Leukemia-free survival as a surrogate end point for overall survival in the evaluation of maintenance therapy for patients with acute myeloid leukemia in complete remission

• BACKGROUND: In trials designed to evaluate new therapies for hematologic malignancies, end points such as leukemia-free survival are often used as surrogates for overall survival in acute leukemia. We aimed to assess whether leukemia-free survival is an acceptable statistical surrogate for overall survival when applied to remission maintenance therapy for acute myeloid leukemia. DESIGN AND METHODS: Data were analyzed from a randomized Phase III trial of remission maintenance immunotherapy with histamine dihydrochloride plus low-dose interleukin-2 versus no treatment in adults with acute myeloid leukemia. A two-stage surrogate validation model was applied in which correlations between Kaplan-Meier estimates of leukemia-free survival and overall survival, and between log hazard ratios reflecting treatment effects were analyzed. Country of patient enrollment was the unit of analysis. RESULTS: Kaplan-Meier estimates of overall survival at 36, 48, and 60 months and leukemia-free survival at 24 months were reasonably correlated (R(2) ranging from 0.44 to 0.84) both for the overall (n=320) and first complete remission (n=261) populations. The effects of histamine dihydrochloride/interleukin-2 on log hazard ratios for leukemia-free survival and overall survival were well correlated (R(2)=0.88-0.93). CONCLUSIONS: The significant correlations between overall survival and the surrogate end point (leukemia-free survival) and between the effect of histamine dihydrochloride/interleukin-2 on leukemia-free survival and overall survival satisfy the two-stage surrogate validation model.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Immunologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Immunology in the medical area (hsv//eng)

Nyckelord

leukemia-free survival

overall survival

immunotherapy

statistical analyses

clinical trial interpretation

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ref (ämneskategori)

art (ämneskategori)