A combination cohort in a phase 1 study (NCT01902329) assessed safety, tolerability, and activity of vadastuximab talirine with HMAs....Eligible patients had a new diagnosis of CD33-expressing AML, as determined by local laboratory assessment by flow cytometry....Thirty- and 60-day mortality rates were 2% and 8%, respectively. The composite remission rate (complete remission [CR] and CR with incomplete blood count recovery) was 70%. Fifty-one percent of remissions were minimal residual disease-negative by flow cytometry. Similarly high remission rates were observed in patients with secondary AML, aged at least 75 years, and with adverse cytogenetic risk. Median relapse-free survival and overall survival were 7.7 and 11.3 months, respectively.

The dose-escalation portion of this phase 1 study (#NCT01902329) was designed to evaluate the safety, tolerability, pharmacokinetics (PK), and antileukemic activity of vadastuximab talirine as monotherapy, with the primary objectives of determining the safety, tolerability, and MTD of vadastuximab talirine in patients with CD33-expressing AML....The 30-day mortality was 8%. At the recommended monotherapy dose of 40 µg/kg, the complete remission + CRi rate was 28% (5 of 18 patients); 50% of patients who responded achieved minimal residual disease negativity. In patients across dose levels who achieved CR or CRi...