Real-World Efficacy and Safety of Teclistamab for Patients with Relapsed or Refractory Multiple Myeloma: Nationwide Retrospective Analysis of the Named Patient Program in Korea

The prognosis for heavily pretreated patients with relapsed or refractory multiple myeloma (RRMM) remains poor. Teclistamab, a bispecific antibody targeting B-cell maturation antigen (BCMA) and CD3, has demonstrated deep and durable responses in triple-class exposed RRMM patients in the MajesTEC-1 trial. To further evaluate the efficacy and safety of teclistamab in Korean patients, we conducted a nationwide retrospective analysis. In August 2022, a Named Patient Program (NPP) for teclistamab was initiated in Korea. The inclusion and exclusion criteria, dosage, treatment schedule, and dose modification protocols were largely consistent with those of the MajesTEC-1 trial. Retrospective data were collected for 42 patients who participated in the program. The median age was 67 years (range, 48-84), and the median number of prior lines of therapy was 6 (range, 3-10). Triple- and penta-class refractoriness were observed in 40.5% and 19.0% of patients, respectively. The overall response rate was 66.7% (28/42); 17 patients (40.5%) achieved a complete or deeper response. With a median follow-up of 16.4 months, the median progression-free survival (PFS) was 14.1 months. Patients with R-ISS stage III exhibited significantly shorter PFS (3.1 months vs. not reached, p=0.041). The 12-month overall survival rate was 61.7%; disease progression and infection were the most common causes of death. Only one patient experienced grade ≥ 3 cytokine release syndrome (CRS), and no cases of immune effector cell-associated neurotoxicity syndrome were reported. Grade ≥ 3 infections occurred in 42.9% (n=18) of patients and frequently led to treatment interruption (n=18). Efficacy outcomes including rapid responses, a high response rate, and prolonged survival duration as well as safety profiles, including the incidence of infections, CRS were comparable to those observed in the MajesTEC-1 trial. Given the historically poor outcomes observed in patients with triple-class exposed RRMM, teclistamab treatment should be strongly considered for these patients.