FDA to reconsider shock rejection of cell therapy Ebvallo. Could uniQure be next?

After a surprise rejection at the beginning of 2026, the FDA has agreed to reconsider a T-cell therapy based on the same single-arm trial that the agency had previously found problematic.

For Pierre Fabre Pharmaceuticals and Atara Biotherapeutics’ Ebvallo, the FDA agreed during a recent meeting that a single-arm study using an appropriate historical control “could serve as an adequate and well-controlled study” in support of an application for approval, the two companies said Thursday.

Pierre Fabre and Atara are aiming to get Ebvallo, also known as tabelecleucel or tab-cel, approved for patients with relapsed or refractory Epstein-Barr virus-positive post-transplant lymphoproliferative disease (EBV+PTLD) who have failed on an anti-CD20 regimen. Before the FDA, European regulators had already greenlighted the immunotherapy for the indication in 2022.

Back when the FDA declined to approve Ebvallo in January, the agency said that the same single-arm trial the pair conducted was “not an adequate and well-controlled study,” with myriad deficiencies that rendered its results uninterpretable. At the time, Atara called the FDA’s surprise ruling “a complete reversal of position” that ran “contrary to” the FDA’s previous communications and alignment with the company.

Now, instead of running a separate trial, the two companies plan to resubmit Ebvallo with additional patients and a longer follow-up of the single-arm study, called Allele. 

“We thank the FDA review team for a productive discussion on the tabelecleucel BLA and look forward to finalizing the resubmission plan with the agency in the coming weeks,” Adriana Herrera, CEO of Pierre Fabre’s U.S. subsidiary, said in a May 7 statement. “U.S. patients living with this ultra-rare form of lymphoma urgently need an FDA-approved treatment option as none currently exist, and the lifespan of individuals with R/R EBV+ PTLD is often measured in weeks to months following failure of standard treatment.”

EBV+ PTLD is an ultra-rare and highly aggressive blood cancer that occurs when B-cells proliferate uncontrollably due to EBV reactivation in patients who have received immunosuppressants for a stem cell or solid organ transplant. Only a few hundred patients are impacted by EBV+ PTLD every year.

Ebvallo is an off-the-shelf immunotherapy consisting of EBV-specific cytotoxic T cells derived from healthy EBV-seropositive donors with the goal of eliminating EBV-expressing cells.

As a cell therapy, Ebvallo is regulated by the FDA’s Center for Biologics Evaluation and Research (CBER). Vinay Prasad, M.D., a hematologist who oversaw the FDA department at the time of Ebvallo’s January rejection, left the agency at the end of April.

Ebvallo was one of multiple rare disease candidates to stumble at the FDA, as the agency took issue with several single-arm, natural history studies—even as Commissioner Marty Makary, M.D., touted regulatory flexibility for orphan drugs. 

One of the most high-profile cases is the FDA’s refusal of uniQure’s single-arm trial, compared to natural history data, as basis for an application for its Huntington’s disease gene therapy, AMT-130, which also falls under CBER. As uniQure alleges an about-face, the FDA insists that a randomized, sham-controlled phase 3 trial has always been the agency’s recommendation. 

UniQure is up for its own meeting with the FDA following a very public dispute. And the Ebvallo case could reignite investors’ hope of a potential reversal for AMT-130, too.
 

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During the company’s first-quarter earnings call on Tuesday, uniQure’s chief medical officer, Walid Abi-Saab, M.D., described the upcoming FDA conversation as a “technical meeting” rather than a reassessment of the agency’s stance.

“Our hope is to gain some clarity on key design elements of an additional new study to evaluate the efficacy of AMT-130 and also to get feedback on the statistical analysis plan for the four-year data,” Abi-Saab said on the call, later adding that, “We do not intend to have specific discussion about a regulatory path to file filing at this point. ”

Nevertheless, Leerink Partners analysts see the meeting as “an opportunity for the FDA to evolve its stance” if uniQure generates compelling four-year data. 

UniQure will meet with the FDA this quarter and plans to report four-year results from AMT-130’s existing clinical trial in the third quarter.