Design and analysis of trials of salvage therapy in acute myelogenous leukemia.
Results obtained with a given regimen in relapsed or refractory acute myelogenous leukemia (AML) are variable. This often reflects variability in patient selection. We have developed a system to account for such variability that stratifies patients with refractory or relapsed AML into four groups: group 1, first complete response (CR) duration > or = 2 years and receiving first salvage treatment (S1); group 2, first CR duration 1-2 years and receiving S1; group 3, first CR duration 0-1 years and receiving S1; and group 4, first CR duration 0-1 years and receiving S2, S3, or S4 after failing S1. CR rates achieved in the four groups are 73%, 47%, 14%, and 0, respectively. This system is useful for comparing results obtained with different therapies and for assigning patients to treatment. At our institution, patients in group 4 are enrolled in phase I studies, and phase I1/2-II studies are carried out separately in patients in groups 2, 3, and 4. A phase I1/2 study refers to one in which the intent is to select for phase II therapies emerging from phase I trial results. The design is Bayesian, and although false-negative rates are relatively high, they are lower than those obtained if a drug for phase II testing is arbitrarily selected.
Estey
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University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Thall
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David
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D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001499:Bayes Theorem; D017322:Clinical Trials, Phase II as Topic; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy*; D015588:Observer Variation; D015203:Reproducibility of Results; D012107:Research Design; D016879:Salvage Therapy; D016896:Treatment Outcome
D000970:Antineoplastic Agents