📰 What This Document Is 🔬

This filing is an 8-K report and accompanying press release from Kyverna Therapeutics. It’s an announcement designed to share highly positive, long-term clinical data on their lead drug candidate, miv-cel. Generally, an 8-K is used to announce material, significant news to investors. Here, the key message is that their single-dose treatment shows sustained, profound efficacy for patients with generalized myasthenia gravis (gMG).

👉 The headline finding is the demonstration of deep and durable clinical responses—meaning the benefits last a long time—up to 52 weeks after just one infusion of miv-cel.

🏢 What Kyverna Therapeutics Does 🧬

Kyverna is a late-stage biopharmaceutical company focused entirely on cell therapies. In simple terms, they are developing highly advanced, customized cellular medicines designed to help patients whose immune systems are mistakenly attacking their own healthy tissues (autoimmune diseases).

• Lead Therapy: Their lead drug is called miv-cel (mivocabtagene autoleucel, KYV-101).
• Mechanism: miv-cel is an autologous CAR T-cell therapy. This means they use the patient's own immune cells, modify them in a lab to make them "better at fighting a specific enemy" (B-cells), and then re-infuse those enhanced cells back into the patient.
• Goal: They aim to achieve deep, durable, and drug-free remission across multiple autoimmune conditions, particularly those driven by B-cells.

🌐 Understanding Generalized Myasthenia Gravis (gMG) 🌬️

For a reader unfamiliar with the disease, Myasthenia Gravis (MG) is an autoimmune neuromuscular problem. It causes fluctuating muscle weakness and fatigue because the immune system mistakenly attacks the connection points between nerves and muscles.

• The Problem: This attack is usually mediated by autoantibodies produced by B-cells.
• The Impact: While it can affect the eyes, gMG involves muscles beyond the eyes, potentially impacting breathing, swallowing, and limb function.
• Current Challenge: Because the disease is chronic, most patients require continuous, ongoing immunosuppressant medications to control symptoms.
• Scope: An estimated 80,000 patients in the U.S. are diagnosed with gMG, and the disease often progresses, requiring lifelong treatment.

🧪 The Drug: miv-cel (KYV-101) 🌟

miv-cel is a breakthrough therapy specifically designed to treat B-cell-driven autoimmune diseases with a single administration. It is described as a fully human, autologous, CD19-targeting CAR T-cell therapy.

• Action: By targeting CD19, the therapy aims to perform a profound depletion of B-cells—the type of cell that produces the harmful autoantibodies in MG.
• The Promise: The goal of this "immune reset" is to achieve remission that does not require the patient to take immunosuppressant drugs daily.
• Development Status: KYTX is advancing miv-cel for its neuroimmunology franchise, with current indications in stiff person syndrome and generalized myasthenia gravis.

🔬 Long-Term Efficacy Results in gMG 🏆

The company presented updated data from the Phase 2 portion of the KYSA-6 registrational trial. This data tracked the drug's performance over a prolonged period (up to one year), which is extremely important for measuring durability.

• Initial Cohort: The analysis included 7 patients with moderate-to-severe gMG. These patients were all resistant to prior standard treatments, including other biologics and immunosuppressants.
• Key Performance: 100% of patients achieved rapid, robust, and sustained improvements in core functional measures (MG-ADL and QMG).
• Measurable Improvements: At Week 24, the patients showed substantial average reductions in their scores:
  • MG-ADL scores dropped by -8.5 points.
  • QMG scores dropped by -11.3 points.
• Durability Check: The beneficial response was shown to be sustained out to 52 weeks in the three patients who had follow-up data available.
• Functionality: 57% of patients achieved "minimal symptom expression" (defined as an MG-ADL score of 0 or 1) at their last follow-up, signaling a deep functional improvement.

🔄 Status of Immunosuppression-Free State 🌿

One of the most critical outcomes reported is the ability of the drug to normalize the immune system without ongoing drug support.

• Sustained Freedom: Through Week 24, 100% of patients were free of high-dose steroids, nonsteroidal immunosuppressants, and other biologics (like FcRns and complement inhibitors).
• Why This Matters: This indicates that the therapy may restore the patient's ability to manage the disease on its own, which is the ultimate goal for chronic autoimmune care.

⚙️ Biomarker and Safety Data 🛡️

The report provided supporting data showing how the drug worked mechanically, as well as how safe it was to administer.

• Mechanism of Action: The therapy caused robust expansion of T-cells and deep depletion of B-cells—a process referred to as an "immune reset." This depleting the faulty cell population is the mechanism that leads to symptom relief.
• Autoantibodies: The data showed reduced levels of autoantibodies while simultaneously preserving the patient's general "humoral immunity," which is a positive sign that the immune system hasn't been harmed.
• Safety Profile: The treatment was reported as well-tolerated, with no high-grade Cytokine Release Syndrome (CRS) or Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS) events.
• Expected Side Effects: Two patients had temporary Grade 3/4 neutropenia (low white blood cell count), which the company stated were expected side effects following the required lymphodepletion process for CAR T-cell therapy.

🗣️ Executive and Investigator Commentary ✨

The enthusiasm from both the company's leadership and the academic investigators participating in the trial was highly emphasized, lending significant confidence to the findings.

• Kyverna CEO Warner Biddle: Stated that the updated data reinforces the drug's "differentiated profile," which strengthens the company's conviction regarding the ongoing Phase 3 trial.
• Kyverna CDMO Naji Gehchan: Highlighted that the profound results are driven by miv-cel's unique ability to "target the disease at the source," achieving durable drug-free remission.
• Prof. Srikanth Muppidi (Stanford Medicine): Noted that the ability of miv-cel to achieve minimal symptom expression while eliminating the need for chronic therapies represents a "meaningful clinical advancement" for patients.

🚀 Clinical Trial Progress and Future Plans 🗓️

The company is actively advancing the drug through the most rigorous stages of clinical testing and is expanding its scope.

• KYSA-6 Trial: This original Phase 2 portion was amended into an FDA-aligned registrational Phase 2/3 trial back in 2025. The company is currently enrolling patients in the Phase 3 portion of this study.
• Scale: The Phase 3 trial is active at 14 clinical sites across three different geographies.
• Pipeline Expansion: Kyverna plans to use its initial success to further inform future indications, such as studying the therapy in multiple sclerosis and rheumatoid arthritis.
• Stiff Person Syndrome (SPS): The company announced that at the upcoming conference call, they will also present updated data from the KYSA-8 trial, which is evaluating miv-cel for stiff person syndrome (SPS).

📞 Upcoming Meetings and Investor Relations 🗓️

Investors and media interested in these results should note the scheduled conference call and related presentation dates.

• Conference Call: Kyverna will host a conference call on Wednesday, April 22, 2026, at 7:00 am ET. This call will review the current gMG results and the SPS data.
• AAN Presentation: The main data presentation will take place at the American Academy of Neurology (AAN) Annual Meeting on Monday, April 20, 2026, at 1:48 PM CT (Oral Presentation).
• Investor Website: All presentation materials and links for the conference call can be found on the "Events & Presentations" section of the Investor Relations webpage: ir.kyvernatx.com.
• Contact Information:
  • Investors: [email protected]
  • Media: [email protected]

---

🧠 The Analogy 💡

Think of generalized myasthenia gravis as a complex garden that is being overgrown by aggressive, invasive weeds (the autoantibodies). Instead of just spraying the weeds with temporary herbicides (daily immunosuppressant drugs), Kyverna's miv-cel acts like a highly targeted biological specialist. It enters the garden, specifically finds the root cause of the weed generation (the B-cells), and removes them entirely. Because the source is cut out, the garden can then self-regulate and thrive again, without needing continuous intervention.

🧩 Final Takeaway ✨

Kyverna provided strong evidence that miv-cel can provide deep, long-lasting remission for gMG with a single infusion, moving the treatment paradigm away from lifelong drug dependence. The focus now shifts to the success of the global Phase 3 trial and the expansion of miv-cel into additional autoimmune diseases.