Vertex/CRISPR Partnered Cell Therapy Shows Encouraging Response In Sickle Cell Disease, Thalassemia Patients

Vertex Pharmaceuticals Incorporated VRTX and CRISPR Therapeutics AG CRSP announced that pivotal trials for exagamglogene autotemcel (exa-cel) for transfusion-dependent beta-thalassemia (TDT) or severe sickle cell disease (SCD) met primary and key secondary endpoints at pre-specified interim analyses. 

Of the 48 patients with TDT who had received exa-cel at the time of the analysis, 24/27 (88.9%) achieved the primary endpoint of transfusion independence for at least 12 consecutive months (TI12) and the secondary endpoint of transfusion independence for at least 6 consecutive months (TI6) with mean weighted hemoglobin of at least 9 g/dL.

The mean duration of transfusion independence was 20.5 months, with a maximum of 40.7 months.

The mean proportion of edited BCL11A alleles was stable in the bone marrow and peripheral blood over time, indicating successful permanent editing in long-term hematopoietic stem cells.

Of the 35 patients with SCD who had received exa-cel at the time of the analysis, 16/17 (94.1%) achieved the primary endpoint of freedom from vaso-occlusive crises (VOCs) for at least 12 consecutive months (VF12).

The mean duration of VOC-free was 18.7 months, with a maximum of 36.5 months. 17/17 (100%) achieved the key secondary endpoint of being free from VOC-related hospitalizations for at least 12 consecutive months.

In the analysis of all patients who received exa-cel, mean fetal hemoglobin was more than 30% of total hemoglobin by Month 3 and was then maintained at approximately 40.0%.

The FDA has accepted the application for exa-cel for sickle cell disease and transfusion-dependent beta-thalassemia (TDT). 

The FDA has granted priority review for exa-cel in SCD with a PDUFA date of December 8, 2023, and standard review for TDT with a PDUFA date of March 30, 2024.

Price Action: VRTX shares are up 0.61% at $334.39, and CRSP shares are down 1.79% at $61.47 on the last check Friday.