Cullinan Reports Promising Phase 1 Results for CLN-978 and Velinotamig

Cullinan Therapeutics reported encouraging early Phase 1 data for its autoimmune disease programs, with clinical remissions observed for the CD19xCD3 T-cell engager CLN-978 in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), and complete renal responses reported with the BCMAxCD3 T-cell engager velinotamig in lupus nephritis.

The findings support continued development of both therapies in severe, treatment-refractory autoimmune diseases and highlight the potential of T-cell engagers to deliver deeper and more durable disease control.

Targeting Key Drivers of Autoimmunity

CLN-978 targets CD19-positive B cells, while velinotamig targets BCMA-expressing plasma cells, two immune cell populations that contribute to autoantibody production and chronic inflammation in autoimmune diseases.

Cullinan is evaluating both therapies across multiple autoimmune indications, including RA, SLE, lupus nephritis, and autoimmune cytopenias.

Phase 1 Data Show Promising Activity

In the Phase 1 OUTRACE RA study (NCT06994143), CLN-978 induced DAS28-ESR remission in a patient who had previously failed rituximab. Disease activity improved from a baseline score of 4.0 to 2.2 by Week 4 and remained in remission through Week 8. The response was accompanied by rapid reductions in RA-associated autoantibodies.

In SLE, safety findings from the first three patients receiving a multi-dose regimen were consistent with the favorable profile previously reported in RA. Early improvements in proteinuria among patients with lupus nephritis supported plans for a Phase 2a expansion study beginning in early 2027.

Velinotamig generated encouraging early efficacy in two patients with refractory SLE and lupus nephritis. Both achieved complete renal responses and substantial reductions in disease activity, with SLEDAI-2K scores improving from 16 and 14 at baseline to 0 and 2, respectively, by Week 8.

The therapy was well tolerated, with no reported cases of cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS).

Clinical Implications

Chief Executive Officer Nadim Ahmed said the data support Cullinan’s strategy of developing differentiated CD19- and BCMA-directed T-cell engagers for autoimmune diseases driven by B cells and plasma cells. He highlighted evidence of clinical remissions, deep immune-cell depletion, and encouraging early activity across both programs.

Upcoming Catalysts

Cullinan expects to report additional multi-dose CLN-978 data in RA during the third quarter of 2026 and in SLE during the fourth quarter.

Additional velinotamig data from Genrix Bio’s ongoing SLE study in China are expected later this year. The company also plans to initiate a global Phase 1/2a study in autoimmune cytopenias, including immune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA), in the first quarter of 2027.

Reference

Cullinan Therapeutics Shares New Clinical Data Across Its Portfolio of T Cell Engager Programs Targeting CD19 and BCMA in Autoimmune Diseases | Cullinan Therapeutics, Inc.