Until recently, if you wanted to cure the blood disorders sickle cell and transfusion-dependent β-thalassemia patients had to attack the problem at its source and undergo a risky bone marrow transplant, which wipes out a patient’s immune system entirely and can ultimately result in a rejection of the transplanted tissue.
People living with β-thalassaemia require lifelong blood transfusions every 3 to 5 weeks, as well as additional support from medications. People with sickle cell disease experience attacks of crippling, debilitating pain, as well as life-threatening infections and low-blood oxygen levels (anemia). To make things worse, until recently the only available acute treatment options were opioids for pain management. Patients (many of them of African-American origin) suffered stigma and discrimination in the emergency room, being accused of drug-seeking behavior.
12 years ago, I was part of the team developing a drug for sickle cell disease (rivipansel), which unfortunately failed its Phase 3 trials. The experience gave me a deep understanding and appreciation of what it means to live with this disease.
Fortunately, things have changed for the better: Last year, Pfizer launched Oxbryta® (voxelotor), a daily medication.
On Friday, the FDA approved Casgevy from Vertex Pharmaceuticals and CRISPR Therapeutics, a one-time treatment for patients 12 years and older. The agency also approved Bluebird Bio's Lyfgenia gene therapy for patients 12 and older with sickle cell and a history of vaso-occlusive events.
The Casgevy approval is particularly noteworthy as it is the first-ever approved gene-editing medication using the CRISPR technology. The drug works by editing the faulty gene in a patient’s bone marrow stem cells so that the body produces functioning hemoglobin. To do this, stem cells have to undergo a process that is a testament to scientific progress and the golden age of medicine we are witnessing. They are taken out of bone marrow, edited in a laboratory, and then infused back into the patient, after which the results have the potential to be lifelong.
This marks an enormous milestone in this burgeoning field of patient care and is a first step towards widespread usage of CRISPR technology to cure once-thought incurable genetic disorders.
Read more about FDA’s approval here.