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Vertex Pharmaceuticals, CRISPR Therapeutics' Gene-Editing Therapy Nabs UK Conditional Authorization

NEW YORK – Vertex Pharmaceuticals and CRISPR Therapeutics on Thursday announced their gene-editing therapy Casgevy (exagamglogene autotemcel) has received conditional marketing authorization from the UK Medicines and Healthcare Products Regulatory Agency (MHRA) as a treatment for sickle cell disease (SCD) and transfusion-dependent beta thalassemia (TDT).

The decision from the UK regulator makes Casgevy the first CRISPR-based treatment to receive marketing authorization in the world, according to the companies. "Today is a historic day in science and medicine," Vertex CEO and President Reshma Kewalramani said in a statement announcing the approval.

Casgevy is indicated as a treatment for SCD patients with recurrent vaso-occlusive crises and who have the βS/βS, βS/β+, or βS/β0 genotype, and for TDT patients. For both indications, patients are eligible if they are at least 12 years old and a human leukocyte antigen-matched related hematopoietic stem cell donor is not available.

Vertex and CRISPR Therapeutics estimate that there are about 2,000 patients in the UK who are eligible for Casgevy, which is designed to reactivate high levels of fetal hemoglobin in red blood cells. Hemoglobin is a protein that carries oxygen and is lacking or dysfunctional in patients with SCD and TDT.

Specifically, Casgevy uses CRISPR-Cas9 to edit patients' own CD34-positive hematopoietic stem and progenitor cells (HSPCs) ex vivo to alter the BCL11A gene and boost fetal hemoglobin levels. Casgevy is intended to be a one-time curative treatment, although additional long-term data are needed to confirm the durability of effectiveness.

In the UK, a conditional marketing authorization is granted for medicines that address a significant unmet need, but comprehensive clinical data are not yet available. Such authorizations are valid for one year, though they can be renewed annually with an ongoing regulatory review of the data.

Once a drug has been approved by the MHRA, it is reviewed by the National Institute for Health and Care Excellence to gauge if it is cost-effective. In the US, the nonprofit Institute for Clinical and Economic Review, which conducts independent value assessments of healthcare interventions, said the therapy could be reasonably priced as high as $2.05 million per infusion.

The gene-editing therapy is also under review by the European Medicines Agency, the Saudi Food and Drug Authority, and the US Food and Drug Administration. The FDA is expected to issue a decision on Vertex's application for the drug in SCD by Dec. 8 and in TDT by March 30, 2024.