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

Purpose The prognosis for heavily pretreated patients with relapsed or refractory multiple myeloma (RRMM) remains poor. Teclistamab, a bispecific antibody targeting B-cell maturation antigen and CD3, has demonstrated deep and durable responses in tripleclass–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. Materials and Methods In August 2022, a Named Patient Program 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. Results The median age was 67 years (range, 48 to 84 years), and the median number of prior lines of therapy was 6 (range, 3 to 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 revised International Staging System 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). Conclusion 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.