The FDA has delayed its target decision date for Orca Bio’s blood cancer cell therapy candidate Orca-T by three months to July 6.
The review extension comes after the company submitted additional data related to chemistry, manufacturing and controls (CMC) a couple of weeks ago upon request by the agency, Orca Bio’s CEO Nate Fernhoff, Ph.D., told Fierce.
Fernhoff wouldn’t specify the exact nature of the FDA’s questions but said the company doesn’t believe “any of these to be fundamental or unaddressable.”
The delay comes at a time when the biopharma industry is highly attuned to FDA actions on cell and gene therapies after a string of regulatory surprises that has culminated in the planned departure of Vinay Prasad, M.D., director of the FDA’s Center for Biologics Evaluation and Research (CBER).
The FDA in July declined to approve Replimune’s oncolytic immunotherapy RP1 for the treatment of melanoma. As an engineered virus therapy, RP1 falls within the purview of CBER. However, the decision to reject RP1 was reportedly sought by Richard Pazdur, M.D., who was then director of the FDA’s Oncology Center of Excellence, rather than CBER, according to Stat.
The FDA has since accepted Replimune’s resubmission, with a decision expected by April 10, and Pazdur has left the FDA after an internal disagreement over a new policy proposal on clinical trials.
Fernhoff confirmed that Orca Bio’s ongoing CMC-related interactions with the FDA are with CBER.
The nature of the FDA’s concern is about “the CMC and the control of drug product and making sure that fully meets the regulatory standard,” he said.
The questions are not about clinical data or Orca-T’s treatment effect, Fernhoff stressed.
Orca Bio’s Orca-T is an engineered allogeneic cell therapy designed to improve blood cancer patients’ tolerance to transplant treatments. It leverages hematopoietic stem cells and regulatory T (Treg) cells, followed by conventional T cells, whereas a regular stem cell transplant contains a mix of various cell types, including some that may cause graft-versus-host disease (GVHD).
In the phase 3 Precision-T trial, a group of patients with various blood cancers experienced a one-year chronic GVHD-free survival rate of 78%, significantly better than the 38.4% rate saw in patients who received traditional allogeneic stem cell transplants.
On a composite endpoint measuring patients who remained free from both GVHD and cancer relapse, the Orca-T group had significantly better outcomes, with a 63% rate at one year versus 31% in the control group.
While the trial was positive, questions could be raised about the design of the control arm, in which patients received the standard tacrolimus/methotrexate combination for preventing GVHD. However, after Precision-T was launched, a cyclophosphamide-based regimen has emerged as a better post-transplant GVHD prophylaxis option.
The control arm of the phase 3 trial recruited patients entirely within the U.S., meeting the gold standard for clinical experiments, Fernhoff argued. Again, as the Orca Bio CEO emphasized, the FDA extension is not about clinical efficacy data.
As the delay has disrupted Orca Bio’s commercial plan, the California biotech is working with the FDA to launch an expanded access program to offer Orca-T ad interim to patients before a potential approval, Fernhoff said.
At the beginning of 2026, Orca Bio announced a series F financing round completed in December 2025 to support Orca-T launch readiness and pipeline advancements.
Fernhoff declined to comment on the potential impact of the upcoming CBER leadership change on the Orca-T review, but he cited frequent engagement with the FDA review team, touting multiple interactions and “a good dialogue along the way.”
The field of cell therapy for cancer has encountered many CMC-related challenges, including back-and-forth discussions between drugmakers and the FDA related to product specifications and potency. Thankfully for Orca Bio, potency doesn’t seem to be a lingering issue for Orca-T.
Even as the FDA saves the topic of product specifications until final label discussions, Fernhoff said he doesn’t expect Orca-T will be subject to the same challenges of potency assay related to mechanism of action. In cell therapy, potency assays are used to measure the biological activity of the therapeutic cells to ensure the strength of the final product. As the FDA noted in an industry guidance (PDF), the “complexity of CGT products can present significant challenge(s) to establishing potency assays.”