Oncology Learning NetworkVibecotamab Treatment at Dose-Optimized Schedule Shows Promise Among Patients with R/R AML

Vibecotamab in CD123-expressing malignancies has shown potent dose-dependent killing of CD123+ tumor cells in vitro and in vivo.

In a recent phase 1 trial, vibecotamab, a bispecific antibody, has demonstrated a favorable safety and efficacy profile in patients with relapsed/refractory acute myeloid leukemia (AML). This study, led by Farhad Ravandi, MD, at The University of Texas MD Anderson Cancer Center, offers new insights into the potential of targeted monotherapies in a patient cohort with limited treatment options.

Key Points:

• Vibecotamab, a humanized bispecific antibody, was evaluated in a phase 1 trial for its safety and efficacy in patients with relapsed/refractory (R/R) AML.
• The trial aimed to determine the safety of vibecotamab and identify a maximum tolerated dose/recommended dose for this patient population.
• A total of 120 patients with various leukemia subtypes were treated with vibecotamab, focusing on those with CD123-expressing malignancies.
• The recommended phase 2 dose of vibecotamab includes three step-up doses in the first week to reduce cytokine response syndrome (CRS), followed by weekly dosing.
• CRS was the most common treatment-emergent adverse event, occurring in 59.2% of patients, but was predominantly grade 2 or lower.
• Of the 111 patients with CD123-expressing AML eligible for efficacy assessment, 9% achieved an overall response of morphologic leukemia-free state or better.
• Efficacy was observed only in patients who received a target dose of 0.75 μg/kg or higher, with an overall response rate of 11.5% in this subgroup.
• Responders tended to have lower baseline blast counts in the blood and bone marrow (<25%).
• The study suggests that dose optimization can enhance the safety and tolerability of vibecotamab in R/R AML patients, potentially offering a new therapeutic avenue.

“[In the AML treatment landscape], previous trials using cytotoxic agents were largely unable to improve outcomes significantly, but advancements in molecularly targeted agents have improved outcomes in some patient subsets.”
– Farhad Ravandi, MD, The University of Texas MD Anderson Cancer Center, Houston, Texas, and coauthors

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