New Evidence Supports Potential Cure for HIV
Researchers announced on Monday, March 4th, at the Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, that a bone marrow transplant has left the so-called “London Patient” in long-term remission, marking the second of such cases. The next day, a different team announced a potential third case with the “Düsseldorf Patient,” who received a similar treatment.
Attendees were described as having “a sort of electric hope” at the dual announcement. Dr. Steve Deeks, AIDS specialist at UC San Francisco, added that “the whole approach to a cure [to HIV/AIDS] is shifting more from aspiration to something that people are realizing could be feasible.” Others were similarly positive; Richard Jeffreys, of US-based HIV/AIDS advocacy organization Treatment Action Group, said that “while two or three people is a drop in the ocean compared to the 35 million HIV positive people in the world, it’s a whole lot better than zero.”
Others had somewhat more tempered responses. Timothy Heinrich, also of UC San Francisco, noted that “finding a scalable, economically feasible cure, or HIV remission, is going to be difficult.” In spite of that, he remained hopeful that these small steps of progress will keep people motivated and engaged in finding the cure.
Bone marrow transplants are a treatment for conditions affecting the production of blood cells, particularly cancers such as leukemia. The procedure involves transplanting the bone marrow from a healthy donor to an unhealthy patient whose own bone marrow is too damaged to produce stem cells. These stem cells, which are produced by bone marrow, can turn into hematocytes (blood cells) which perform various crucial functions throughout the body, including but not limited to delivering oxygen, fighting infection, and stopping bleeding.
When it comes to treating HIV, the donor must be in possession of the CCR5-Δ32 genetic mutation resulting in non-functional receptors on their blood cells’ surfaces, which would otherwise act as receptors for the virus. This effectively grants the cells resistance to the virus, which can then be conferred to a recipient by transplantation. It is an expensive and risky procedure with possible side effects in addition to the already-present side effects of the chemo- and/or radiotherapy. These side effects include rejection of the transplanted cells by the body and anemia due to reduced blood cell count.
In order to meet the criteria for being cured of HIV, the patient must show no signs of the presence of infectious HIV after being off antiviral drugs for 18 months. As of now, the Düsseldorf Patient has only been off antiviral drugs for three months, but scientists are hopeful that soon he will constitute the third case in which a patient was successfully cured of the virus through the use of a bone marrow transplant
The first case occurred over a decade ago, when the “Berlin Patient” - who has since been identified as Timothy Ray Brown, an American citizen - was cured by a team led by German hematologist Gero Hütter. Hütter first discovered that stem cell transplants from donors in possession of the aforementioned CCR5-Δ32 mutation could effectively combat the disease.
It is important to note that the risky nature of bone marrow transplants means that they can only be used to treat HIV in patients already diagnosed with cancer, and even then only as a last resort. All three of the patients that have been cured of HIV up to this point were also suffering from cancer and received the treatment primarily for their cancer rather than for HIV. What this week’s results show is that the case of the Berlin Patient in 2008 was no fluke, which will help inform the use of gene therapy and similar strategies to treat and eventually cure the virus on a larger scale in the future.
Brown, the Berlin Patient, had this to say of the development: “I’m so happy to have somebody to join my family. It’s a very small family, I’m the only person in it so far until this patient. I want to encourage the brilliant scientists that have been working on finding HIV cures to keep going and come up with something that is more viable to everyone else.”