Kyverna Stock Rockets After Cell Therapy Helps Patients Walk Again In Rare Disorder

Kyverna Therapeutics, Inc. (NASDAQ:KYTX) stock rose Monday, with a session volume of 6.80 million compared to the average volume of 696.68 thousand as per data from Benzinga Pro. The clinical-stage biopharmaceutical company shared topline data from the KYSA-8 Phase 2 trial of mivocabtagene autoleucel (miv-cel, formerly KYV-101) in stiff person syndrome (SPS). Miv-cel is a fully human, autologous CD19-targeting CAR T-cell therapy with CD28 co-stimulation. Also Read: Kyverna Sets Pace In Race For Autoimmune CAR-T Approval By 2026 Stiff Person Syndrome is a rare autoimmune neurological disorder causing progressive muscle stiffness, rigidity, and painful spasms, primarily in the torso and limbs, triggered by stimuli like noise or touch, leading to falls and disability as it worsens over time. It results from the immune system mistakenly attacking nerve cells controlling muscle movement. The single-arm registrational Phase 2 trial dosed 26 patients who had an inadequate response with non-approved treatment options, and received a single dose of miv-cel. The patients were dosed and followed through the primary analysis time point (Week 16) with additional follow-up thereafter. Data After a single dose, miv-cel achieved statistically significant benefits on primary and all secondary efficacy endpoints at Week 16. Primary Endpoint: Miv-cel demonstrated a robust and sustained improvement in mobility with a highly statistically significant improvement in timed 25-foot walk (T25FW). The median improvement was 46% at Week 16 as compared to baseline. 81% of patients exceeded a 20% improvement in T25FW, a threshold considered clinically meaningful. Secondary Endpoints: A highly statistically significant benefit was also achieved across all secondary endpoints, including the Modified Rankin Scale (mRS), Distribution-of-stiffness Index (DSI), Hauser Ambulation Index (HAI), and Heightened Sensitivity Scale (HSS). Of the 12 patients who required a walking aid device before treatment, 67% no longer needed assistance to walk at Week 16. 100% of patients remained free of immunotherapies, and no patients required rescue therapy as of the last follow-up. Miv-cel was well-tolerated, with no high-grade cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS) observed. Next Steps Kyverna plans to submit a Biologics License Application (BLA) to the FDA for SPS in the first half of 2026. It has received both Regenerative Medicine Advanced Therapy and Orphan Drug designations for miv-cel in this indication. The company also plans to share the full SPS data set at a medical conference in 2026. KYTX Price Action: Kyverna Therapeutics shares were up 38.15% at $12.13 at the time of publication on Monday. The stock is trading at a new 52-week high, according to Benzinga Pro data. Read Next: Trump Skeptical If His Economic Policies Would Sway Voters In 2026 Midterms: ‘I Can’t Tell…’ Photo via Shutterstock