Safety, tolerability, and pharmacokinetics of ASP1235 in relapsed or refractory acute myeloid leukemia: A phase 1 study

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy. Although new agents including targeted therapies for relapsed or refractory (R/R) AML have been introduced, poor outcomes remain, requiring the need for novel approaches. One novel approach is the use of antibody-drug conjugates (ADCs). We conducted an early phase clinical trial with ASP1235, an ADC targeting FMS-like tyrosine kinase 3. In total, 43 patients with R/R AML were treated with ASP1235. The most common adverse events (AEs) included elevated liver transaminase levels, ocular toxicity, and muscular weakness. Ocular treatment-emergent AEs (TEAEs) were observed in 53 % of patients; most were mild or moderate in severity. The most common ocular TEAEs were blurred vision, dry eye, keratitis, photophobia, and reduced visual acuity. Serious (grade ≥3) ocular TEAEs occurred in 16.3 % of patients, with only 1 patient experiencing grade 4 keratitis. Six patients achieved composite complete remission (complete remission [CR] + CR with incomplete hematologic recovery + CR with incomplete platelet recovery), 2 of whom proceeded to hematopoietic cell transplantation with long-term leukemia-free survival. This trial was registered at www.clinicaltrials.gov as #NCT02864290.