FDA Approves Omisirge: New Allogeneic Stem Cell Therapy for Hematologic Cancers

Key Takeaways

• FDA approved Omisirge (omidubicel-onlv) under BLA 125703 on April 17, 2023 for adult and pediatric patients aged 12+.
• Phase 3 trial (NCT02730299) showed median neutrophil recovery in 12 days versus 22 days for standard cord blood (p<0.001).
• Infections through Day 100 were lower with Omisirge (39%) versus unmanipulated cord blood (60%).
• Patients stayed out of hospital a median of 61 days versus 48 days in the first 100 days post-transplant.
• Therapy addresses the unmet need for patients lacking matched sibling or unrelated donors.

  What Is Omisirge and How Does It Work?

  Omisirge is a cellular therapy derived from umbilical cord blood. It uses nicotinamide-based ex vivo expansion to multiply CD34+ hematopoietic stem and progenitor cells. This technology increases the cell dose available for transplantation.

  The expanded cells are infused into patients after myeloablative conditioning. They then migrate to the bone marrow and rebuild the blood and immune systems. Faster engraftment reduces the period of neutropenia when patients are vulnerable to infections.

  When Was Omisirge Approved and What Did the Clinical Trials Show?

  The FDA granted approval on April 17, 2023, following Phase 3 trial results published in the Blood Journal. The study randomized patients to receive either omidubicel or standard unmanipulated cord blood transplantation.

  Key findings included:

  • Neutrophil recovery occurred at a median of 12 days for omidubicel versus 22 days for standard cord blood (95% CI: 10-14 vs 19-25 days; p<0.001)
  • Cumulative incidence of neutrophil engraftment by Day 42 was 96% versus 89% (p<0.001)
  • Platelet recovery by Day 42 was achieved by 55% versus 35% of patients (p=0.028)
  • Bacterial or fungal Grade 3 infections occurred in 39% versus 60% of patients (p=0.027)
  • Median days out of hospital in the first 100 days was 61 versus 48 days (p=0.005)

  Which Patients Benefit from Omisirge?

  Omisirge is indicated for patients aged 12 years and older with hematologic malignancies undergoing myeloablative conditioning prior to umbilical cord blood transplantation. This includes patients with acute leukemias, lymphomas, and myelodysplastic syndromes.

  The primary target population is patients who lack a matched sibling donor or a readily available matched unrelated donor. Cord blood has traditionally been an alternative for these patients, but delayed engraftment has limited its use. Omisirge addresses this limitation by accelerating hematopoietic recovery.

  What Are the Safety Considerations for Omisirge?

  Safety data from the Phase 3 trial showed adverse events consistent with standard allogeneic hematopoietic stem cell transplantation. These included graft-versus-host disease (GVHD), infections due to immunosuppression, and cytopenias requiring transfusions.

  The FDA did not identify unexpected toxicities in its review. Healthcare providers should monitor patients for the same complications associated with traditional stem cell transplantation, including acute and chronic GVHD, organ toxicities, and infectious complications during the neutropenic period.

  How Does Omisirge Compare to Alternative Stem Cell Sources?

  Comparison of stem cell sources for transplantation

  Source	Availability	Time to Neutrophil Recovery	Key Limitation
  Omisirge (omidubicel)	Off-the-shelf cord blood	12 days (median)	Requires specialized manufacturing
  Standard cord blood	Off-the-shelf	22 days (median)	Delayed engraftment, higher infection risk
  Matched sibling donor	Limited to 25-30% of patients	14-18 days (typical)	Requires HLA-matched family member
  Unrelated donor (MUD)	Requires 3-4 month search	14-18 days (typical)	Search delays, donor availability

  What Is the Regulatory History of Omisirge?

  Gamida Cell submitted Biologics License Application 125703 to the FDA. The application included results from Study P0501, the pivotal Phase 3 trial. The FDA reviewed Omisirge under its standard biologics approval pathway with priority considerations for cell therapies addressing unmet needs.

  The approval made Omisirge the first FDA-approved allogeneic stem cell therapy specifically to reduce time to neutrophil recovery in cord blood transplantation. This represents a regulatory milestone for expanded hematopoietic cell products.

  Frequently Asked Questions

  What is Omisirge used for?

  Omisirge (omidubicel-onlv) is approved for use in allogeneic hematopoietic stem cell transplantation to treat hematologic cancers like leukemia and lymphoma, specifically for patients who lack matched sibling donors. It is indicated for patients aged 12 years and older undergoing myeloablative conditioning prior to cord blood transplantation.

  How does Omisirge work?

  Omisirge works by expanding hematopoietic stem and progenitor cells from umbilical cord blood using nicotinamide-based technology, which increases cell dose and improves engraftment speed. The expanded cells are cryopreserved until needed and infused intravenously after conditioning chemotherapy.

  When did the FDA approve Omisirge?

  The FDA approved Omisirge on April 17, 2023, under Biologics License Application (BLA) 125703. The approval was based on Phase 3 clinical trial data showing faster neutrophil recovery compared to standard cord blood transplantation.

  What are the benefits of Omisirge compared to standard cord blood?

  In a Phase 3 trial (NCT02730299), Omisirge patients achieved neutrophil recovery in a median of 12 days versus 22 days for standard cord blood. They also had fewer infections (39% versus 60%), faster platelet recovery (55% versus 35% by Day 42), and spent more days out of hospital in the first 100 days post-transplant (median 61 versus 48 days).

  Primary Sources

  1. U.S. Food and Drug Administration. "Omisirge." Vaccines, Blood & Biologics. Accessed 2026-07-06. FDA product page documenting approval date (April 17, 2023) under BLA 125703.
  2. ClinicalTrials.gov. "A Study to Evaluate the Efficacy and Safety of Omidubicel in Patients Undergoing Umbilical Cord Blood Transplantation." Study ID NCT02730299. Phase 3 randomized trial results.
  3. Blood Journal. "Omidubicel vs standard myeloablative umbilical cord blood transplantation: results of a phase 3 randomized study." Published results showing 12 vs 22 day neutrophil recovery and infection rates.