The FDA Approved Treatment for Sickle Cell Disease

Last month, the FDA approved the first cell-based therapies for the treatment of Sickle cell disease in patients 12 years of age and older: CASGEVY and LYFGENIA.

Casgevy is the first FDA-approved treatment to utilize a novel type of genome editing technology that modifies the patients hematopoietic (blood) stem cells. The modified blood stem cells are transplanted back into the patient where they attach and multiply within the bone marrow. This leads to an increase in the production of fetal hemoglobin, a type of hemoglobin that facilitates oxygen delivery. In patients with sickle cell disease, increased levels of fetal hemoglobin prevent the sickling of red blood cells.

Lyfgenia uses a lentiviral vector to genetically modify the patient’s blood stem cells to produce a gene therapy derived hemoglobin (HbA^t87Q) that functions similarly to hemoglobin A. Hemoglobin A is normally produced in individuals not affected by sickle cell disease. Modified stem cells have a lower risk of sickling and blocking blood flow.

Both drugs require the patient to undergo chemotherapy to allow for the modified blood cells to be transplanted back into the patient. It is important to note that these drugs come with side effects, many of which are consistent with the underlying disease and chemotherapy. The most common side effects of Casgevy include low levels of platelets and white blood cells, mouth sores, nausea, musculoskeletal pain, abdominal pain, vomiting, febrile neutropenia (fever and low white blood cell count), headache, and itching. The most common side effects of Lyfgenia include stomatitis (inflammation of the lips and mouth), low levels of platelets, white blood cells, and red blood cells, and febrile neutropenia (fever and low white blood cell count). Lyfgenia also comes with a BLACK BOX WARNING due to the risk of hematologic malignancy (blood cancer) occurring in patients treated with Lyfgenia. Patients receiving this product should have lifelong monitoring for this.

The list price for Casgevy is $2.2 million, while the list price for Lyfgenia is $3.1 million. With the price set to over $2 million for both drugs, the question is whether the cost will prevent access to the millions of patients who may benefit from the treatment worldwide. Sickle cell affects an estimated 100,000 patients in the United States and about half of these individuals are lower-income individuals. The cost will pose a challenge for both public and private insurers. We can only hope that the United States’ government continues its efforts to expand access and coverage to patients affected by Sickle Cell disease.

Resources:

To learn more about Casgevy visit https://www.casgevy.com/sickle-cell-disease

To learn more about Lyfgenia visit https://www.lyfgenia.com/

CMS Launches Action for Sickle Cell Disease Month https://www.cms.gov/blog/cms-launches-action-plan-sickle-cell-disease-month

The Pharmacological Landscape of Sickle Cell Disease Continuing Education Activity