The FDA granted for treating adults with relapsed or refractory multiple myeloma who have received at least four prior lines of therapy, drug developer Janssen announced Thursday.
The first-in-class bispecific T-cell-engaging antibody against CD3 and GPRC5D was approved as a weekly or biweekly subcutaneous injection after an initial step-up phase.
Approval was based on 187 patients from MonumenTAL-1 -- a -- who had received at least four prior lines of therapy including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 antibody, and had no previous exposure to T-cell redirection therapy.
The study -- which assessed the drug at different dosing regimens -- showed that patients treated at a biweekly dose of 0.8 mg/kg achieved an overall response rate of 73.6%. With a median follow-up of nearly 6 months from first response, 58% of patients achieved a very good partial response (VGPR) or better, including 33% who achieved a complete response or better.
At the weekly dose of 0.4 mg/kg, 73% of patients achieved an overall response. With a median follow-up of nearly 14 months from first response, 57% of patients achieved a VGPR or better, including 35% who achieved a complete response or better.
Median duration of response was not reached in the 0.8 mg/kg biweekly dose group, and was 9.5 months in the 0.4 mg/kg weekly dose group. Among patients receiving the 0.8 mg/kg biweekly dose, an estimated 85% of responders maintained response for at least 9 months.
The study also included 32 patients exposed to prior bispecific antibody or chimeric antigen receptor (CAR) T-cell therapy (94% with B-cell maturation antigen [BCMA]-directed therapy) who received talquetamab at the 0.4 mg/kg weekly dose. At a median follow-up of 10.4 months, 72% achieved an overall response, with an estimated 59% maintaining the response for at least 9 months.
"The clinically meaningful efficacy and safety profile observed with talquetamab in heavily pretreated patients in this clinical trial, which included patients treated with prior BCMA-targeted bispecific or CAR T-cell therapy, has been notable," said study investigator Ajai Chari, MD, of the University of California San Francisco, in the press release. "Patients at this stage of disease have a poor prognosis. Talquetamab as a first-in-class therapy is a new option for patients with this difficult-to-treat blood cancer."
for talquetamab includes a boxed warning for cytokine release syndrome (CRS) and neurologic toxicity, including immune effector cell-associated neurotoxicity syndrome. Because of these risks, talquetamab will only be available through a risk evaluation and mitigation strategy (REMS) program.
In trials, the most common adverse reactions (≥20%) were pyrexia, CRS, dysgeusia, nail disorder, musculoskeletal pain, skin disorder, rash, fatigue, weight reductions, dry mouth, xerosis, dysphagia, upper respiratory tract infection, diarrhea, hypotension, and headache. The most common grade 3/4 laboratory abnormalities (≥30%) reported included decreases in lymphocyte counts, neutrophil counts, white blood cell counts, and hemoglobin.
The most common non-hematologic adverse events seen in the study were oral toxicities, which occurred in 80% of patients, with grade 3 events occurring in 2.1% of patients.
Serious infections occurred in 16% of patients, with fatal infections occurring in 1.5%.