FDA Expands Casgevy Approval to Children as Young as 2 Years With Sickle Cell Disease or Transfusion-Dependent β-Thalassemia

The FDA has granted supplemental approval to exagamglogene autotemcel (Casgevy; Vertex Pharmaceuticals) for patients 2 years and older with sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) or transfusion-dependent β-thalassemia (TDT), marking the first gene therapy approved for children as young as 2 years with SCD.¹

Previously, casgevy was approved for patients at 12 years of age and older with SCD with recurrent VOCs or TDT.¹ This expansion broadens access to a one-time, autologous CRISPR/Cas9 genome-edited cell therapy for younger pediatric patients with serious inherited blood disorders.

Burden of Disease

SCD is an inherited red blood cell disorder characterized by abnormal hemoglobin, which can cause red blood cells to become rigid and sickle-shaped.² These cells may obstruct blood flow, leading to VOCs, severe pain, organ damage, and other complications. Pain crises are among the most common complications of SCD and are a leading reason for emergency department visits and hospitalizations among affected patients.²

Transfusion-dependent β-thalassemia is an inherited blood disorder characterized by reduced or absent β-globin production, which leads to ineffective red blood cell production, chronic anemia, and reduced oxygen delivery to tissues.³ Patients with TDT often require regular red blood cell transfusions to maintain adequate hemoglobin levels, which can contribute to long-term treatment burden and transfusion-related complications.¹

How Casgevy Works

Casgevy’s composition consists of the patient’s own hematopoietic stem cells that are collected, edited ex vivo using CRISPR/Cas9 technology, and then infused back into the patient as a one-time intravenous dose.¹ The edited cells engraft in the bone marrow after myeloablative conditioning, allowing the body to produce higher levels of fetal hemoglobin (HbF).^1,3

In patients with SCD, increased HbF helps prevent red blood cells from sickling, thereby addressing the underlying driver of VOCs.¹ In patients with TDT, increased HbF and total hemoglobin levels can reduce or eliminate dependence on regular red blood cell transfusions.¹

Casgevy requires full myeloablative conditioning before infusion, causing treatment to involve intensive preparation and monitoring similar to other hematopoietic stem cell transplant–based approaches.¹

Pediatric Efficacy Data

The FDA evaluated the safety and efficacy of Casgevy in patients aged 5 years to younger than 12 years with SCD in a clinical trial that included 11 patients. Among the 8 patients who were evaluable for efficacy, all achieved the primary efficacy outcome of VF12, defined as no protocol-defined severe VOCs for at least 12 consecutive months within the first 24 months after infusion.¹

For patients 5 years of age to younger than 12 years with TDT, efficacy and safety were evaluated in a trial of 15 patients. Among 9 patients evaluable for efficacy, 8 achieved transfusion independence for 12 consecutive months, with a median duration of transfusion independence of 20.1 months.¹

The indication was expanded to children 2 years of age and older based on the therapy’s product characteristics and available pediatric clinical trial data.¹

Safety Considerations

The most common adverse reactions reported with Casgevy were mucositis and febrile neutropenia in patients with SCD and TDT, as well as decreased appetite in patients with SCD.¹ The prescribing information includes warnings for neutrophil engraftment failure, delayed platelet engraftment, hypersensitivity reactions, and potential off-target genome editing risk.^1,3

These safety considerations reinforce the need for careful supportive care before and after infusion. Healthcare workers may play a larger role in chemotherapy-related supportive care, antimicrobial prophylaxis, management of mucositis and febrile neutropenia, transfusion support coordination, medication reconciliation, and patient and caregiver counseling.

Implications for Pharmacists

The expanded approval of Casgevy represents a significant shift in the treatment landscape for pediatric SCD and TDT, particularly because earlier intervention may reduce cumulative disease burden and long-term complications. Pharmacists involved in hematology, pediatrics, specialty pharmacy, transplant, and managed care settings may be increasingly involved in identifying treatment considerations, educating families, coordinating access, and supporting safe administration pathways.

The approval was granted 53 days after filing and was the eighth approval selected for the FDA Commissioner’s National Priority Voucher pilot program. Casgevy also received orphan drug, regenerative medicine advanced therapy, and fast track designations.¹

REFERENCES

1. FDA. FDA approves first gene therapy for young children with sickle cell disease. Published July 1, 2026. Accessed July 6, 2026. https://www.fda.gov/news-events/press-announcements/fda-approves-first-gene-therapy-young-children-sickle-cell-disease?utm_medium=email&utm_source=govdelivery

2. CDC. Complications of sickle cell disease: pain. Updated May 15, 2024. Accessed July 6, 2026. https://www.cdc.gov/sickle-cell/complications/pain.html

3. FDA. Casgevy. Updated July 2, 2026. Accessed July 6, 2026. https://www.fda.gov/vaccines-blood-biologics/casgevy