“We have limited treatment options for triple-class exposed and refractory multiple myeloma patients, especially for use in the community,” coauthor Dr. Saad Z. Usmani, of Memorial Sloan Kettering Cancer Center, New York, said in an interview. “Teclistamab is a BCMA directed bispecific antibody that is showing high response rates at the recommended subcutaneous phase 2 doses (RP2D),” and has a strong safety profile, he explained.
Teclistamab tackles two targets – both CD3 on the surface of T cells and B-cell maturation antigen (BCMA) on the surface of myeloma cells – said Dr. Ajay K. Nooka of Emory University, Atlanta, in the meeting presentation. The study was published simultaneously in the New England Journal of Medicine.
After teclistamab showed promising efficacy and an acceptable level of side effects in phase 1, researchers enrolled 165 adults aged 33-84 years with relapsed or refractory multiple myeloma (MM). The patients had experienced at least three previous lines of therapy (LOT). All patients received a weekly subcutaneous injection of 1.5 mg/kg of body weight following step-up doses of 0.06 mg/kg and 0.3 mg/kg. The primary endpoint of the study was overall response.
The median age of the patients was 64 years; 58% were male, 81.2% were White. The median prior LOT was 5; all of the patients were triple-class exposed (100%); 70% were penta-drug exposed, 78% were triple-class refractory, and 30% penta-drug refractory.
The overall response rate (ORR) was 63% over a median follow-up period of approximately 14.1 months. In addition, 39.4% of patients had a complete response or better, and 26.7% had no minimal residual disease, for a negative minimal residual disease rate of 46.2% in patients with complete response. The median durations of response and progression-free survival were 18.4 months and 11.3 months, respectively.
“The ORR was consistent across clinically relevant subgroups, including high cytogenetic risk and penta-drug refractory subgroups,” Dr. Nooka said in his presentation.
The most common adverse event was cytokine release syndrome, which occurred in 72.1% of patients; however, only 0.6% of these events were grade 3, and none were grade 4. Other adverse events included neutropenia in 70.9% (64.2% of events were grade 3 or 4), anemia (52.1%, 37.0% of events were grade 3 or 4, respectively) and thrombocytopenia (40%, 21.2% of events were grade 3 or 4). Infections occurred in 76.4% of patients overall, 44.8% of which were grade 3 or 4, and neurotoxic events occurred in 24 patients (14.5%). The five cases of immune effector cell–associated neurotoxicity syndrome (CRS) were grade 1 or 2.
A total of 2 patients (1.2%) discontinued the study because of adverse events, but no discontinuations or dose reductions occurred as a result of neurotoxic events.
A total of 5 deaths attributed to teclistamab occurred during the study: 2 caused by COVID-19, 1 pneumonia, 1 hepatic failure, and 1 progressive multifocal leukoencephalopathy (PML).
The responses were durable and persisted over time, said Dr. Nooka. At the point of data cutoff, 64.4% of patients who responded maintained that response.
Overall, the data support teclistamab as “a promising new, off-the-shelf, T-cell redirecting therapy targeting BCMA for patients with relapsed or refractory MM,” with phase 3 studies ongoing and early access programs in progress, Dr. Nooka concluded.
“The ORR and durability of response seen with teclistamab is very impressive when one sees the data for other single agents approved for relapsed/refractory MM in the past,” Dr. Usmani said in an interview. “I hope the current data will help get a regulatory approval for the triple class exposed MM population.”
However, potential barriers to widespread use of teclistamab in practice include logistics and a learning curve for practicing hematologists/oncologists, Dr. Usmani noted. “While the CRS appears to be grade 1 or 2 and very manageable, the logistics of giving bispecific antibodies in the community setting and managing CRS during the first cycle of therapy in the community will need to be worked out, and partnership with academic centers that have experience in managing these patients will be needed, he added.
As for additional research, “teclistamab is being combined with other MM therapies and being explored in earlier lines of treatment,” Dr. Usmani said.