A subcutaneous injection of the BCMAxCD3 bispecific antibody teclistamab was found to be safe and elicited responses in a majority of patients with relapsed or refractory multiple myeloma, according to findings from a multi-institutional phase I study presented by Alfred L. Garfall, MD, and colleagues at the 2020 American Society of Hematology (ASH) Annual Meeting & Exposition (Abstract 180).

Of 22 patients treated with the injection dose of teclistamab, who were also chosen for the phase II study, 74% experienced a partial response or better.

Alfred L. Garfall, MD

Teclistamab is a bispecific antibody that activates T cells to attack multiple myeloma cells expressing B-cell maturation antigen (BCMA). These updated results from the phase I trial show, for the first time, the safety and efficacy of the more convenient injectable form of the drug, which was previously reported to be safe and elicit responses when administered intravenously in May 2020.

“These are exciting results for [patients with] multiple myeloma,” said Dr. Garfall, Assistant Professor of Medicine in the Division of Hematology-Oncology at the Perelman School of Medicine at the University of Pennsylvania. “To have a single, subcutaneous-injectable drug that is effective in patients whose disease had become resistant to so many prior therapies, is well tolerated, and often yields long-lasting responses is a promising achievement.”

Results

Patients who received both the injection (n = 65) and infusion (n = 84) experienced side effects commonly associated with immune-boosting drugs. Grade 1 or 2 cytokine-release syndrome occurred in 54% and 57% of patients with intravenous and subcutaneous dosing, respectively, and typically occurred 1 to 2 days after the drugs were administered.

Other side effects included anemia (in 55% of patients), neutropenia (57%), thrombocytopenia (40%), and leukopenia (28%). Side effects significantly subsided after the first 2 weeks, and all events were considered within a manageable safety profile, said the authors.

The overall response rate among the 68 patients treated with the most active intravenous and subcutaneous doses was 69%, including 59% with very good partial responses or better and 26% with complete responses or better.

Among 47 patients who responded to teclistamab at the most active dose levels, 94% remain on teclistamab after a median follow-up of 6.5 months, with some ongoing responses lasting up to 21 months in duration.

“Teclistamab takes a similar approach to cellular therapies, which genetically engineer a patient's T cells to find and destroy cancer cells,” explained Dr. Garfall. “Except, this is jump-starting the immune system with a single, off-the-shelf drug that takes 15 minutes to administer, in contrast to cellular therapies that take several weeks to manufacture for each patient.”

Disclosure: For full disclosures of the study authors, visit ash.confex.com.