Kyverna touts year-long miv-cel data as Novartis, Bristol Myers pause autoimmune CAR-T trials

Overview

Updated Sep 24

Novartis paused its autoimmune CAR-T trials this month after three patients died from a severe immune reaction, and Bristol Myers paused its own over similar inflammatory events. The same week, Kyverna Therapeutics released 12 months of follow-up data on miv-cel, its rival therapy, reporting sustained improvement in stiff person syndrome patients with no high-grade immune toxicity.

Kyverna is closest to market with an autoimmune CAR-T. It has begun filing for FDA approval in stiff person syndrome and aims to complete the application in the fourth quarter of 2026, putting a potential launch in 2027 — which would make it the first chimeric antigen receptor T-cell therapy cleared for a disease outside cancer.

Why it matters

The first CAR-T approved for an autoimmune disease sets the safety and dosing standard every rival must match, and the biggest players just stumbled.

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Key Indicators

Deaths in Novartis's paused autoimmune CAR-T trials

Participants died from IEC-HS, a severe immune overreaction that damaged organs.

100+

Patients treated with miv-cel across trials

Kyverna reports no high-grade CRS, ICANS, or IEC-HS in this population.

46%

Median gait-speed improvement at week 16 (KYSA-8)

Stiff person syndrome patients improved on a timed 25-foot walk test after a single dose.

98%

miv-cel manufacturing success rate

Kyverna uses a conventional validated process rather than the faster methods of paused rivals.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Warner Biddle

President and chief executive, Kyverna Therapeutics

Leading miv-cel's FDA filing and launch preparations

Organizations Involved

Kyverna Therapeutics

Biotech company

Filing for FDA approval of miv-cel in stiff person syndrome

Emeryville, California biotech developing miv-cel, an anti-CD19 cell therapy, for autoimmune diseases.

Novartis Pharmaceuticals

Pharmaceutical company

Paused three autoimmune CAR-T trials after participant deaths

Swiss drugmaker that developed the first approved CAR-T, Kymriah, and was applying the platform to autoimmune disease.

Bristol Myers Squibb

Pharmaceutical company

Paused autoimmune CAR-T trials over reversible inflammatory events

US drugmaker with two approved CAR-T therapies, Breyanzi and Abecma, also testing the platform in autoimmune disease.

U.S. Food and Drug Administration

Federal regulator

Reviewing Kyverna's rolling application; agreed on KYSA-8 primary endpoint

US agency that approves new drugs and biologics; will decide whether miv-cel is the first autoimmune CAR-T.

Timeline

February 2024 September 2026

6 events Latest: September 24th, 2026 · 2 months ago

Tap a bar to jump to that date

September 2026
Kyverna reports year-long miv-cel data as rivals stumble
Latest Clinical Data

Sustained benefit with no high-grade CRS, ICANS, or IEC-HS across more than 100 patients.
September 24th, 2026
Kyverna begins rolling FDA application for miv-cel
Regulatory

At FDA request, Kyverna started submitting its biologics license application for stiff person syndrome.
September 15th, 2026
Novartis and Bristol Myers pause autoimmune CAR-T trials
Safety

Novartis halted trials after three deaths from IEC-HS; Bristol Myers paused over reversible inflammatory events.
September 1st, 2026
April 2026
Kyverna presents stiff person syndrome baseline data at AAN
Clinical Data

Natural history study showed most SPS patients see no meaningful improvement over 10 years without miv-cel.
April 15th, 2026
Kyverna reports 52-week myasthenia gravis data at AAN
Clinical Data

Phase 2 results showed 100% of patients responding, with durable benefit and no high-grade immune events.
April 15th, 2026
February 2024
Kyverna prices IPO on Nasdaq
IPO

Kyverna went public, raising about $319 million to fund miv-cel's clinical development.
February 5th, 2024

Scenarios

FDA approves miv-cel as first autoimmune CAR-T

Likely Resolves by End of 2027

Discussed by: Kyverna leadership; analysts at TD Cowen, William Blair, and Fierce Biotech coverage

Kyverna completes the biologics license application in the fourth quarter of 2026 with the year-long follow-up data and the additional natural history analysis the FDA requested. The agency reviews the filing on a standard timeline, issuing an approval for stiff person syndrome during 2027. That would make miv-cel the first CAR-T cleared for any disease outside cancer.

Novartis and Bristol Myers resume paused autoimmune CAR-T trials

Possible Resolves by Q2 2027

Discussed by: William Blair analyst Sami Corwin; analysts citing improved IEC-HS recognition and management

The paused companies redesign trial protocols, tighten patient selection, or adjust their manufacturing methods, then resume enrollment. Corwin has said greater physician awareness of IEC-HS symptoms will improve outcomes over time, which supports a path back to the clinic. Resumption would signal the safety events were manageable rather than class-ending for the rapid-manufacturing approach.

miv-cel clears its gMG Phase 3 and expands beyond stiff person syndrome

Possible Resolves by End of 2028

Discussed by: Kyverna leadership; Morgan Stanley and Wells Fargo conference coverage

The KYSA-6 registrational trial in generalized myasthenia gravis, amended into a Phase 2/3 design aligned with the FDA, completes Phase 3 enrollment and hits its co-primary endpoints. That broadens miv-cel from a rare-disease product into a larger neuromuscular market and validates the cancer-to-autoimmune bridge across multiple indications.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

March 2006

TGN1412 trial disaster (2006)

In a London phase 1 trial, six healthy volunteers received an anti-CD28 antibody and within hours went into multiple organ failure from a cytokine storm; two were left critically ill. The trial was halted as the drug overactivated immune cells far beyond expectations.

Then

Regulators worldwide tightened requirements for first-in-human trials of immune-modulating drugs, including staggered dosing and closer monitoring.

Now

The event became a permanent cautionary tale for any therapy that broadly activates the immune system, shaping risk assessment for the entire biologics field.

Why this matters now

Novartis's IEC-HS deaths are the same failure mode in a new context: a single severe immune reaction freezing clinical development. Kyverna's clean safety record is the counterargument that the mechanism, not the drug class, determines risk.

August 2017

Kymriah, first CAR-T approval (2017)

Novartis won FDA approval of tisagenlecleucel, marketed as Kymriah, for pediatric acute lymphoblastic leukemia. It was the first gene-therapy cell treatment approved anywhere, establishing CAR-T as a viable modality.

Then

Kymriah and later CAR-T products created a multibillion-dollar cancer treatment category while managing well-documented cytokine release syndrome and neurotoxicity risks.

Now

Novartis retained a leading position in cell therapy, which it was extending into autoimmune disease when its latest trials were paused.

Why this matters now

The company that defined the first CAR-T wave is now stumbling in the second wave. That opens the door for a smaller developer like Kyverna to set the safety and manufacturing norms for autoimmune application.

1997–2006

Rituximab's move from cancer to autoimmune disease (1997–2006)

Rituximab (Rituxan), an antibody that depletes B cells, was approved for lymphoma in 1997 and then for rheumatoid arthritis in 2006, becoming the first targeted therapy to cross from oncology into autoimmune care.

Then

Rituximab became a standard rheumatoid arthritis treatment and spawned a class of B-cell-depleting drugs.

Now

It established the cancer-to-autoimmune bridge that CAR-T developers, including Kyverna, are now following with engineered cell therapies instead of repeat antibody infusions.

Why this matters now

miv-cel is pursuing the same expansion rituximab pioneered, but as a one-time treatment. Its success would prove cell therapy can do what antibody drugs already did — rewire the immune system across disease categories.