AML-262 Pivekimab Sunirine (PVEK, IMGN632) Triplet With Azacitidine and Venetoclax Shows Broad Activity in Adverse Genetic Subsets of Relapsed/Refractory Acute Myeloid Leukemia and Reduced Infusion-Related Reactions
Daver N., Montesinos P., Aribi A., Martinelli G., Altman JK., Wang ES., Roboz GJ., Burke PW., Gaidano G., Walter RB., Thomas X., Jeyakumar D., DeAngelo DJ., Erba HP., Todisco E., Begna K., Advani A., Gastaud L., de la Fuente A., Curti A., Mendez LM., Vyas P., Boissel N., Vey N., Recher C., Longval T., Platzbecker U., Kapp-Schwörer S., Schliemann C., Konopleva M., Torres L., Sallman DA., Marcucci G., Marconi G., Kantarjian H., Sloss CM., Malcolm KE., Zweidler-McKay PA., Sweet K.
Context: Pivekimab sunirine (PVEK, IMGN632) is a first-in-class ADC comprising a CD123 high-affinity antibody, a cleavable linker, and an IGN (indolinobenzodiazepine pseudodimer) payload. PVEK with azacitidine (AZA) and venetoclax (VEN) is a novel triplet that has demonstrated anti-leukemia activity in relapsed/refractory AML patients. Objective: Evaluate the anti-leukemia activity in genetic subgroups of AML and safety of the triplet. Intervention: Patients with relapsed/refractory AML received PVEK+AZA+VEN in a three-drug escalation over a 28-day cycle: PVEK 0.015 or 0.045 mg/kg day 7, AZA 50 or 75 mg/m2 days 1–7, and VEN 400 mg for 8, 14, or 21 days. Results: Twenty-nine patients (median age 67 y, ELN adverse 62%, prior VEN 48%) were in higher-intensity cohorts (PVEK 0.045 mg/kg and/or VEN for 14 or 21 days). The overall response rate (ORR) was 59% (4 CR, 6 CRh, 1 CRp, 6 MLFS) and the composite complete remission rate (CCR, CR+CRh+CRp+CRi) was 38%. Higher rates are seen in patients with FLT3-ITD (n=9, ORR 89%, CCR 78%), IDH2 (n=4, ORR 75%, CCR 75%), and WT1 (n=7, ORR 57%, CCR 43%) mutations. Lower rates are seen in patients with monosomy 7/abn7q (n=6, ORR 17%, CCR 17%), TP53 (n=4, ORR 25%, CCR 25%), and ASXL1 (n=6, ORR 67%, CCR 17%) deletions or mutations. The safety profile for the PVEK triplet is similar to AZA+VEN. No VOD, TLS, or CRS was reported. IRRs were reported in 33% (n=17, one grade 4) of patients given 1 dose of dexamethasone (8 mg) as premedication (n=51); these IRRs were most frequently tachycardia and chills, with no anaphylactic reactions reported. Following the data cut-off, there was a second grade 4 IRR, and the prophylactic regimen was increased with two additional doses of dexamethasone on the day prior to the PVEK dose. The IRR rate has dropped to 8% (3 of 38), with no grade 3+; all were grades 1–2 that resolved with limited intervention (P<0.01). Conclusions: The PVEK triplet with AZA+VEN demonstrates anti-leukemic activity across multiple high-risk genetic subsets of relapsed/refractory AML. Prophylactic steroids added on day –1 have significantly reduced IRRs. Expansion cohorts are now enrolling for untreated and relapsed AML patients (NCT04086264).