Background: F182112 is a BCMA x CD3 bispecific antibody that redirects CD3+ T cells to mediate T-cell activation and subsequent lysis of BCMA-expressing myeloma cells.NTP-F182112-001 is a First-in-human, Open-label, Multiple center Phase 1 Dose-Escalation Study to Evaluate Safety, Tolerability, Pharmacokinetic, Immunogenicity, and Preliminary Efficacy of F182112 in Patients with Relapsed or Refractory Multiple Myeloma. Clinical trial information: NCT04984434. Methods: Eligible patients aged ≥ 18 years had received at least 2 prior multiple myeloma treatment regimens (not including autologous stem cell transplant) including a proteasome inhibitor, an immunomodulatory agent. Three dose cohorts (0.01, 0.1, and 0.3μg/kg) were planned for accelerated titration phase and the following dose cohorts (3, 10,20, and 30 μg/kg) were planed for the i3+3 dose escalation phase. F182112 were administered as QW or Q2W IV infusion. The primary endpoint was safety and tolerability assessed throughout the study by monitoring AEs per the CTCAE 5.0, except CRS per ASTCT 2018. Results: As of Feb 2,2023, 16 pts in the first 7 cohorts received F182112 (0.01-20 μg/kg). Median follow-up was 3.1 mo (range 0.9–11.7; median age 64 y [range 52–74]; 68% female). 9 (56%) pts had received ≥4 prior lines of therapy and 12 (75%) pts were refractory to last lines of therapy. The ORR was 43.8% (95% CI 19.8-70.1) among all enrolled patients (7/16). Of the 9 pts treated with ≥ 10 μg/kg F182112, 6 pts achieved a partial response (PR) or better (overall response rate; 66.7%), including 2 (22.2%) with a very good partial response or better.The most common treatment-related AEs were CRS (81%), lymphopenia (75%; grade 3/4: 69%), neutropenia (63%; grade 3/4: 44%), leukopenia (56%; grade 3/4: 50%), and anemia (31%). CRS and anemia events were all grade 1–2 and median duration time to CRS was 2 days (1-5). One dose-limiting toxicities (transient ALT elevation, grade 3) occurred at the dose group of 10 μg/kg. No pts required a F182112 dose reduction due to AEs. Conclusions: F182112 provides a novel immunotherapy approach for the treatment of Relapsed/ Refractory Multiple Myeloma that may yield improved clinical efficacy in heavily pretreated pts. Clinical trial information: NCT04984434.