The United States Food and Drug Administration has granted approval for a groundbreaking gene-editing treatment designed for sickle cell patients aged 12 and above.
According to an FDA press statement released on Saturday, the treatment, consisting of two stages known as Casgevy and Lyfgenia, represents a milestone as the first cell-based gene therapies for sickle cell disease in this age group.
Casgevy, in particular, stands out as the first FDA-approved treatment utilizing CRISPR/Cas9, a novel genome editing technology, marking a significant advancement in gene therapy.
Nicole Verdun, Director of the Office of Therapeutic Products within the FDA’s Center for Biologics Evaluation and Research, highlighted the potential of gene therapy to provide more targeted and effective treatments, particularly for rare diseases with limited current treatment options.
Discussing Casgevy, Verdun explained that it is a cell-based gene therapy approved for treating sickle cell disease in patients aged 12 and older with recurrent vaso-occlusive crises.
Casgevy leverages CRISPR/Cas9 technology to modify hematopoietic stem cells, leading to increased production of fetal hemoglobin, preventing the sickling of red blood cells.
Lyfgenia, another cell-based gene therapy using a lentiviral vector, is approved for patients aged 12 and above with sickle cell disease and a history of vaso-occlusive events.
“The modified blood stem cells are transplanted back into the patient where they engraft (attach and multiply) within the bone marrow and increase the production of fetal hemoglobin (HbF), a type of hemoglobin that facilitates oxygen delivery. In patients with sickle cell disease, increased levels of HbF prevent the sickling of red blood cells.
“Lyfgenia is a cell-based gene therapy. Lyfgenia uses a lentiviral vector (gene delivery vehicle) for genetic modification and is approved for the treatment of patients 12 years of age and older with sickle cell disease and a history of vaso-occlusive events.
“With Lyfgenia, the patient’s blood stem cells are genetically modified to produce HbAT87Q, a gene-therapy-derived hemoglobin that functions similarly to hemoglobin A, which is the normal adult hemoglobin produced in persons not affected by sickle cell disease.
“Both products are made from the patient’s own blood stem cells, which are modified and are given back as a one-time, single-dose infusion as part of a hematopoietic (blood) stem cell transplant.
“Prior to treatment, a patient’s own stem cells are collected, and then the patient must undergo myeloablative conditioning (high-dose chemotherapy), a process that removes cells from the bone marrow so they can be replaced with the modified cells in Casgevy and Lyfgenia.
“Patients who received Casgevy or Lyfgenia will be followed in a long-term study to evaluate each product’s safety and effectiveness,” she said.
