Vertex Pharmaceuticals Incorporated (NASDAQ:VRTX) on Saturday presented data from multiple studies demonstrating the clinical benefits of Casgevy (exagamglogene autotemcel) in patients aged 5 years and older with severe sickle cell disease (SCD) or transfusion-dependent beta thalassemia (TDT).
SCD is a severe inherited blood disease that damages red blood cells, limits oxygen delivery, causes intense pain, and can shorten life.
TDT is a life-threatening genetic condition that forces patients to rely on regular blood transfusions and lifelong treatment to remove excess iron.
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The data were presented at the 2025 American Society of Hematology (ASH) Annual Meeting.
First presentation of data in children ages 5-11 years treated with Casgevy
In children with SCD, 11 patients have been dosed with Casgevy in the Phase 3 CLIMB-151 clinical study, and all (4/4) patients with sufficient follow-up achieved the primary endpoint of being free from vaso-occlusive crises (VOCs) for at least 12 consecutive months (VF12).
VOC is a painful episode caused by rigid, sickled red blood cells blocking small blood vessels.
- No patient experienced a VOC following infusion with CASGEVY, with the longest duration of VOC-free of approximately two years.
In children with TDT, 13 patients have been dosed with Casgevy in the Phase 3 CLIMB-141 clinical study, and all (6/6) patients with sufficient follow-up achieved the primary endpoint of transfusion independence for at least 12 consecutive months while maintaining a weighted average hemoglobin (Hb) of at least 9 g/dL (TI12).
- Following Casgevy infusion, 12/13 are transfusion-free, with the longest duration of transfusion-free just under two years.
- One patient died from pneumonia in the setting of multi-organ failure due to severe veno-occlusive disease related to the busulfan conditioning.
The safety profile of Casgevy in younger patients is consistent with myeloablative conditioning and autologous transplant in both SCD and TDT, as established in clinical studies in older patients.
Consistent with studies in older patients, children treated with Casgevy have durable increases in fetal hemoglobin (HbF) and stable allelic editing.
“These results, the first clinical data ever presented on any genetic therapy for children ages 5-11 years with SCD, again demonstrate the transformative potential of CASGEVY,” said Carmen Bozic, M.D., Executive Vice President, Global Medicines Development and Medical Affairs, and Chief Medical Officer at Vertex.
The company presented new, longer-term data in SCD and TDT patients ages 12 years and older from the pivotal clinical studies of Casgevy at the ASH meeting.
These data, as of April 2025, continue to demonstrate the durable clinical benefits.
In SCD, 100% of patients (45/45) achieved VF12 in either CLIMB-121 or the long-term follow-up study CLIMB-131, with a mean duration of VOC-free for 35.3 months.
In TDT, 98.2% (55/56) achieved TI12 in either CLIMB-111 or CLIMB-131 with a mean duration of transfusion independence of 41.4 months.
VRTX Price Action: Vertex Pharmaceuticals shares were up 0.22% at $456.50 during premarket trading on Monday, according to Benzinga Pro data.
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