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Endpoints for Past Approvals. Ramzi Dagher DODP/CDER/FDA. Endpoints in Oncology. Survival (gold standard) TTP (advantages and challenges) DFS (adjuvant setting) ORR (treatment responsible for tumor reduction) Tumor related symptoms/PRO. Clinical Benefit Endpoints : Regular Approval.
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Endpoints for Past Approvals Ramzi Dagher DODP/CDER/FDA
Endpoints in Oncology • Survival (gold standard) • TTP (advantages and challenges) • DFS (adjuvant setting) • ORR (treatment responsible for tumor reduction) • Tumor related symptoms/PRO
Clinical Benefit Endpoints : Regular Approval • Survival • Improvement in tumor related symptoms • DFS (adjuvant setting, breast cancer)
Surrogates Used forRegular Approval • Durable Complete Response • leukemias • some solid tumors • Partial Response • hormonal therapy of breast cancer
DODP : Endpoints for Approval1/1/90 - 11/1/02 Approvals not based on survival: • 73% (48/66) of all approvals • 67% (37/55) excluding AA
Tumor Related Symptoms • Mitoxantrone for HRPC • pain scale • Photofrin for obstructive lesions • dysphagia scale • Bisphosphonates • skeletal related events
Trial Designs and Surrogate Endpoints for AA • Single-arm trials or comparison of two dose levels • 15 out of 22 AA indications • objective response rate (e.g. imatinib, gefitinib) • Randomized trials : placebo or active comparator • DFS (anastrozole) • RR/TTP (oxaliplatin)
AA and Confirmatory Study Design Strategy 1: • AA based on RR as the endpoint in single arm studies of refractory patients • subsequent confirmatory studies in less refractory patients • Pro: • rapid completion of single arm studies expedites drug availability
AA and Confirmatory Study Design : Strategy 1 (cont’d) • Cons: • AA may influence the ability to enroll patients to confirmatory studies • challenge of evaluating marginal benefits • may miss an active drug • limitations of single arm trials • endpoints • toxicity evaluation
AA and Confirmatory Study Design Strategy 2: • AA based on interim analysis of a surrogate endpoint in a randomized study • Clinical benefit established by final analysis of the same study • Pros: • same population for AA and regular approval • facilitates completion of confirmatory study • randomized setting allows comparison to available therapy and evaluation of toxicity profile
AA and Confirmatory Study Design Strategy 2 (continued): • Cons: • May require more time and patients than single arm study • AA could influence completion of study
Summary • Survival, tumor symptom improvement as evidence of CB • Surrogates for CB • CR’s in leukemia • PR’s in hormonal breast cancer therapy • ORR in single-arm trials basis of approval in most AA’s