CAR-T ushers in a new era

The CAR-T industry has witnessed a new landmark event.

On May 12, 2026, Kyverna announced that it had officially submitted a rolling Biologics License Application (BLA) to the FDA for its CAR-T product, KYV-101, for the treatment of Stiff Person Syndrome (SPS).

Looking solely at the indication, SPS is a rare autoimmune disease with limited market potential, and its short-term direct impact on performance and valuation is also limited.

However, the industrial significance of this move far outweighs its commercial scale: this is the world's first CAR-T therapy for an autoimmune disease to be submitted for marketing approval.

For a long time, the market's expectations for CAR-T have extended beyond hematological tumors. After the competition in the hematological tumor market has become increasingly fierce, the next major battlefields in the industry are the super tracks of solid tumors and autoimmune diseases. Now, the industrial progress is being realized along this main line.

For the entire cell therapy industry, the significance of this BLA submission lies more in boosting confidence than in generating short-term substantial benefits. In the long run, once the new era of CAR-T for autoimmune diseases begins, it is bound to arrive at an accelerated pace.

Patients with SPS Await Spring

To some extent, the breakthrough of KYV-101 has actually taken a "shortcut."

Stiff Person Syndrome is a typical ultra-rare disease, with a global prevalence of only 1 - 2 cases per million population, and there are fewer than a thousand patients in the United States. The extremely small patient base means that it is easier to obtain policy support in clinical development and regulatory approval, with more potential "green channels."

From the perspective of disease characteristics, SPS has a strong unmet clinical need.

It is a disabling and progressive autoimmune disease. The symptoms start with stiffness in the trunk and abdominal muscles and gradually spread to the limbs and face. In the early stage, it presents as intermittent attacks, and in the later stage, it turns into persistent stiffness. Patients will face an increased risk of permanent disability and death.

Data shows that 80% of patients ultimately lose their ability to move independently and need to rely on walking aids or wheelchairs; only 19% of patients can still work normally four years after being diagnosed. Sudden muscle freezing and falls also bring the risk of emergency treatment.

Meanwhile, SPS is often accompanied by multiple comorbidities. More than 80% of patients have other autoimmune diseases such as type 1 diabetes, thyroid diseases, and pernicious anemia. Some patients may also develop refractory epilepsy and cerebellar ataxia, further complicating the condition.

Although the disease is highly harmful, a difficult situation exists. Currently, there is no targeted therapy approved by the FDA globally. The existing treatment methods can only relieve the symptoms, and there is an extreme lack of high-quality clinical evidence. The clinical demand is extremely urgent.

It is precisely in this gap that KYV-101 has achieved a breakthrough first and become the world's first CAR-T therapy for autoimmune diseases to submit a BLA.

The Breakthrough of CAR-T

The breakthrough of KYV-101 lies in its mechanism advantages.

As a fully human autologous CD19-targeted CAR-T carrying a CD28 co-stimulatory domain, it is designed to balance efficacy and tolerance, and is mainly used for B-cell-mediated autoimmune diseases.

Multiple clinical studies have proven that KYV-101 has outstanding central nervous system penetration ability and can directly act on the central nervous system. In patients with SPS, KYV-101 can effectively reset the B-cell subsets and upregulate the level of regulatory T cells, thereby improving autoimmune disorders at the root.

In April 2026, Kyverna announced the main analysis results of the KYSA-8 registration study, which are relatively convincing.

Specifically, after a single dose, patients achieved rapid, statistically significant, and clinically meaningful improvements in all primary and secondary endpoints at week 16. Most patients showed significant functional recovery, and all subjects discontinued long-term immunosuppressive therapy.

At week 16, the median improvement in the T25FW was 46%, and 81% of patients achieved a clinical benefit of ≥20%; 31% of patients could complete the T25FW test within 5 seconds, reaching the level of healthy individuals. During the follow-up period, 100% of the 26 patients did not use any SPS-related immunomodulatory drugs again.

The safety performance was also remarkable, with excellent overall tolerance. The adverse reactions were mainly grade 1 - 2 CRS (92%) and grade 1 ICANS (12%), with no severe immune-related toxicity; only 4 cases had grade 3/4 neutropenia, which is a common and controllable adverse reaction of CAR-T; all 3 treatment-related serious adverse events had completely resolved.

Therefore, Kyverna is attempting to pass the FDA review.

The Beginning of a New Era

Although KYV-101 has currently achieved a single-point breakthrough only in Stiff Person Syndrome, its landmark action of submitting a BLA has undoubtedly sounded the clarion call for CAR-T to enter a new era of autoimmune diseases.

The disorder of humoral immunity mediated by B cells is the core pathogenic root of most autoimmune diseases. Abnormal activation of autoreactive B cells leads to the massive production of autoantibodies and immune complexes, which then attack multiple tissues and organs throughout the body. Therefore, achieving precise B-cell depletion through CAR-T and blocking antibody production at the source has the underlying logic for broad-spectrum treatment of autoimmune diseases.

Mature targets such as CD19, CD20, and BCMA have become the mainstream directions for global pharmaceutical companies to deploy CAR-T for autoimmune diseases, and KYV-101 has also seized the opportunity in this track.

As a broad-spectrum B-cell depletion CAR-T, KYV-101's deployment is not limited to SPS. It has now expanded to multiple major autoimmune indications such as generalized myasthenia gravis, progressive multiple sclerosis, rheumatoid arthritis, lupus nephritis, and systemic sclerosis, with strong pipeline extensibility.

In the second half of 2026, KYV-101 will face intensive clinical catalysts: the one-year follow-up data of KYSA-8 will verify its long-term efficacy; the long-term data of the registration trial in the field of myasthenia gravis and the phase I expansion data of progressive multiple sclerosis will also be announced successively.

If the subsequent results continue to be positive, it will further open up the market's imagination space and push up the overall valuation of the CAR-T autoimmune track in the industry.

It can be predicted that with the emergence of more clinical evidence, the new era of CAR-T treatment for autoimmune diseases is accelerating towards us.

This article is from the WeChat official account "Amino Observation," written by Amino Jun, and is published by 36Kr with permission.