CC-486 (oral azacitidine) in patients with myelodysplastic syndromes with pretreatment thrombocytopenia.

Thrombocytopenia is among the strongest predictors of decreased survival for patients with myelodysplastic syndromes (MDS) across all prognostic risk groups. The safety and efficacy of CC-486 (oral azacitidine) was investigated in early-phase studies; we assessed clinical outcomes among subgroups of MDS patients from these studies, defined by presence or lack of pretreatment thrombocytopenia (≤75 × 109/L platelet count). Patients received CC-486 300 mg once-daily for 14 or 21 days of repeated 28-day cycles. Overall, 81 patients with MDS, median age 72 years, comprised the Low Platelets (n = 45) and High Platelets (n = 36) cohorts. Pretreatment median platelet counts were 34 × 109/L and 198 × 109/L, respectively. Grade 3-4 bleeding events occurred in 2 patients in the Low Platelets and 1 patient in the High Platelets groups; events resolved without sequelae. Treatment-related mortality was reported for 7 patients, 5 of whom had pretreatment platelet values <25 × 109/L. Overall response rates were 38% and 46% in the Low Platelets and High Platelets groups, respectively. Five thrombocytopenic patients attained complete remission and 9 attained platelet hematologic improvement. In both cohorts, platelet counts dropped during the first CC-486 treatment cycle, then increased thereafter. Extended CC-486 dosing was generally well tolerated and induced hematologic responses in these patients regardless of pretreatment thrombocytopenia.

Extended dosing with CC-486 (oral azacitidine) in patients with myeloid malignancies.

CC-486 (oral azacitidine) is an epigenetic modifier in clinical development for treatment of hematological cancers. This study of extended CC-486 dosing included patients with myelodysplastic syndromes (MDSs), chronic myelomonocytic leukemia (CMML), or acute myeloid leukemia (AML). After a pharmacokinetic assessment period, 31 patients (MDS n = 18, CMML n = 4, and AML n = 9) entered a clinical phase in which they received CC-486 300 mg once-daily for 21 days of repeated 28-day cycles. Median age was 71 years (range: 53-93); 42% of patients were aged ≥75 years. A total of 5 patients with AML (63%) had prior MDS. Median number of CC-486 treatment cycles was 4 (range: 1-32). The most common treatment-emergent adverse events (TEAEs) were gastrointestinal (84% of patients) and hematologic (81%). Most common grade 3-4 TEAEs were neutropenia (n = 13, 42%) and anemia (n = 9, 29%). Ten patients experienced grade 4 neutropenia. Infrequently, CC-486 dose was interrupted or reduced due to gastrointestinal (n = 5, 16%) or hematologic (n = 6, 19%) TEAEs. Overall response rate (complete remission [CR], CR with incomplete hematological recovery [CRi], partial remission [PR], marrow CR) in the MDS/CMML subgroups was 32% and in the AML subgroup (CR/CRi/PR) was 22%. Red blood cell transfusion independence rates in the MDS/CMML and AML subgroups were 33% and 25%, respectively, and 2 MDS/CMML patients attained hematologic improvement as a best response on-study. No baseline gene mutation was predictive of response/nonresponse. CC-486 allows flexible dosing and schedules to improve tolerability or response. Neutropenia in early treatment cycles deserves scrutiny and may warrant initiation of prophylactic antibiotics. KEY POINTS: The safety profile of oral CC-486 was comparable to that of injectable azacitidine; most adverse events were hematological and gastrointestinal. Extended (21-day/cycle) CC-486 dosing induced responses in patients with hematological malignancies, many of whom had prior DNMTi failure.