Cullinan Therapeutics Inc. (NASDAQ: CGEM) reported clinical data for two T cell engager therapies targeting autoimmune diseases. The Cambridge, Massachusetts-based biopharmaceutical company presented results from ongoing Phase 1 trials of CLN-978 for rheumatoid arthritis and systemic lupus erythematosus, and initial data for velinotamig in lupus patients.

In the OUTRACE rheumatoid arthritis trial, CLN-978 achieved clinical remission in one heavily pre-treated patient who had been refractory to rituximab. The patient's DAS28-ESR disease score decreased from 4.0 at baseline to 2.2 at week 4, maintained through week 8. The treatment was associated with rapid reduction in rheumatoid arthritis-related autoantibodies.

For systemic lupus erythematosus patients in the OUTRACE SLE trial, safety data from the first three patients treated with multi-dose CLN-978 showed consistency with the rheumatoid arthritis cohort safety profile. Clinical observations in lupus nephritis patients showed rapid improvement in proteinuria.

Velinotamig, a BCMA-targeting therapy licensed from Genrix Bio, demonstrated clinical activity in two refractory lupus patients. Both patients achieved complete renal response and marked reductions in SLEDAI-2K disease scores from baseline levels of 16 and 14 to 0 and 2 respectively at week 8. The treatment showed no cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome.

The company plans to report additional multi-dose data for CLN-978 in rheumatoid arthritis in the third quarter of 2026 and systemic lupus erythematosus data in the fourth quarter. Cullinan expects to initiate a Phase 2a lupus nephritis expansion in early 2027 and a Phase 1/2a trial in autoimmune cytopenias in the first quarter of 2027.

Data cutoffs were May 20, 2026 for CLN-978 trials and May 15, 2026 for velinotamig studies, according to the company's press release.