Advances in stem cell treatment give hope to millions with 'incurable' diseases

Timothy Ray Brown poses for a photograph, Monday, March 4, 2019, in Seattle.

The "London Patient" is only the second person known to have shaken off the HIV virus during a 40-year AIDS epidemic that has infected 70 million people and killed half of them. It's the second such success including "Berlin patient" Timothy Ray Brown. The blood treatments the Berlin and London patients had have failed in other patients.

"Coming 10 years after the successful report of the 'Berlin Patient, ' this new case confirms that bone marrow transplantation from a CCR5-negative donor can eliminate residual virus and stop any traces of virus from rebounding", said Sharon Lewin, director of the Peter Doherty Institute for Infection and Immunity at the University of Melbourne, in a statement.

It is the second time a patient has ended up in remission from HIV.

Such transplants are risky and have failed in other patients.

Researchers are developing better antiretroviral treatments, prevention methods, and vaccines to halt infections while continuing to pursue a cure for those already infected. Certain HIV antibodies and proteins declined in the blood of both men, she points out, which might offer a helpful early indicator of whether a cure strategy is working prior to stopping ARVs. "These new findings reaffirm our belief that there exists a proof of concept that HIV is curable".

Gupta, now at Cambridge University, treated the London patient when he was working at University College London.

The patient has not been identified. It's unclear why he waited that long. He received a bone-marrow transplant that appeared able to cure both his cancer and HIV.

Doctors in London say they have apparently eradicated HIV from a patient's body. For one thing, the rare mutation in this case, a variant of a receptor called CCR5, only blocks one variety of HIV. "That's why this has not been observed more frequently".

These types of stem-cell transplants require harvesting blood marrow from a compatible human donor, wiping out the patient's own immune system, then reconstituting it with the donated marrow.

Nearly three years after receiving bone marrow stem cells from a donor with a rare genetic mutation that resists HIV infection - and more than 18 months after he stopped taking antiretroviral drugs - highly sensitive tests still showed no trace of the London patient's previous HIV infection.

Usually, HIV patients expect to stay on daily pills for life to suppress the virus. More recently, researchers reported that a bone marrow transplant recipient in Minnesota had viral remission lasting almost 10 months after an analytic treatment interruption, but he too ultimately experienced viral rebound.

In another closely watched set of cases, three HIV-positive patients from the Boston area received transplants of blood stem cells that did not carry the mutation. Scientific research into the complex virus has in recent years led to the development of drug combinations that can keep it at bay in most patients. Instead, they say the patient is in remission.

That does not mean donor stem cells will become a widely used treatment for HIV.

16 months after the stem-cell transplant, September 2017, the man went off his antiretroviral drugs for HIV. There are complications too. In one case, these variants maintained the infection after a stem cell transplant.

Compared to Brown, the London patient had a less punishing form of chemotherapy to get ready for the transplant, didn't have radiation and had only a mild reaction to the transplant.

Brown, though, had undergone more severe treatment than the London patient and for a while researchers believed that his near-death experience was key to curing HIV.

Vanessa Coleman

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