What does this score mean?
The results come from clinical trials and include objective functional endpoints; however, there is no control group, the sample size is small, and the data at this stage are based on topline results in a company press release. Interpretation should remain cautious until full peer-reviewed data are published.
What did the study investigate?
It investigates the durability of clinical response and safety of the autologous, CD19-targeted CAR-T cell therapy mivocabtagene autoleucel (miv-cel, KYV-101) following a single dose in patients with stiff person syndrome (SPS) and generalized myasthenia gravis (gMG).
How was it conducted?
KYSA-8 is a single-arm registration Phase II trial in 26 adult SPS patients who previously had an inadequate response to at least one immunotherapy. The Phase II portion of KYSA-6 is a single-arm, open-label, multicenter study involving 7 patients with moderate-to-severe gMG.
What was found?
In the SPS group at month 12, the median improvement in 25-foot walk time was reported as 49% from baseline (p<0.0001). In the primary analysis, 95% of those who showed clinically meaningful improvement sustained the benefit, and 92% of patients remained free from chronic SPS immunotherapies.
In the gMG Phase II group, at week 24, all 7 patients demonstrated clinically meaningful improvements in MG-ADL and QMG scores; mean changes were -8.3 and -11.7 points, respectively. At last follow-up, 6 of the 7 patients were free of immunosuppressive therapy.
Limitations of the study
These results are not yet a full peer-reviewed article; they are based on the company’s topline release dated September 24, 2026. Both Phase II cohorts are uncontrolled. The gMG sample size is only 7 individuals. Longer and larger follow-up is required for rare or delayed CAR-T toxicities.
What does it mean clinically?
One of the most notable areas for CAR-T beyond cancer is the long-term reprogramming of the immune system in B-cell-mediated autoimmune diseases. These data reinforce the potential of this approach; they do not signify standard clinical practice or a general treatment for autoimmune diseases.
What do we not know yet?
Superiority over standard therapy in a randomized comparison, long-term relapse rates, hypogammaglobulinemia/infection burden, malignancy risk, cost-effectiveness, and which patient phenotype responds best remain unclear.
Source
Kyverna Therapeutics. Positive One-Year Data Demonstrating Durable Clinical Responses and Favorable Safety Profile for Miv-cel in Stiff Person Syndrome and Generalized Myasthenia Gravis. September 24, 2026. Official topline data release.
Related readings: Guide to CAR-T in Autoimmune Diseases · Cell Therapies · Stem Cell Therapies and Clinical Evidence
Written and medically reviewed by: Dr. Kerem Çağlayan · All Scientific Research
Detailed assessment
Safety signal
In the company release, no high-grade CRS, ICANS, or IEC-HS was reported during the SPS and gMG follow-ups. While this is a positive signal, the small sample size cannot rule out rare events.
Next step
For gMG, a randomized Phase III portion of approximately 60 patients is reported to be underway. This comparative data will be far more critical in determining its clinical place.
Medical evaluation note: This content has been prepared for the purpose of interpreting scientific data; it is not a personal diagnosis or treatment recommendation.
