FDA Approves Omisirge for Severe Aplastic Anemia: A New Option for Patients Without a Suitable Donor

The FDA has approved Omisirge (omidubicel-onlv) for adults and children 6 years and older with severe aplastic anemia (SAA) who are eligible for allogeneic hematopoietic stem cell transplantation (HSCT) but do not have a compatible donor. This approval makes Omisirge the first HSCT therapy authorized for this patient population, offering a new route to transplantation for people who otherwise have limited options.

Omisirge, developed by Gamida Cell and now part of Ayrmid, is an expanded and cryopreserved allogeneic cell therapy derived from umbilical cord blood and processed using a nicotinamide-based platform. The technology increases the number and functionality of hematopoietic progenitor cells, supporting faster and more reliable engraftment.

This is the therapy’s second FDA-authorized indication. Omisirge was previously approved for adults and adolescents 12 years and older with hematologic malignancies, where it demonstrated faster neutrophil recovery and fewer early infectious complications compared to conventional umbilical cord blood transplant.

Basis for Approval: Ongoing Open-Label Study in SAA

The SAA approval is supported by an ongoing, open-label, prospective, single-center Phase 1/2 study (NCT03173937) led by the National Heart, Lung, and Blood Institute (NHLBI). The study enrolled patients who required transplantation but lacked a suitably matched donor.

Key findings include:

Rapid neutrophil recovery

Median recovery occurred at 11 days, substantially earlier than typical expectations in alternative-donor transplantation for SAA.

Early and sustained engraftment

86 percent of patients showed durable neutrophil recovery at 100 days.

Transfusion independence

86 percent of participants achieved red blood cell transfusion independence.

Strong survival outcomes

Disease-free and overall survival was approximately 92 percent in early reports. Later updates presented at ASH 2025 reported disease-free and overall survival reaching 94 percent in expanded cohorts.

Although the study is single-arm, the observed engraftment kinetics, transfusion independence, and survival outcomes represent a meaningful advance for patients who traditionally face high transplant-related risks due to donor unavailability.

Safety Profile

The FDA noted that the safety profile of Omisirge is consistent with what is expected after allogeneic HSCT. In the SAA study, common adverse events included:

• Febrile neutropenia
• Viral and bacterial infections
• Hyperglycemia
• Immune thrombocytopenia
• Pneumonia

Omisirge also carries boxed warnings for graft-versus-host disease (GVHD), engraftment syndrome, graft failure, and infusion reactions. Autoimmune cytopenias were observed in about one-quarter of treated patients. No cases of severe acute or chronic GVHD were reported in the SAA cohort.

 Expert Perspectives

Dr. Vinay Prasad, Director of CBER’s Office of Therapeutic Products, described the approval as an important advance for people with severe aplastic anemia who cannot access a compatible donor. He emphasized the agency’s commitment to expanding treatment pathways for rare and life-threatening blood disorders.

Dr. Richard Childs, principal investigator at the NHLBI, highlighted the therapy’s ability to achieve rapid engraftment with high survival rates and low GVHD in a population that historically faces major transplant barriers.

From an industry standpoint, Dr. Joe Wiley, CEO and Chairman of Ayrmid, noted that Omisirge may help transform treatment for SAA patients who previously had few viable transplant options. He also reiterated the company’s long-term commitment to expanding availability of cell therapies for underserved hematologic conditions.

Manufacturing and Commercial Expansion

To support wider access, Ayrmid has partnered with RoslinCT, a cell therapy contract development and manufacturing organization. Technology transfer to RoslinCT’s facility in Hopkinton, Massachusetts, is underway, with commercial manufacturing expected to begin in 2027. This domestic expansion is intended to ensure scalability, supply stability, and broader distribution across the United States.

A New Era for Transplant Options in SAA

The approval of Omisirge introduces a therapeutic option for SAA patients who cannot identify a matched donor. Its ability to promote fast and sustained engraftment, along with encouraging early survival outcomes, signals a significant advance in a field that has seen limited innovation. As additional data mature and manufacturing capacity expands, Omisirge has the potential to reshape HSCT access for people with severe aplastic anemia and related conditions.