Hope for sickle cell and HIV patients

In Addis Ababa, Ethiopia

The world could soon get a cure for sickle cell, a hereditary genetic disorder that affects three in 10 people living in Western and Coastal parts of Kenya.

The US National Institutes of Health (NIH) and the Bill and Melinda Gates Foundation have pledged to jointly invest $200 million (about Sh20.5 billion) over the next four years to achieve affordable gene therapy-based cures for sickle cell disease (SCD). Initially, each of the two organisations plans to spend $100 million (Sh10.5 billion).

Gene therapy is a relatively new area of medicine designed to replace faulty genes in the body that are responsible for a disorder, and has been responsible for new treatments for blindness and certain types of leukaemia.

LOW COST

The investment aims to produce gene-based treatments that can be administered using low-cost delivery mechanisms for sickle cell disease and HIV.

This innovation is expected to result in clinical trials where the treatments, if successful, will be tested on patients in the United States and countries in Sub-Saharan Africa within the next seven to 10 years, director of the NIH, Francis Collins, said.

Dr Collins added the collaboration would focus therefore on "access, scalability and affordability" to make sure the eventual treatments are available globally.

“Our intention is to have a simple and affordable treatment options for the many patients who are not able to afford. The innovation therefore, must be achievable and doable in Africa,” explained Dr Collins, a physician-geneticist.

Gene therapy is a technique that uses genes to prevent or treat a disease. This can be either through replacing or inactivating a disease-causing gene or introducing a new or modified gene to help treat the disease.

On the flipside, gene editing uses different technologies to modify DNA at a specific spot, allowing scientists to remove, add or replace the DNA where it was cut in order to correct a genetic disorder.

Even though sickle cell is inherited and HIV is acquired, both diseases disproportionately affect African people.

Sickle cell disease is a group of inherited red blood cell disorders characterized by the presence of an abnormal protein in the red blood cells, causing the feet and hands to swell, fatigue, jaundice, and episodic or chronic pain.

The disease is most common in Africa, and affects up to two per cent of the population in tropical countries such as Cameroon, according to the World Health Organisation (WHO). In many sub-Saharan African countries like Kenya, accurate data about the disease is unavailable.

Speaking on the sidelines of the Grand Challenges annual meeting in Addis Ababa, Ethiopia he added that the goal is to develop an apparatus which can be administered as an injection to patients which will then travel into the body and tweak the DNA to either corrects the gene responsible for mutation or promote production of fetal haemoglobin gene expression that can then achieve normal haemoglobin.

On the other hand, the proposed cure for HIV would involve targeting the reservoir of an inactive viral form that has been integrated into the genes of a host cell (known as proviral DNA) and lurks inside a small number of cells even after many years of the patient taking Anti-retroviral Therapy drugs (ART).

It is estimated however, that in some parts of Kenya, the prevalence of the disease can be as high as 35 per cent in coastal counties and 24 per cent in Western. These are areas prone to malaria.

Normally, red blood cells deliver oxygen throughout the body, through a red protein responsible for transporting oxygen in the blood known as haemoglobin, which helps the cells bend and adjust to fit into narrow blood vessels, to deliver blood rich in oxygen to tissues and organs. contrarily, rigid and misshapen sickle cells with abnormal haemoglobin, get stuck in the narrow blood vessels as they try to push through.

This prevents blood with oxygen from reaching tissues and organs, causing anaemia that leaves the patient tired and out of breath and sudden attacks of severe pain called sickle cell crises.

Moreover, without adequate oxygenated blood, tissues and organs such as the spleen, liver and kidneys suffer damage over the years, with potentially life-threatening results.

With each sickling cycle, the cells accumulate damage, becoming denser than normal red blood cells. And complications become more likely as the patient gets older and symptoms persist.

When it comes to HIV, antiretroviral therapy (ART) are now able to reduce patients' viral load to the point that they are undetectable and cannot be further transmitted.

But "a major goal is to find a cure, whereby lifelong ART would not be required," said the NIH's Anthony Fauci.

Though SCD is a genetically inherited disease, and HIV is acquired from infection, gene-based treatments are said to hold promise for both, and "many of the technical challenges for gene-based cures are expected to be common to both diseases."