Complete Remission with Partial Hematological Recovery as a Palliative Endpoint for Treatment of Acute Myeloid Leukemia

Complete remission with partial hematological recovery (CRh) has been used as an efficacy endpoint in clinical trials of nonmyelosuppressive drugs for acute myeloid leukemia (AML). We conducted a pooled analysis to characterize the clinical outcomes for patients with AML who achieved CRh after treatment with ivosidenib, olutasidenib, enasidenib, or gilteritinib monotherapy in clinical trials used to support marketing applications. The study cohort included 841 adult patients treated at the recommended drug dosage; 64.6% were red blood cell or platelet transfusion dependent at study baseline. Correlations between disease response and outcomes were assessed by logistic regression modeling for categorical variables and by Cox proportional hazards modeling for time-to-event variables. In comparison to patients with no response (NR), those with CRh had a higher proportion with transfusion independence (TI) for at least 56 days (92.3% vs 22.3%, p < 0.0001) or TI for at least 112 days (63.5% vs 8.7%, p < 0.0001), a reduced risk over time for severe infection (HR 0.43, p = 0.0007) or severe bleeding (HR 0.17, p = 0.01), and a longer overall survival (OS) (HR 0.31, p < 0.0001). The effects were consistent across drugs. In comparison to patients with CR, the effect sizes for CRh were similar for TI-56 and for risk over time of infection or bleeding but less for TI-112 and OS. CRh is associated with clinical benefits consistent with clinically meaningful palliative effects for treatment of AML with nonmyelosuppressive drugs, although less robustly than for CR.