Kyverna Therapeutics Announces Positive Interim Phase 2 Data from KYSA-6 Study of KYV-101 in Generalized Myasthenia Gravis at AANEM 2025 Compelling results set new clinical standard in generalized myasthenia gravis (gMG)

Kyverna Therapeutics Announces Positive Interim Phase 2 Data from KYSA-6 Study of

KYV-101 in Generalized Myasthenia Gravis at AANEM 2025

Compelling results set new clinical standard in generalized myasthenia gravis (gMG), increasing

confidence in the Company's registrational KYSA-6 Phase 3 MG trial

100% of patients achieved clinically meaningful responses in MG-ADL and QMG - the co-

primary endpoints of the Phase 3 trial - with mean reductions of -8.0 pts and -7.7 points at 24 weeks

KYV-101 was well-tolerated with no high-grade CRS and no ICANS observed, further

consistent and manageable safety profile of KYV-101

Unprecedented results further reinforce KYV-101's potential to deliver durable, drug-free,

disease-free remission with a single dose

Company to host conference call today, October 29, 2025, at 8:00 am ET

EMERYVILLE, Calif., October 29, 2025 - Kyverna Therapeutics, Inc. (Nasdaq: KYTX), a clinical-stage biopharmaceutical company focused on developing

cell therapies for patients with autoimmune diseases, today announced positive interim data from the Phase 2 portion of the registrational KYSA-6 clinical trial of

KYV-101 in generalized myasthenia gravis (gMG). The data will be shared in an oral presentation today by Srikanth Muppidi, M.D., Clinical Professor, Adult Neurology, Stanford Medicine, at the Myasthenia

Gravis Foundation of America (MGFA) Scientific Session during the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) Annual Meeting in San Francisco, CA.

"With today's results, we are setting a new standard across key clinical outcome measures for gMG, particularly in the depth and durability of

response achieved with just a single dose of KYV-101," said Warner Biddle, Chief Executive Officer of Kyverna Therapeutics. "Patients experienced rapid and unprecedented symptom improvement

without the need for ongoing background therapy. These compelling data build upon our previously reported compassionate use1 experience, further advancing our goal to deliver durable, drug-free,

disease-free remission, and importantly, reinforce our confidence in the KYSA-6 Phase 3 trial design. With the growing body of evidence supporting KYV-101's

promising potential in gMG and across multiple autoimmune indications, we believe we are well-positioned to deliver on a first-in-class neuroimmunology franchise,

while expanding our future growth opportunities."

KYSA-6 Phase 2/3 Clinical Trial Summary and Data

The Phase 2 portion of the registrational KYSA-6 clinical trial is a

single-arm, open-label, multicenter study of KYV-101 in gMG. The primary endpoints were Myasthenia Gravis Activities of Daily Living

(MG-ADL) score at 24 weeks and the incidence and severity of adverse events (AEs). Secondary endpoints included Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis Composite (MGC) scores.

As of the October 3, 2025 data cut-off, six patients with

moderate to severe gMG (mean MG-ADL 11.2, QMG 17.3, MGC 21.8), and an average disease duration of 5.3 years (1.7-13.3) were treated with a single dose of 1 108 KYV-101 CAR+T cells. All patients had failed prior immunosuppressant therapies such as FcRns and complement inhibitors. At data

cut-off, duration of follow-up after KYV-101 infusion was up to 36 weeks.

"Interim results showed that KYV-101 has the potential to deliver rapid, substantial and clinically meaningful

improvements in MG-ADL, QMG, and MGC scores for 100% of patients with a single dose, while also offering the potential for patients to become symptom-free," said Naji Gehchan, M.D., Chief Medical and

Development Officer of Kyverna Therapeutics. "With all patients exceeding the thresholds for our Phase 3 co-primary endpoints, we believe the data further validate the powering and overall design of our

Phase 3 superiority trial. We look forward to initiating enrollment for the Phase 3 portion of the trial by the end of this year, as well as sharing updated data from the Phase 2 portion of the trial next year."

Highlights from the interim Phase 2 trial to be featured in the oral presentation at AANEM include:

"Despite available treatment options, many patients living with gMG continue to experience ongoing

disease burden. Even recently approved novel therapies require frequent and chronic dosing and fail to provide a symptom-free state desired by all patients. Today's results are very promising, as we are seeing that KYV-101 can target gMG upstream at the disease source, through deep, tissue-based B-cell depletion. This is likely a prerequisite to an immune reset, representing a

potentially significant treatment advance in gMG," said Professor Srikanth Muppidi, M.D., Clinical Professor, Adult Neurology, Stanford Medicine.

The KYSA-6 Phase 2 study was amended into a registrational Phase 2/3 study following an

end-of-Phase 2 meeting with the FDA earlier this year.

Conference Call Details

Kyverna management will host a conference call today, Wednesday, October 29, 2025, at 8:00 am ET to review these results.

The conference call and live webcast details and supporting presentation materials will be available on the "Events & Presentations" section of Kyverna's Investor Relations webpage at ir.kyvernatx.com. An

archived replay will also be available.

AANEM Presentation Details

Title: Update on the Phase 2 Part of KYSA-6, an Open-Label, Single-Arm,

Multicenter Study of KYV-101, a Fully Human CD19 Chimeric Antigen Receptor T-Cell Therapy in Generalized Myasthenia Gravis

Presenter: Srikanth Muppidi, M.D., Clinical Professor, Adult Neurology, Stanford Medicine

Date and Time: Wednesday, October 29, 2025, 11:00 AM PT

KYV-101 is a fully human, autologous, CD19 CAR T-cell therapy with CD28 co-stimulation, designed for potency and tolerability, which is under investigation for B-cell-driven autoimmune diseases. With a single administration, KYV-101 has potential to achieve deep B-cell depletion and immune system reset to deliver durable drug-free, disease-free remission in autoimmune diseases.

About Myasthenia Gravis

Myasthenia gravis is a B-cell and antibody-mediated neuromuscular autoimmune disease that causes muscle weakness and fatigue, potentially manifesting in trouble speaking, difficulty chewing and swallowing, shortness of breath, and, most

severely, respiratory failure, which can be life-threatening. MG is caused by autoantibodies produced by B-cells that lead to an immunological attack on critical signaling proteins at the junction between

nerve and muscle cells, thereby inhibiting the ability of nerves to communicate properly with muscles. The symptoms of the disease can be transient and in the early stages of the disease can remit spontaneously. However, as the disease progresses,

symptom-free periods become less frequent and disease exacerbations can last for months. Disease symptoms reach their maximum levels within two to three years of diagnosis in approximately 80% of patients. Up to 20% of MG patients experience

respiratory crisis at least once in their lives4.

About Kyverna Therapeutics

Kyverna Therapeutics, Inc. (Nasdaq: KYTX) is a clinical-stage biopharmaceutical company focused on liberating patients through the curative potential of

cell therapy. Kyverna's lead CAR T-cell therapy candidate, KYV-101, is advancing through late-stage clinical development with registrational trials for stiff

person syndrome and myasthenia gravis, and two ongoing multi-center Phase 1/2 trials for patients with lupus nephritis. The Company is also harnessing other KYSA trials and investigator-initiated trials, including in multiple sclerosis and

rheumatoid arthritis, to inform the next priority indications for the Company to advance into late-stage development. Additionally, its pipeline includes next-generation CAR T-cell therapies in both autologous

and allogeneic formats, including efficiently expanding into broader autoimmune indications and the potential to increase patient reach with KYV-102 using its proprietary whole blood rapid manufacturing

process. For more information, please visit https://kyvernatx.com.

Forward-Looking Statements

Statements in this press release about future expectations, plans and prospects, as well as any other statements regarding matters that are not historical

facts, may constitute "forward-looking statements." The words, without limitation, "anticipate," "believe," "continue," "could," "estimate," "expect,"

"intend," "may," "plan," "potential," "predict," "project," "should," "target," "will," "would" and similar expressions are

intended to identify forward-looking statements, although not all forward-looking statements contain these or similar identifying words. Forward-looking statements in this press release include, without limitation, those related to: the topics to be

discussed at the AANEM annual meeting; KYV-101's potential to deliver durable drug-free, disease-free remission with a single dose; the potential for KYV-101 to

deliver rapid, substantial and clinically meaningful improvements while also offering the potential for patients to become symptom free; Kyverna's potential to deliver on a

first-in-class neuroimmunology franchise; the potential for the interim data to further validate the powering and overall design of Kyverna's Phase 3 superiority

trial; the expected timing for enrolling the first patient in the Phase 3 portion of the registrational MG trial; the trial design for the registrational MG trial; Kyverna's engagement with regulators; the expected timing for reporting updated

data for the Phase 2 portion of the MG trial; and Kyverna's clinical trials, investigator initiated trials and named-patient access data. Actual results may differ materially from those indicated by such forward-looking statements as a result

of various important factors, including: uncertainties related to market conditions, the possibility that results from prior clinical trials, named-patient access activities and preclinical studies may not necessarily be predictive of future

results; intellectual property rights; and other factors discussed in the "Risk Factors" section of Kyverna's most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q that Kyverna has filed or may subsequently file with the U.S. Securities and Exchange Commission. Any forward-looking statements contained in this press release are based on the current expectations of

Kyverna's management team and speak only as of the date hereof, and Kyverna specifically disclaims any obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise.

Investors: InvestorRelations@kyvernatx.com