The U.S. Food and Drug Administration (FDA) has approved CASGEVYTM (exagamglogene autotemcel), the first CRISPR gene editing therapy to treat patients with transfusion-dependent beta thalassemia (TDT). CASGEVY was developed jointly by Vertex Pharmaceuticals and CRISPR Therapeutics.
Beta thalassemia is an inherited blood disorder that reduces the production of hemoglobin, resulting in severe anemia and other complications. Patients require frequent blood transfusions to manage the disease. The approval provides a revolutionary one-time gene therapy treatment option for these patients.
Highly Effective Treatment Eliminates Need for Transfusions
Clinical trials showed CASGEVY to be highly effective, with over 90% of treated patients becoming transfusion independent. The gene editing therapy works by using CRISPR technology to precisely correct mutations in stem cells taken from the patient’s own blood. The corrected cells are then infused back into the patient where they repopulate the bone marrow and produce normal hemoglobin.
Dr. Haydar Frangoul, Medical Director of Pediatric Hematology and Oncology at Sarah Cannon Research Institute and lead investigator of the clinical trials, said:
“Today’s approval provides a very meaningful treatment option for TDT patients who may no longer have to face a lifetime of chronic transfusion therapy and iron overload. This one-time gene therapy has demonstrated clinically meaningful outcomes with durable transfusion independence, reduced transfusion burden, and improvements in hydroxyurea use.”
Years in the Making, First CRISPR Therapy to Reach Patients
CASGEVY’s journey from conception to reality has spanned over a decade of scientific research. CRISPR gene editing technologies were discovered in the early 2010s and the collaboration between Vertex and CRISPR Therapeutics began in 2015.
“This approval is a culmination of years of work to realize the potential of CRISPR gene editing technologies to treat patients with serious diseases. We are thankful to the patients, families and physicians who helped enable this breakthrough,” said Vertex CEO Reshma Kewalramani.
Phase 1/2 trials published in 2021 first demonstrated the therapy’s ability to eliminate transfusion dependence in the majority of patients. Larger phase 3 trials confirmed the efficacy and safety of CASGEVY over longer follow up, paving the way for today’s approval.
What Comes Next? Expanding Access and Further Innovation
While the $2.9 million price tag for CASGEVY has drawn criticism, Vertex points to the hundreds of thousands of dollars in healthcare costs saved by eliminating the need for chronic transfusions. And this may just be the beginning.
| Phase | Disease | Status |
|---|---|---|
| Phase 1/2 | Sickle Cell Disease | Approved June 2022 |
| Phase 1/2 | Multiple Myeloma | Early trials |
| Preclinical | Other hemoglobinopathies | Research ongoing |
Vertex and CRISPR Therapeutics have already secured a second FDA approval for their CRISPR therapy to treat sickle cell disease last June. They are now exploring the potential to apply the technology to other blood disorders and cancers.
This approval also opens the door for other gene editing therapies – using CRISPR and other methods – paving the way for a new generation of sophisticated genetic medicines.
Concerns Remain Over Long Term Safety
While clinical data so far indicates the treatment is safe, lifelong monitoring is required to watch for potential long term side effects such as unintended DNA changes. Because the genetic correction is permanent and passed onto future generations, ethical concerns have also been raised over the use of germline gene editing.
“There is still much unknown about the short and long term effects of altering human genes,” noted bioethicist Nancy King, “but the approval does represent a shift toward accepting permanent genetic changes as a therapeutic option.”
The therapy’s high cost has also prompted debate over who will have access to these cutting edge treatments. Most patients rely on medical insurance to cover the costs of chronic care for genetic diseases like beta thalassemia. While insurers are likely to cover the one-time gene therapy due to the long term savings, premiums could rise as a result.
Advocacy groups warned the breakthrough could also exacerbate disparities if high costs limit access only to the privileged few.
“This is a major milestone for patients with genetic blood disorders who can now hope for a lifelong cure,” said Cullen Cantwell, CEO of SCDAA, “but work remains to ensure patient support programs and insurance coverage make this option accessible to all who need it. Genetic diseases do not discriminate based on race or class.”
Outlook: Cautious Optimism
While questions remain, doctors and patients groups welcomed CASGEVY’s approval as an exciting development offering new hope against a previously untreatable condition. Today’s approval marks the arrival of genetic medicines as practical, powerful therapies against complex inherited diseases.
What comes next is unclear, but the medical community looks forward with cautious optimism at the new possibilities on the horizon thanks to modern molecular medicine. As to whether the promise of genetic cures can be fully realized, only time will tell.
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