One year after the FDA approved Casgevy and Lyfgenia, two gene therapies for sickle cell disease, their adoption has been slower than anticipated. Despite the therapies' potential to nearly cure the disease, only a handful of patients have received infusions, highlighting the challenges in launching such complex treatments.
Hurdles to Adoption
Several factors contribute to the slow uptake. The treatment process is lengthy, often taking up to a year from initial evaluation to infusion. This includes multiple hospital visits, extensive medical consultations, and preparatory chemotherapy with busulfan, which can cause significant side effects like infertility. Furthermore, Lyfgenia's label carries a risk of blood cancer.
"It’s a complicated process," said Akshay Sharma, a pediatric hematologist at St. Jude Children’s Research Hospital. "It's not just the patient preparation and manufacturing of the product that takes time, but centers have to be accredited. Everything from resources to staff and training has to be completed before you can even enroll a patient."
Logistical and Economic Challenges
Access to accredited treatment centers remains a barrier. As of recently, half of U.S. states lack a center that can administer either Lyfgenia or Casgevy. Vertex Pharmaceuticals counts 33 activated treatment centers in the U.S., while Bluebird bio counts 50.
The high cost of the therapies also plays a role. Casgevy is priced at $2.2 million, while Lyfgenia costs $3.1 million. While insurance coverage is generally approved, some patients are deterred by the perceived cost, according to Alexis Thompson, the chief of CHOP’s hematology division.
Patient Hesitancy and Alternative Options
There is also hesitancy and mistrust within the sickle cell community regarding new treatments. "There’s a lot of not only misunderstanding, but also mistrust of the medical research establishment in general among patients with sickle cell," said Sharma.
Some patients may also opt for alternative treatments or clinical trials testing newer experimental medicines. Additionally, not all patients are suitable candidates for gene therapy, particularly those with mild disease or those unable to endure chemotherapy conditioning.
Clinical Promise and Future Outlook
Updated trial data presented at the American Society of Hematology demonstrated the durable effects of both Casgevy and Lyfgenia. These therapies work by genetically engineering a patient’s own stem cells to improve the health and function of red blood cells, effectively eliminating the debilitating pain crises associated with severe sickle cell disease and reducing the need for blood transfusions.
Despite the current challenges, both Vertex and Bluebird anticipate increased adoption as more treatment centers become accustomed to providing the therapies and as patients who have begun the preparation process move forward with infusions. However, Martin Steinberg, a hematologist at Boston Medical Center, believes that gene therapies will remain a niche product for the time being.
