Prognosis is poor for patients (pts) with relapsed/refractory multiple myeloma (RRMM; median overall survival: less than 1 year), indicating a clear need to identify agents with novel mechanisms of action. B-cell maturation antigen (BCMA) has recently emerged as a novel treatment target for MM due to its highly selective expression in plasma cells. TNB-383B, a BCMA x CD3 T-cell engaging bispecific antibody, was designed to overcome the toxicity limitations of existing BCMA therapies and has demonstrated promising results in an ongoing first-in-human phase 1 study in pts with RRMM . Herein, we report the updated efficacy and safety outcomes of this phase 1 study.

Conclusions

TNB-383B in pts with RRMM is well tolerated with an ORR of 79% observed at doses greater than or equal to 40 mg in the dose-escalation cohorts. Despite having a shorter follow-up period, this trend was also observed at doses greater than or equal to 40 mg in the combined dose-escalation/expansion cohorts (ORR: 64%). Enrollment into the dose-expansion arm is ongoing; updated data will be presented at the meeting.

ASH 2021: Abstract 900