Doctors Investigate CRISPR Gene-Editing for Treatment of Sickle Cell Disease

US Doctors Testing CRISPR for Sickle Cell Treatment

Doctors in America are currently investigating whether they can rely on CRISPR gene-editing for treating people with severe sickle cell disorder.

Image of Sickle Cell Anemia Courtesy of Bruce Blaus

Medical experts have been anticipating this trial since when it was first revealed towards the end of 2018. CNN reports that it is finally underway, although the organizers have yet to make public how far they have gone with the study.

Adult sickle cell patients numbering up to 45 are required for the trial. These will be the first with a genetic disease in America to be treated with the CRISPR technology.

The estimate has that about 100,000 people in the U.S. Suffer from sickle cell disease. The bulk of these individuals comprises people of African descent.

Sickle cell disease is a genetic disorder characterized by malformed hemoglobin in red blood cells. Hemoglobin is a protein that assists in circulating oxygen throughout the body. An abnormality of the protein can lead to clogging within small blood vessels, leading to a variety of unpleasant symptoms.

People with sickle cell disease typically experience pain and suffer anemia. The disorder can result in organ damage and blindness. Those having it typically have a shorter average lifespan than that of the general population.

In this trial, doctors will use CRISPR, an innovative technology for editing genes, to increase the production of fetal hemoglobin. This type of blood protein makes it difficult for cells to form sickles or stick together as is the case of this disease.

A representative of a study co-sponsor, Vertex Pharmaceuticals, said more patients are still needed for the trial.

Revolutionary treatment technique

Interest in the use of CRISPR for treatment of diseases is increasing daily in the biotech industry. It is believed to be capable of changing the world.

In the current trial, scientists will use CRISPR to modify premature cells extracted from the bone marrow of patients. The ultimate aim of the process is to make fetal hemoglobin. The cells are then used to replace the ones in the bone marrow after being treated with chemotherapy.

A single CRISPR treatment may be all that is needed to treat patients.

Dr. Alexis Thompson, a pediatrics professor at Feinberg School of Medicine of Northwestern University, who is not part of the trial team, explained to CNN that patients who could be cured with bone marrow transplant do not find a perfect and a willing bone marrow donor in most cases.

With CRISPR gene editing, a patient is his or her own donor. This is why the ongoing trial is a highly anticipated one.

“It’s terribly exciting that there is so much attention to cutting-edge science and a condition that has lagged far behind many other medically important diseases,” said Thompson, who is also the head of a hematology section of the Ann and Robert H. Lurie Children’s Hospital of Chicago.

The hereditary blood disorder beta thalassemia and genetic eye disorder are among other conditions, that researchers are currently studying to find out how CRISPR may be helpful for their treatment.

Risks involved

However, in spite of how greatly CRISPR might help in treating sickle cell disease, experts have been quick to point out that there are also risks involved.

Concerns have to do mostly with the use of chemotherapy in CRISPR for sickle cell disease. It is well known that this treatment, which is commonly used for getting rid of cancerous cells, often comes with serious side effects. For instance, it can result in fertility issues or even cancer of blood cells.

Dr. Jane Little, sickle cell program director at the University of North Carolina at Chapel Hill, who is also not involved in the study, told CNN that there is the possibility, although less likely, of modifying wrong genes as well. More genes than necessary may also be removed.

Medical experts are not sure yet whether treatment with CRISPR will yield desired results. This is partly because it is not yet clear how much of fetal hemoglobin will be sufficient to treat a patient.

A number of other new drugs for treatment of sickle cell disease are expected to reach the stage of seeking FDA approval within the next year, or thereabouts. One of such drugs promises to help improve fetal hemoglobin production.

Thompson said there will need to compare the efficacy of the imminent therapies and determine what classes of patients benefit the most from each one.