Sickle cell disease could have a cure soon, gene therapy shows good results in clinical trial
HealthScience

Sickle cell disease could have a cure soon, gene therapy shows good results in clinical trial

Results of phase 1&2 of 'LentiGlobin' therapy's trial, published by US researchers in NEJM, say durability remains to be seen. Oral pills more helpful for patients in Africa, India.

   
Representational image of a sickle blood cell beside normal red blood cells | Wikipedia

Representational image of a sickle blood cell beside normal red blood cells | Wikipedia

New Delhi: Phase 1-2 clinical trials of LentiGlobin — a gene therapy for sickle cell disease— have shown that it can help alleviate severe symptoms of this hereditary condition, which as yet has no cure. If shown to be applicable to a wider set of patients, the therapy could be the world’s first cure for the disease.

For the study (Phase 1-2 clinical trials), the results of which were published in The New England Journal of Medicine (NEJM) Thursday, researchers from the University of Alabama at Birmingham, the University of Pennsylvania, and other institutions, evaluated the safety and efficacy of the therapy in 35 patients.

Sickle cell anaemia is an inherited blood disorder, where red blood cells become crescent shaped. It causes frequent infections, swelling in the hands and legs, pain, fatigue, and delayed growth or puberty.

There is no cure for the disease, but treatment usually tries to control symptoms — such as using pain medicines during crises, antibiotics and vaccines to prevent bacterial infections, and blood transfusions.

Sickle cell disease is widespread among the tribal population in India, where about one in 86 births among the Scheduled Tribes communities suffer from it, according to data from the Ministry of Tribal Affairs.

Sustained production of antisickling haemoglobin

In 2015, the US Food and Drug Administration (FDA) granted ‘Breakthrough Therapy Designation’ to LentiGlobin. A breakthrough therapy designation is given to a drug that treats  serious or life-threatening conditions, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over available therapies.

LentiGlobin inserts a gene into the patient’s hematopoietic stem cells — which develop into all types of blood cells — in the lab. Then these modified cells are transferred back to the patient.

The gene — known as beta-globin — produces an antisickling haemoglobin called HbAT87Q, which prevents or counteracts the sickling of red blood cells.

In the study, the team looked at the number of severe vaso-occlusive events — when sickled red blood cells block blood flow to the point that tissues become oxygen-deprived — after LentiGlobin infusion among patients.

The team found that one-time treatment with LentiGlobin resulted in sustained production of HbAT87Q in most red cells, leading to reduced hemolysis (the destruction of red blood cells) and complete resolution of severe vaso-occlusive events.


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Difficult and expensive treatment

In a linked editorial (published in NEJM), Martin Steinberg, MD, professor of medicine at Boston University School of Medicine, said that while patients in the study no longer had symptoms of sickle cell disease, most continued to have a shorter-than-normal lifespan for their red blood cells. This could be associated with some complications in the longer term.

Steinberg said that for patients to accept the treatment, which is difficult and expensive, it must be curative or nearly curative, must and last a lifetime.

“At this point, we do not yet know the sustainability of the results, but based on this study the prospects seem good,” he said.

Steinberg acknowledged, however, that any highly effective gene therapy would not improve the health of most people with sickle cell disease throughout the world.

“Most patients with this disease live in Africa and India where access to highly technological health care is limited. What is needed are more drugs that can be taken orally and increase foetal haemoglobin levels. This will have a higher likelihood of benefiting populations suffering the most from this disease,” he added.

(Edited by Poulomi Banerjee)


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