New York, Jan 12, 2026, 09:54 EST — Regular session
- Atara shares plunged roughly 56% following the FDA’s refusal to greenlight EBVALLO (tabelecleucel) in the U.S.
- Regulators have moved beyond manufacturing concerns but remain skeptical whether the ALLELE study sufficiently demonstrates effectiveness for accelerated approval.
- Partner Pierre Fabre and Atara are lining up fast-track discussions with the FDA amid tightening cash flows.
Atara Biotherapeutics shares plunged about 56% to $6.03 in early trading after the U.S. Food and Drug Administration rejected its cell therapy tabelecleucel, marketed as EBVALLO in Europe, for a rare post-transplant cancer. The stock was volatile, swinging between $4.77 and $15.40 as investors reacted to the news, with volume exceeding 1.4 million shares. 1
The company said the FDA’s complete response letter — the agency’s formal notice that an application cannot be approved as submitted — came after the Jan. 9 market close. It confirmed previous Good Manufacturing Practice (GMP) issues had been resolved, with no new safety concerns flagged. However, the letter ruled the single-arm ALLELE trial, lacking a control group, no longer suffices as evidence for “accelerated approval,” a pathway that allows conditional clearance pending later studies. Atara said Pierre Fabre’s U.S. arm intends to seek a Type A meeting — an expedited FDA session for stalled developments — expected within 45 days. The company also reported about $8.5 million in cash and equivalents as of Dec. 31 and revealed a recent reduction in the U.S.-approval milestone in its Pierre Fabre deal to $31 million, plus an additional $15 million tied to a later commercial goal. “We are surprised and disappointed,” CEO Cokey Nguyen said. 2
Pierre Fabre said the FDA’s latest letter demands a new study, despite earlier agreement on the resubmission and acknowledgment that the previous GMP issue was resolved. The French company warned the decision could have “far-reaching consequences” for ultra-rare disease development. It added it will continue working with Atara to push for accelerated approval while maintaining an expanded access program for patients. 3
For investors, the crucial change is the FDA’s focus shifting from manufacturing concerns to evidence. A year back, the debate centered on whether the product could meet specifications. Today, the issue is whether the agency will even accept the current efficacy data.
That drags timelines right back into question. Should regulators demand a new study, it could take months simply to settle on endpoints and design—then even longer to conduct it within a small, tough-to-enroll transplant group.
Atara’s revealed cash figure only adds to the strain. Although it has shifted much of the tab-cel workload and expenses to Pierre Fabre, investors remain alert for any hints of fresh funding, restructuring, or strategic shifts should regulatory delays persist.
One key focus remains the “Type A” meeting. These sessions often break stalemates quickly, yet they can also solidify negative signals — a blunt “you need new data” warning — which dampens hopes for any immediate gains.
The downside is clear. A new study request usually means extra costs and delays. For a small-cap biotech, that often spells dilution risk or a rush to find partners if funding dries up.
Next on the agenda is the FDA meeting process. Traders want a date for the Type A meeting and, crucially, whether Pierre Fabre and Atara can convince the agency to maintain the accelerated-approval pathway—or if the whole program will have to reboot with a new trial strategy.
