SP23 | SINGLE-CENTER EXPERIENCE IN THE TREATMENT OF RELAPSED/REFRACTORY MULTIPLE MYELOMA WITH BISPECIFIC ANTIBODIES: OUTCOMES AND EFFICACY

Multiple myeloma (MM) treatment has advanced with proteasome inhibitors, immunomodulators, and monoclonal antibodies, yet remains incurable due to resistant clones, especially in penta-refractory patients with poor prognosis. Bispecific antibodies (BsAbs) offer a promising approach, delivering deep, durable responses and emerging as a key strategy with potential use in earlier treatment lines. Since February 2023, four patients at our center have been treated with BsAbs , two with Teclistamab ( TEC) and two with Talquetamab (TAL), all of whom were diagnosed with refractory relapsed Multiple Myeloma and penta-refractory disease. Notably, one patient also had extraosseous disease, highlighting the complexity and severity of their condition. Among the two patients treated with TEC, one is currently on the 16° cycle of therapy, and the other on the 23° cycle. One of these patients had previously received an anti-BCMA therapy (Belantamab) as part of their treatment regimen. Both patients achieved a complete response (CR) to the disease, with the first CR occurring 4 months after starting BsAbs treatment. Notably, neither patient developed CRS or ICANS. However, one patient experienced an infectious episode due to Haemophilus, which was quickly resolved, while the other developed prolonged neutropenia, necessitating the use of GCSF and a two-month interruption in therapy. For the other two patients receiving TAL, one is on the 16° month of treatment, and the other on the 8° month. The first patient is in CR, while the second patient has achieved a PR, the first CR occurred at 4 months. Both patients experienced dysgeusia as the major toxicity, with one also developing onychodystrophy Importantly, there were no episodes of CRS or ICANS in these patients either. In terms of supportive care, all patients received immunoglobulin replacement therapy via intravenous administration if their IgG levels fell below 400 mg/dL In conclusion, BsAbs have demonstrated substantial clinical benefit for relapsed Multiple Myeloma patients, providing deep and durable responses. The clinical outcomes observed in our cohort of patients, including high rates of complete response and manageable toxicities, reinforce the growing role of BsAbs as a promising therapy for this challenging patient population. The ongoing evaluation of their long-term efficacy and safety will be crucial in defining their role in future treatment strategies for MM.