Phase 1b teclistamab BCMA×CD3 bispecific T‑cell engager in relapsed/refractory plasmablastic lymphoma.

This Phase 1b, open-label, dose-finding and expansion study sponsored by the National Cancer Institute evaluates subcutaneous teclistamab for patients with relapsed/refractory plasmablastic lymphoma after at least 1 prior line of therapy. Teclistamab (Johnson & Johnson/Janssen) is a BCMA×CD3 bispecific antibody that redirects T cells to kill BCMA-expressing malignant plasmablasts, with the trial focused on safety/tolerability and defining a recommended Phase 2 dose while also tracking preliminary activity with serial PET/CT. (ichgcp.net) Correlative work includes optional biospecimens and planned BCMA IHC scoring on archival tumor to explore whether BCMA level predicts response—important because PBL is biologically close to plasma-cell neoplasms but is treated like an aggressive lymphoma and often lacks a clear targeted standard. For most patients with R/R PBL today, care is multi-agent salvage chemotherapy (often DLBCL- or myeloma-inspired regimens), sometimes radiation for focal control, and transplant when feasible, but outcomes are poor—making a “myeloma-grade” BCMA bispecific a pragmatic repurposing strategy.