The efficacy of TALVEY monotherapy was evaluated in patients with relapsed or refractory multiple myeloma in a single-arm, open-label, multicenter study, MMY1001 (MonumenTAL-1) (NCT03399799, NCT04634552). The study included patients who had previously received at least three prior systemic therapies, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody. The study excluded patients who experienced T-cell redirection therapy within 3 months, prior Grade 3 or higher CRS related to any T-cell redirection therapy, an autologous stem cell transplant within the past 12 weeks, an allogeneic stem cell transplant within the past 6 months, Eastern Cooperative Oncology Group (ECOG) performance score of 3 or higher, stroke or seizure within the past 6 months, CNS involvement or clinical signs of meningeal involvement of multiple myeloma, and plasma cell leukemia, active or documented history of autoimmune disease (exception of vitiligo, resolved childhood atopic dermatitis, resolved Grave's Disease that is euthyroid based on clinical and laboratory testing).
Patients treated with the weekly dosing schedule received step-up doses of 0.01 mg/kg and 0.06 mg/kg of TALVEY followed by TALVEY 0.4 mg/kg subcutaneously weekly thereafter.
Patients treated with the biweekly (every 2 weeks) dosing schedule received step-up doses of 0.01 mg/kg, 0.06 mg/kg, and 0.3 mg/kg (0.75 times the recommended step-up dose 3) of TALVEY followed by TALVEY 0.8 mg/kg subcutaneously biweekly, thereafter. Patients on both dosing schedules were treated until disease progression or unacceptable toxicity.
The efficacy results from the 187 patients treated with TALVEY who were not exposed to prior T cell redirection therapy and who had received at least 4 prior lines of therapy are presented below; of these patients, the median age was 67 (range: 38 to 86) years, 57% were male, 90% were White, 5% were Black or African American, 3% were Asian, and 8% were Hispanic. Patients had received a median of 5 (range: 4 to 13) prior lines of therapy, and 78% had received prior autologous stem cell transplantation (ASCT). Ninety-four percent (94%) of patients were refractory to their last therapy, and 73% were refractory to a proteasome inhibitor, immunomodulatory agent, and anti-CD38 antibody. The International Staging System (ISS) at study entry was Stage I in 44%, Stage II in 34%, and Stage III in 22% of patients. High-risk cytogenetic factors (presence of t(4:14), t(14:16), and/or del(17p)) were present in 29% of patients; baseline cytogenetic data were not available in 11% of patients. Twenty-two percent (22%) of patients had extramedullary plasmacytomas.
Efficacy was based on overall response rate (ORR) and duration of response (DOR) as assessed by an Independent Review Committee using IMWG criteria. The median duration of follow-up from first response among responders receiving TALVEY 0.4 mg/kg weekly was 13.8 (range: 0.8 to 15.4) months.
The median duration of follow-up from first response among responders receiving TALVEY 0.8 mg/kg biweekly was 5.9 (range: 0 to 9.5) months; an estimated 85% of responders maintained response for at least 9 months.
The median time to first response was 1.2 (range: 0.2 to 10.9) months and 1.3 (range: 0.2 to 9.2) months for 0.4 mg/kg weekly and 0.8 mg/kg biweekly (every 2 weeks), respectively.
Thirty-two patients were exposed to prior T cell redirection therapy and had received at least 4 prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody received TALVEY at the 0.4 mg/kg weekly dose. Patients had received a median of 6 (range: 4 to 15) prior therapies, with 81% exposed to CAR-T cell therapy and 25% exposed to a bispecific antibody. Ninety-four percent of patients were exposed to prior T cell redirection therapy directed at BCMA. The ORR per IRC assessment was 72% (95% CI: 53%, 86%). With a median duration of follow-up of 10.4 months, an estimated 59% of responders maintained response for at least 9 months.