C062 | FIRST RESULTS FROM REALITAL: A EUROPEAN MULTICOUNTRY OBSERVATIONAL RETROSPECTIVE STUDY OF TALQUETAMAB IN PATIENTS WITH RELAPSED/REFRACTORY MULTIPLE MYELOMA OUTSIDE OF CLINICAL TRIALS

Talquetamab is the first approved bispecific monoclonal antibody targeting GPRC5D and CD3 for triple-class exposed relapsed/refractory multiple myeloma (RRMM). With a median follow up of 29.8 months (QW), 23.4 months (Q2W), and 20.5 months (prior TCR), the phase 1/2 trial MonumenTAL-1 (N=375) showed an overall response rate (ORR) of 74.1% for QW, 69.5% for Q2W, and 66.7% for prior TCR, respectively. The median duration of response (DOR) was 9.5 months for QW and 17.5 months for Q2W, respectively. We report the first results of REALiTAL, a retrospective observational study of patients receiving talquetamab in a broader population who may not have been eligible for clinical trials. Data were collected from patient medical records, including demographics, disease characteristics, prior therapies, effectiveness, and safety. Informed consent was obtained for all patients. A total of 93 patients from 26 sites in 7 different countries, most from a preapproval access program, were included in the study. The median age was 65 years with a median of 5 prior lines of therapy. Most patients were triple-class (97.8%) and penta-class exposed (86%); 69.9% and 39.8% were triple-class and penta-class refractory, respectively. 52.3% had previously received anti-BCMA treatments (CAR-T, 11.8%; bispecific antibody, 23.7%; antibody-drug conjugate, 25.8%). With a median follow-up of 15 months (range, 0.4–25.3), ORR was 66.7% with 57% of patients achieving ≥VGPR. Median PFS was 8.18 months (6.1–10.7) and median OS was 25.3 months (17.3–not estimable [NE]). Median time to first response was 1.17 months (0.9–1.3) with a median time to best response of 3.6 months (2.7–4.9). Median DOR was 12.3 months (7.9–NE) with a median treatment duration of 7.9 months (5.7–9.9). Patients achieving ≥VGPR had longer median DOR of 13.4 months (8.3–NE) with median PFS and OS of 18.2 months (10.6–NE) and 25.26 months (NE–NE), respectively. Most common adverse events were skin/nail toxicity (all grade [gr], 67.7%; gr 3/4, 1.1%), oral toxicity (all gr, 66.7%; gr 3/4, 3.3%; dysgeusia, 39.8%), CRS (all gr, 55.9%; gr 3/4, 1.1%), and infections (all gr, 47.3%; gr 3/4, 8.6%). 6 patients (6.5%) had TEAEs which led to treatment discontinuation. REALiTAL shows similar clinical outcomes as those observed in MonumenTAL-1 in a hard-to-treat, heavily pretreated patient population. The results align with past findings: a deep response to talquetamab is linked to prolonged DOR, PFS, and OS.