which
the potential benefits justify the increased risks.
Thank you