Kyverna Therapeutics, Inc. Common Stock Study update

Today's conference call will cover the positive topline one-year data from our KYSA-8 registrational trial of mivocabtagene autoleucel, or miv-cel, formerly referred to as KYV-101 in Stiff Person Syndrome, as well as topline longer-term follow-up data from our KYSA-6 phase II trial in generalized Myasthenia Gravis. I'd like to remind everyone that we will be making forward-looking statements during today's call. These statements reflect our current expectations and beliefs and are subject to risks and uncertainties that may cause actual results to differ materially. Please review our safe harbor statement in our press release and presentation materials and risk factors included in our SEC filings for additional information. Joining us today are Warner Biddle, our Chief Executive Officer, and Naji Gehchan, our Chief Medical and Development Officer.

Warner will start with brief remarks followed by Naji, who will cover our data for Stiff Person Syndrome, or SPS, and generalized Myasthenia Gravis, or GMG. After, Warner will close on our commercial opportunity in Stiff Person Syndrome. Following our prepared remarks, Greg Martini, our Chief Financial Officer, will join for a Q&A session. With that, I'll turn the call over to Warner.

Warner? Thank you, Jessica. Today, we are excited to share longer-term durability and safety data for our lead indications that further reinforce Kyverna's leadership in autoimmune CAR T and our near-term potential to deliver the first approved cell therapy in autoimmune disease, in addition to be the first approved treatment for Stiff Person Syndrome.

Overall, we continue to establish a new benchmark in both durability and safety for the entire field. Across both SPS and GMG, data demonstrated robust and durable efficacy for at least one year following a single dose of miv-cel, with nearly all patients remaining off chronic immunotherapies. Importantly, miv-cel's consistent safety profile was maintained in the one-year follow-up with no high-grade CRS, no high-grade ICANS, and no cases of IEC-HS.

These are remarkable results that continue to define miv-cel's unique construct and differentiated profile, where deep B-cell depletion can support a broad immune reset and durable outcomes that have not been seen before with existing therapies and therapies under development. Today's data bring us one step closer to our mission to deliver transformative therapies with curative potential to free people from the burden of lifelong disease and chronic therapy. We remain on track to complete a rolling BLA submission in Q4 of this year, seeking priority review under our RMAT designation, supporting a potential first-in-class autoimmune CAR T launch in 2027. We expect this to be a compelling rare disease launch in a multibillion-dollar Stiff Person Syndrome market that not only establishes our first-to-market leadership but also lays the foundation for expansion into additional neurologic autoimmune conditions such as gMG and progressive MS.

Further, as our phase III gMG trial advances towards enrollment completion in mid-2027, unprecedented 18-month durability data continue to de-risk the registrational path and strengthen miv-cel's differentiation in the large and growing MG market. Turning to slide 5. Miv-cel's potential first-in-class, best-in-class clinical profile is underpinned by its unique CAR construct, robust clinical data, and a well-established manufacturing process, which I will touch on later. Miv-cel is a next-generation CAR, exclusively licensed from the NIH for autoimmune diseases and specifically engineered for both potency and tolerability. Importantly, it's the only fully human CD19-targeted autologous CAR T-cell therapy with a CD28 costimulatory domain, which enables rapid and potent T-cell activation. This unique construct design continues to bear out in our clinical data across efficacy, safety, and durability, demonstrating deep B-cell depletion, including in targeted tissues, supporting a broad immune reset and the potential for durable remissions.

In fact, the first SPS and gMG patients treated with a single dose of miv-cel under the compassionate use pathway have now achieved durable responses beyond 2 years without the need for chronic immunosuppressive therapies. These outcomes are reinforced across our own clinical trials in Stiff Person Syndrome and gMG, where we're seeing this durability trend continue. To date, more than 100 patients have been treated with miv-cel across multiple autoimmune indications, and we continue to observe consistent and manageable safety profile with no high-grade CRS or ICANS and no reported cases of IEC-HS. These data support the potential for outpatient administration, which is an important consideration for patients, physicians, and healthcare systems. Overall, these outcomes highlight the potential for miv-cel to fundamentally redefine the treatment paradigm for autoimmune diseases. Now let's turn to manufacturing. Next slide. Miv-cel is manufactured using a well-established and validated process like those used for commercially available autologous CD19 CAR T-cell therapies, with a manufacturing success rate exceeding 98% across our clinical trials.

Recently, we signed a commercial agreement with ElevateBio, our primary manufacturing partner for miv-cel, providing the flexibility and scale to support both our commercial transition and ongoing clinical programs. Overall, our unique construct and well-established manufacturing process support a strong miv-cel efficacy and tolerability data generated in now over 100 patients across indications to date. With that, I'll turn the call over to Naji, who will now go over our top-line data.

Naji? One-year follow-up data in SPS, which represent one of the most mature durability data sets reported to date in an autoimmune CAR T clinical trial.

Let's go to slide 8. As a reminder, our FDA-aligned KYSA-8 clinical trial is a single-arm, multicenter, open-label, registrational, phase II trial. We have received both the RMAT and orphan drug designations for miv-cel in SPS. The change from baseline in the timed 25-foot walk test measured at 16 weeks in our primary endpoint. This is a validated test to assess walking ability, as well as to evaluate stiffness and loss of mobility. To put things into perspective, the time that it takes a healthy individual to walk 25 feet is about 4-5 seconds. For patients with SPS, that time can be twice as long or even longer, depending on the severity of their disease.

Our secondary endpoints for measuring disability and stiffness include the modified Rankin scale, or mRS, the Distribution of Stiffness Index, or DSI, and lastly, the Heightened Sensitivity Scale. The trial included 26 patients with follow-up through one year. Importantly, all patients discontinued their immunotherapies prior to a single dose of miv-cel. Let's turn to the data on slide 9. As you recall, we reported positive primary analysis of our KYSA-8 registrational trial at AAN earlier this year, demonstrating statistically significant durable clinical benefit across all primary and secondary endpoints, with reversal of disability scores. In addition, all 26 patients remained off immunotherapies at the 16-week primary endpoint measurement, and miv-cel was well-tolerated. These outcomes achieved with a single dose of miv-cel alone are unprecedented in SPS, a highly debilitating and progressive disease with no approved therapies.

Today, we are reporting data on all 26 patients who have reached the one-year follow-up. As you can see on the chart on the left-hand side, improvement in mobility, as measured by the timed 25-foot walk test supporting reversal of disability, was sustained through one year. Recall, in the primary endpoint measured at 16 weeks, we saw 81% of patients achieve a clinically meaningful improvement in the timed 25-foot walk test. At the one-year follow-up, 95% of patients maintained their benefit, with nearly all patients, or 24 out of 26, remaining off immunomodulatory or immunosuppressant therapies for SPS. At baseline, the median timed 25-foot walk was 11.1 seconds.

At the 16-week primary endpoint, the median reduction in timed 25-foot walk was 46%, and this was further improved to a 49% reduction from baseline at one year, representing an over twofold improvement of what is considered a clinically meaningful improvement of at least 20%. These improvements translate to more than one-third of patients achieving a timed 25-foot walk of less than 5 seconds, which is consistent with a healthy adult walking speed. Importantly, of the 12 patients who required a walking aid prior to treatment, 67% continued to walk unassisted at one year, further highlighting miv-cel's durable efficacy and potential to reverse disability. The magnitude of improvement and the durability of outcomes are unlike anything else that has been observed in SPS and marks an important milestone for patients who are desperate for an approved therapy that has the potential to reverse the course of their disease.