Sickle cell disease is a debilitating, progressive and life-shortening disease. Treatments can decrease pain and prolong survival, but even so, the disease is often devastating. Until recently, the only potential curative option was a bone marrow transplant, which requires a donor, carries significant risk and only is an option for a fraction of patients. However, last December exciting, long overdue progress happened when the U.S. Food and Drug Administration approved two new life-altering treatments for SCD.
WHAT IS SCD?
SCD affects approximately 100,000 people in the U.S., most of whom are of African ancestry. Approximately one of every 365 Black or African American babies born in this country will have SCD. It is a disorder that affects hemoglobin, a protein in red blood cells that carries oxygen throughout the body. Normal red blood cells are round and flexible, allowing them to flow through the body’s small blood vessels and deliver oxygen to our tissues and organs. With SCD, there’s an abnormal form of hemoglobin called hemoglobin S. This changes the red blood cells’ shape to a crescent or sickle shape and causes red blood cells to become rigid, lack flexibility and stick together. This can block blood flow, preventing the distribution of oxygen throughout the body and causing pain and organ damage, such as stroke, heart failure and liver failure. The severity can vary among patients, and those with severe SCD have a decrease in life expectancy of 30 years on average.
A NEW TREATMENT FRONTIER
The newly approved treatments, Lyfgenia and Casgevy, are gene therapies. Gene therapy replaces or modifies abnormal genes to treat or cure disease. During gene therapy for sickle cell disease, cells are removed from the blood, re-engineered in a special facility and returned to the body through infusion. The treatment changes parts of patients’ DNA so they can create healthy, normally shaped red blood cells, mitigating the pain and organ damage. In the Lyfgenia trial, 97% of patients were free of pain crisis for the 24 months of follow up. With Casgevy, 94% of patients saw this improvement.
These gene therapies are now available at a limited number of centers in the U.S. The challenge over the next few years will be broadening access, but this still is an astonishing advance and beacon of hope for those who suffer from this painful, lifelong disease.
