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Tuesday 20th March 2018

Gene Therapy Scientists Move Closer to 'Cure' For Sickle Cell

Science & Technology

7Dnews London - Reuters

Tue, 12 Mar 2019 18:00 GMT

National Institutes of Health (NIH) Director Collins said sickle cell anaemia is a frustrating disease for patients and doctors alike. There is no universal cure and most of the current treatment is limited to simply pain management. Furthermore, the pain is excruciating.

The 29-year-old Lynndrick Holmes of Mobile, Alabama, said "There's so many ways to describe it… But for me, it feels like my body is starving for oxygen and it's suffocating... I feel myself dying."

Holmes is one of nine test patients in a small clinical trial at the NIH in which researchers believe they may have discovered an effective treatment for sickle cell anaemia. This painful and debilitating disease inflicts many millions of people across the globe, mostly of African heritage and includes some 100,000 African Americans in the United States, as reported by Reuters.

He discovered the trial after searching for alternative treatment options on the internet. The NIH team leading the effort are optimistic the treatment could be a cure.

The researchers said they have used gene therapy techniques to add a "corrected" gene for healthy red blood cells into the bodies of nine test patients, replacing their diseased red blood cells caused by sickle cell anaemia, effectively ridding them of signs of the disease. NIH Director Francis Collins described the trial results as seemingly "spectacular".

Sickle cell disease is an inherited blood disorder that causes protein crystals to form inside red blood cells, changing their shape from a flat disk into a crescent or sickle shape that then clogs up the small blood vessels and results in terrible episodes of pain and organ damage.

Collins said the disorder comes essentially from a "misspelling" in the gene for one of the proteins. In the clinical trial, a normal copy of the gene with the "correct spelling" for healthy red blood cells was placed inside a virus that allowed the good gene to multiply many times over. The virus was then introduced into the patient's bodies via bone marrow transplants.

The researchers said within two or three months, the nine patients showed signs of remission and were starting to discover normal health for the first time in their lives.

Dr John Tisdale, the molecular haematologist behind the clinical trial stated, "We're simply adding the gene. We leave the defective gene intact. This is what is called gene addition therapy."

The NIH's Cellular and Molecular Therapeutics lab is where the testing for the trial was conducted.

The virus in this case was HIV. But the researchers said they used a version of the virus that lacked the harmful elements that could cause AIDS. Tisdale called the HIV virus a "Trojan horse" that won't cause AIDS but was very good at delivering the corrected gene into the body.

For Tisdale, the most remarkable moment of the trial was when he noticed the normalising haemoglobin levels in his patients.

The researchers at the NIH believe there are some 7,000 other diseases that could benefit from the single-gene addition therapy used in the sickle cell trial, including a white blood cell disorder called chronic granuloma and, possibly, one-day cystic fibrosis.

Neither Collins nor Tisdale think the lengthy and costly protocol of the clinical trial -- which includes chemotherapy and months of close medical supervision -- can be scaled out to help the millions of sickle cell patients in African nations where the disease is more prevalent, especially in the Sub-Saharan region.

But they believe the basic premise of introducing a corrected gene into the body holds promise for all nations provided a simpler, cheaper and less toxic delivery system than bone marrow transplant and the accompanying chemotherapy can be found.

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