Phase II study of pevonedistat (P) + azacitidine (A) versus A in patients (pts) with higher-risk myelodysplastic syndromes (MDS)/chronic myelomonocytic leukemia (CMML), or low-blast acute myelogenous leukemia (LB AML) (NCT02610777).
Lionel Adès, Justin M. Watts, Atanas Radinoff, Montserrat Arnán, Marco Cerrano, Patricia Font, Joshua F. Zeidner, María Díez‐Campelo, Carlos Graux, Jane L. Liesveld, Dominik Selleslag, Nikolay Tzvetkov, Robert J. Fram, Dan Zhao, Douglas V. Faller, Mikkael A. Sekeres
Abstract
7506 Background: P, the first and only small-molecule inhibitor of the NEDD8-activating enzyme, disrupts proteasomal degradation of select proteins and has shown promising clinical activity and good tolerability in combination with A in AML. Methods: 120 pts with higher-risk (Revised International Prognostic Scoring System risk > 3) MDS/CMML or LB AML naïve to hypomethylating agents were randomized 1:1 to receive P 20 mg/m 2 intravenously (IV) on days (d) 1, 3, 5 + A 75 mg/m 2 (IV/subcutaneously) on d 1–5, 8, 9 (n = 58), or A alone (n = 62), in 28-d cycles until unacceptable toxicity, relapse, transformation to AML, or progression. The primary endpoint was overall survival (OS), although the study was underpowered for OS. Results: Baseline characteristics were generally balanced between arms. Pts received a median of 13.0 vs 8.5 cycles of P+A vs A. Median OS in the intent-to-treat (ITT) population with P+A vs A (n = 120) was 21.8 vs 19.0 mos (hazard ratio [HR] 0.80; 95% CI 0.51–1.26; P = .334; median follow-up 21.4 vs 19.0 mos). Subanalyses showed median OS with P+A vs A in higher-risk MDS (n = 67) of 23.9 vs 19.1 mos (HR 0.70; 95% CI 0.39–1.27; P = .240) and in LB AML (n = 36) of 23.6 vs 16.0 mos; HR 0.49; 95% CI 0.22–1.11; P = .081). Event-free survival (EFS – time from randomization to death/transformation to AML) with P+A vs A trended longer in the ITT population (median 21.0 vs 16.6 mos; HR 0.65; 95% CI 0.41–1.02; P = .060) and was significantly longer in higher-risk MDS (median 20.2 vs 14.8 mos; HR 0.54; 95% CI 0.29–1.00; P = .045). In response-evaluable pts, overall response rate was 71% (n = 39/55; 46% complete remission [CR] + CR with incomplete blood count recovery [CRi], 5% partial response [PR], 20% hematologic improvement [HI]) with P+A vs 60% (n = 32/53; 38% CR+CRi, 8% PR, 15% HI) with A. In higher-risk MDS, CR rate was 52% vs 27% ( P = .050) with P+A vs A. Median A dose intensity was 97% vs 98% with P+A vs A. Rates of grade ≥3 adverse events were 90% vs 87% with P+A vs A; the most common were 31% vs 27% neutropenia, 26% vs 29% febrile neutropenia, 19% vs 27% anemia, and 19% vs 23% thrombocytopenia. On-study deaths occurred in 9% of P+A pts and 16% of A pts. Conclusions: P+A had a comparable safety profile to A alone, did not increase myelosuppression, and maintained A dose intensity. Although not statistically significant, P+A increased OS, EFS, and response rates vs A, particularly in pts with higher-risk MDS. Further evaluation of P+A vs A is ongoing in a randomized phase. Clinical trial information: NCT02610777 .