Experimental Therapy Helps Patients With Inherited Blood Disorders

Updated November 22, 2019

Two biotechnology companies recently made scientific news by pioneering effective treatment therapy for two clinical trial patients with inherited blood disorders. One patient had sickle cell anemia, the other beta thalassemia. Before treatment with CTX001, doctors thought sickle cell anemia incurable and beta thalassemia almost incurable. The best they could do was mitigate distressing symptoms.

CTX001, a gene-editing treatment for hemoglobin disorders, developed through a collaboration between CRISPR Therapeutics and Vertex Pharmaceuticals, has revolutionized medical treatment for inherited blood diseases

Following their medical breakthrough, CRISPR and Vertex now plan on enrolling 45 patients with sickle cell anemia and beta thalassemia. They will treat them with CTX001 and follow their recovery for two years.

A Confluence of New Scientific Data and Advanced Technology

Things have changed today because of a new scientific understanding. Recent findings in genetics and more advanced tools have now come together in a perfect storm.

Although CRISPR technology itself is not new—it arrived about a decade ago—its impact on health was not clear. Scientists knew that they had a revolutionary technology on their hands but did not know what to do with it. They knew about mutations in inherited blood diseases for the same amount of time, too, but didn’t know enough about all the genes involved in the genetic-based blood disorders.

What were once hopeless genetic conditions, are now amenable to effective treatments based on gene-editing because scientists can now edit gene expression. Through the process of genome editing, they can alter a selected DNA sequence deep in a living cell. After precisely snipping off a DNA strand at a targeted point, the body’s natural healing mechanism correctly repairs the broken DNA strand.

What has made CTX001 a particularly effective genome-editing treatment for rare blood disorders is that it is a safe option. Since it only affects hematopoietic stem cells in a selected area, it does not cause collateral damage by influencing cells in unrelated areas. 

Looking ahead, scientists predict that CRISPR-based medicine will target other blood disorders. Specifically, CRISPR Therapeutics now has its sights fixed on targeting elusive blood cancers.

The Benefits of Experimental Therapy 

The first two clinical trial patients to receive the new CTX001 treatment for sickle cell disease and beta thalassemia experienced impressive therapeutic benefits. The patient with beta thalassemia reported feeling as if she has received a second chance at life. At least for now, both patients are free from the necessity of frequent blood transfusions and free from their distressing symptoms. And after the experimental treatment for their inherited blood disorders, they only experienced temporary, manageable side-effects.

Therapeutic Benefits for the Patient with Sickle Cell Anemia

Sickle cell anemia affects less than 200,000 people in the United States every year and has no cure. With this inherited blood disorder, red blood cells twist into a sickle-like shape. Because these cells die early, this leaves patients with a shortage of red blood cells. Also, the odd shape of the sickle red cells blocks blood vessels. 

When a large number of blood cells get blocked, a patient will experience an occlusion of blood vessels, referred to as a vaso-occlusive crisis. This not only causes pain but also damages organs. 

The patient who received treatment for sickle cell anemia stopped suffering from blood vessel blockages. Previously, she had a vaso-occlusive crisis several times a year and hospitalized an average of three times a year. 

Therapeutic Benefits for the Patient with Beta Thalassemia 

Beta thalassemia affects about 1,000 people in the United States every year. Although a stem cell transplant can cure it, this is a risky procedure and does not benefit everyone. With this inherited blood disorder, there is insufficient hemoglobin production. Since hemoglobin, an iron-carry protein, carries oxygen in red blood cells, those with the disorder don’t have enough oxygen in many areas of their bodies.

The patient who received treatment for beta thalassemia no longer required blood transfusions. Previously, she needed about 16 a year. What’s more, her hemoglobin levels reached about 99.8% after nine months.

Genome Editing Promises New Hope

Still, it’s too early to pronounce a cure, something that researchers are always reluctant to announce prematurely. Before CRISPR Therapeutics and Vertex Pharmaceuticals can get regulatory approval for CTX001, it will, of course, require much more collected data on more clinical trial patients to show that the CRISPR-based therapy is safe, effective, and reliable.

The positive results obtained to date offer new hope that we will one day see genome editing as a cure for many inherited blood disorders.