Kyverna Therapeutics has officially started a rolling Biologics License Application submission to the FDA for miv-cel, keeping the candidate on track to be the first autoimmune CAR-T to reach the market.
The filing comes after the agency agreed with the company’s plan during a recent meeting, confirming that data from the single-arm KYSA-8 trial will be sufficient to support an application in stiff person syndrome, Kyverna said Tuesday alongside its first-quarter earnings report.
Kyverna is seeking priority review under its Regenerative Medicine Advanced Therapy (RMAT) designation and anticipates completing the filing by the fourth quarter of 2026.
By reaching alignment with the FDA, Kyverna has effectively removed a potential regulatory overhang that has shadowed the sector since the agency pushed back on uniQure’s Huntington’s disease gene therapy program over a single-arm trial compared to natural history data.
Still, Kyverna doesn’t have the full package just yet as the FDA has made a request for more information.
At the agency’s request, Kyverna will include additional analysis of its natural history study, which was recently presented at the 2026 American Academy of Neurology annual meeting. Besides, while the agency has agreed on KYSA-8’s primary endpoint based on a timed 25-foot walk test (T25FW) at 16 weeks, Kyverna will also submit data from a one-year follow-up, which is expected in the second half of 2026.
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The natural history study, the largest for SPS and enrolling 153 patients, “supports and contextualizes the transformative impact” miv-cel has shown in KYSA-8, Kyverna CEO Warner Biddle said Tuesday in an interview with Fierce.
Kyverna is still working with the agency to finalize the exact assessment required, but Biddle said the company doesn’t need to generate new data and instead merely needs to conduct additional analysis using existing data points. The agency did not raise any questions about the methodology used in the natural history data set, Biddle said.
The natural history study found no or minimal improvement for the majority of SPS patients over a 10-year period despite existing off-label treatment options, according to results shared at AAN. By comparison, in KYSA-8, miv-cel helped 26 patients achieve a median 46% improvement compared with baseline on T25FW at week 16. Of the 12 patients who required a walking aid at baseline, eight (67%) no longer needed assistance by week 16.
The FDA has seen the results presented at AAN and is asking for an additional analysis “that will help them understand and put the KYSA-8 study into perspective,” Biddle said.
As for the longer-term data, Kyverna already has some results for certain KYSA-8 patients beyond the 16-week mark. Now, the rolling submission allows the company to add more data covering all 26 patients out to one year, Biddle said.
“We believe this increases the confidence in the filing even further,” he added. “And it will support us from a labeling perspective in an eventual commercialization once we get to that point.”
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Kyverna is filing miv-cel—full name mivocabtagene autoleucel—after Vinay Prasad, M.D., the FDA’s controversial former director of the Center for Biologics Evaluation and Research overseeing cell and gene therapy, left the agency at the end of April. Katherine Szarama, Ph.D., has taken over in an acting capacity.
The leadership transition seemingly has not affected Kyverna’s case.
“We’ve seen a lot of consistency with the review team, and we don’t anticipate these changes are going to change our projected timelines,” Biddle said. “In fact, the conversations we’ve been having […] with the FDA have been very collaborative and supportive. And there’s a mutually aligned perspective on stiff person syndrome being that there’s no approved therapies, and there’s really an urgent need to bring these new therapies to patients as quickly as possible.”
In anticipation of the potential launch, Kyverna recently hired Omeros and AbbVie alum Nadia Dac as its chief commercial officer.
