Kyverna Takes CAR-T Beyond Cancer as Small-Cap Rivals Race to Solve Safety

The miv-cel filing in stiff person syndrome lands two months after Novartis and Bristol Myers Squibb paused their autoimmune programs. Cabaletta, Cartesian, Adicet and Allogene are each testing a different answer to the safety question.

Kyverna Therapeutics (NASDAQ: KYTX) has completed its Biologics License Application for miv-cel in stiff person syndrome, which the company says is the first filing for a CAR-T cell therapy in an autoimmune disease. The company is seeking priority review under its Regenerative Medicine Advanced Therapy designation and says it is preparing for a potential U.S. launch in 2027. If approved, miv-cel would also become the first approved therapy for SPS, a rare neurologic disorder marked by progressive muscle rigidity and painful spasms.

Every CAR-T therapy the FDA has approved to date treats a blood cancer. Kyverna’s filing asks the agency to accept the same approach, in which a patient’s T cells are engineered to eliminate the B cells that drive disease, for people whose condition is serious but not immediately life-threatening. That shift changes how regulators, physicians and payers will weigh the risks.

An approval would reach well beyond Kyverna. It would set the first FDA precedent for CAR-T outside oncology and the first real test of whether a treatment model built for late-line cancer can work commercially in chronic disease, where a one-time infusion competes with years of existing therapy rather than a terminal prognosis.

Novartis and Bristol Myers Paused Their Programs in September

In early September, Novartis halted autoimmune trials of rapcabtagene autoleucel after three patients died from IEC-HS, a severe hyperinflammatory complication. Bristol Myers Squibb also paused studies of zola-cel after unusual cases of ICANS, a neurotoxicity syndrome, in a lupus trial. Bristol Myers has since attributed those cases to a reagent change in its manufacturing process and expects its trials to resume early next year, according to Endpoints News. The company also disclosed the death of a multiple sclerosis patient from infection following late-onset motor symptoms, which it said was not related to ICANS. “The risk tolerance in autoimmune diseases is going to be lower than in cancer,” Jeff Cohen of Cleveland Clinic told Endpoints.

Kyverna reports that in one-year SPS data, miv-cel produced no high-grade cytokine release syndrome or ICANS and no cases of IEC-HS, with nearly all patients remaining off chronic immunotherapies after a single dose. The primary analysis from the registrational KYSA-8 trial was published in JAMA Neurology. More than 100 patients have received miv-cel across autoimmune diseases. Kyverna ended the third quarter with $170.6 million in cash and marketable securities, which it expects, together with its Oxford Finance loan facility, to fund operations into 2028. Enrollment in its Phase 3 myasthenia gravis trial is on track to complete in mid-2027.

Patient Cells, mRNA or Donor Cells: Three Bets on Safer CAR-T

The developers behind Kyverna are dividing along three approaches. Kyverna and Cabaletta use conventional autologous CAR-T made from each patient’s own cells. Cartesian also starts from each patient’s own cells but engineers them with mRNA, an approach designed for outpatient dosing without preconditioning chemotherapy. Adicet and Allogene are building donor-derived cells that remove the need to manufacture a separate product for every patient. The manufacturing and delivery model may matter as much commercially as the clinical response.

Cabaletta Bio (NASDAQ: CABA) is next among conventional autologous programs with a filing date. Its registrational rese-cel cohort in myositis, covering 17 patients with dermatomyositis and antisynthetase syndrome, is expected to read out in the second half of 2027, with a BLA planned for the first quarter of 2028. The company ended the quarter with $299.4 million in cash, which it says funds operations into the first quarter of 2028, and has opened a second registrational cohort in systemic sclerosis.

Cartesian Therapeutics (NASDAQ: RNAC) could report pivotal data sooner. Descartes-08 is an mRNA-based CAR-T given as six weekly outpatient infusions, without the preconditioning chemotherapy that conventional CAR-T typically requires. The roughly 100-patient Phase 3 AURORA trial in myasthenia gravis is placebo-controlled, with topline data expected in the first quarter of 2027 and a BLA planned for mid-2027.

Off-the-Shelf Cells Remove the Custom Manufacturing Step

Adicet Bio (NASDAQ: ACET) builds prula-cel from gamma delta T cells. At 12 months, 50% of evaluable lupus nephritis patients achieved a complete renal response and 54% of evaluable patients reached DORIS remission, with no CRS above grade 2 and no ICANS, IEC-HS or graft-versus-host disease, according to the company’s third quarter update. Jefferies characterized the efficacy as competitive with cell therapy and antibody comparators. Adicet is preparing a single-arm pivotal study in lupus nephritis and reported $100.9 million in cash, with runway into the second half of 2027.

Allogene Therapeutics (NASDAQ: ALLO) presented first data from ALLO-329, a dual CD19 and CD70 CAR-T, at ACR Convergence on November 9. Eight of 10 patients with skin-predominant systemic sclerosis achieved and maintained at least a five-point improvement in skin score, and nine of 10 remained off background immunosuppression. Across 18 treated patients, the company reported no IEC-HS, ICANS, graft-versus-host disease or grade 3 or higher CRS, including in cohorts that received no lymphodepletion. Allogene reported $388.9 million in cash and investments, with runway into 2029.

Kyverna Leads, With Pivotal Data From Cartesian and Cabaletta Due in 2027

Source: company third quarter 2026 reports. Runway reflects company guidance.

The autoimmune opportunity will not be won on depth of B-cell depletion. The pauses at Novartis and Bristol Myers made clear that efficacy alone will not carry the class. A patient with a chronic disease weighs a one-time treatment against years of immunosuppression, and the designs that win will be the ones safe and simple enough to move beyond specialized cell therapy centers into everyday rheumatology and neurology practice. Kyverna’s filing puts that question before the FDA for the first time. The small caps behind it have each built their programs around a different answer.