Cullinan Therapeutics reports remissions in SLE and RA with CD19 TCE
Cullinan Therapeutics has presented new interim clinical data from its dual T cell engager portfolio at its Immunology Day event, reporting clinical remissions and deep B cell depletion across multiple autoimmune indications in patients who had failed prior therapies.
The Cambridge, Massachusetts-based company shared data from its Phase 1 OUTRACE trials of CLN-978, a CD19xCD3 bispecific T cell engager, alongside early findings from velinotamig, a BCMAxCD3 candidate in-licensed from China's Genrix Bio. Both datasets carry data cut-offs from mid-May 2026.
CLN-978: remissions in RA and SLE signals
In the OUTRACE RA trial, the first multi-dose cohort included two heavily pre-treated, poly-refractory patients. One, who had previously failed rituximab, achieved DAS28-ESR remission, with a baseline disease score of 4.0 falling to 2.2 by week four and sustained at week eight. The company reported that remission was accompanied by rapid reduction in RA-associated autoantibodies. Safety data from the first three SLE patients on the multi-dose regimen were described as consistent with the favourable profile observed in RA.
Cullinan also noted rapid improvement in proteinuria among SLE patients with nephritis, which it said supports a planned Phase 2a expansion into lupus nephritis, expected to begin in early 2027. Additional multi-dose RA data are expected in Q3 2026, with SLE data to follow in Q4.
President and chief executive Nadim Ahmed said the results supported "the potential for CLN-978 to deliver durable, treatment-free remissions in the community out-patient setting, representing a meaningful shift in how these diseases may be managed."
Velinotamig: complete renal responses in lupus nephritis
Initial data from two refractory SLE patients treated with four intravenous doses of velinotamig showed marked clinical improvement. Both patients achieved complete renal responses; SLEDAI-2K scores fell from 16 and 14 at baseline to 0 and 2, respectively, at week eight. Crucially, no cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome was observed in either patient — a notable finding given that these toxicities have been a limiting factor in T cell engager development more broadly.
Cullinan plans to initiate a Phase 1/2a basket trial in autoimmune cytopenias — including immune thrombocytopenia and autoimmune haemolytic anaemia — in Q1 2027.
Market context and competitive landscape
The T cell engager space in autoimmune disease has attracted significant clinical and commercial interest over the past two years, partly on the back of dramatic early results with anti-CD19 CAR-T in conditions such as SLE and myasthenia gravis. Bispecific formats like Cullinan's offer the potential for off-the-shelf delivery and outpatient administration — advantages over cell therapies that require complex manufacturing and hospitalisation.
Cullinan is not alone in pursuing this approach. A number of companies, including larger pharma players and university spin-outs, are advancing CD19-targeting and BCMA-targeting bispecifics in rheumatology. The field as a whole faces the challenge of demonstrating that T cell engager-induced remissions are durable and that the safety profiles observed in small early cohorts hold at scale. Regulators, including the FDA and EMA, have yet to establish clear approval pathways specifically for T cell engagers in autoimmune indications, which may influence trial design requirements as programmes advance into Phase 2 and beyond.
The data presented today remain early-stage and interim; cohort sizes are small, and longer follow-up will be needed to assess durability and safety at larger scale. Investors will be focused on the Q3 and Q4 data readouts as the clearest near-term signal of whether these initial responses are sustained.