Two men unlucky enough to get both HIV and cancer have been seemingly cleared of the virus, raising hope that science may yet find a way to cure for the infection that causes AIDS, 30 years into the epidemic.
The researchers are cautious in declaring the two men cured, but more than two years after receiving bone marrow transplants, HIV can't be detected anywhere in their bodies. These two new cases are reminiscent of the so-called "Berlin patient," the only person known to have been cured of infection from the human immunodeficiency virus.
These two cases, presented as a “late-breaker” finding on Thursday at the 19th annual International AIDS Conference in Washington, D.C., are among the reasons that scientists have been speaking so openly at the event about their hopes of finding a cure.
“Everyone knows about this ‘Berlin patient’. We wanted to see if a simpler treatment would do the same thing”, said Dr. Daniel Kuritzkes of Brigham and Women’s Hospital in Boston, who oversaw the study. The widely publicized patient, Timothy Brown, was treated for leukemia with a bone marrow transplant that happened to come from a donor with a genetic mutation that makes immune cells resist HIV infection. The transplant replaced his own infected cells with healthy, AIDS-resistant cells. He is HIV-free five years later.
AIDS patients are susceptible to cancers, but they usually stop taking HIV drugs before receiving cancer treatment. “That allows the virus to come back and it infects their donor cells,” Kuritzkes said.
About 34 million people are infected with HIV, the virus that causes AIDS, globally; 25 million have died from it. While there’s no vaccine, cocktails of powerful antiviral drugs called antiretroviral therapy (ART) can keep the virus suppressed and keep patients healthy. No matter how long patients take ART, however, they are never cured. The virus lurks in the body and comes back if the drugs are stopped. Scientists want to flush out these so-called reservoirs and find a way to kill the virus for good.
Brown, and now these two other men, offer some real hope.
Dr. Timothy Henrich and colleagues at Brigham and Women’s Hospital launched a search about a year ago for HIV patients with leukemia or lymphoma who had received bone marrow stem cell transplants. Bone marrow is the body's source of immune system cells that HIV infects and it’s a likely place to look for HIV’s reservoirs.
“If you took an HIV patient getting treated for various cancers, you can check the effect on the viral reservoirs of various cancer treatments,” Kuritzkes, who works with Henrich, said. They found the two patients by asking colleagues at Dana-Farber Cancer Institute in Boston which, like Brigham and Women’s, is associated with Harvard Medical School.
Both men had endured multiple rounds of treatment for lymphoma, both had stem cell treatments and both had stayed on their HIV drugs throughout. “They went through the transplants on therapy,” Kuritzkes said.
It turns out that was key.
“We found that immediately before the transplant and after the transplant, HIV DNA was in the cells. As the patients’ cells were replaced by the donor cells, the HIV DNA disappeared,” Kuritzkes said. The donor cells, it appears, killed off and replaced the infected cells. And the HIV drugs protected the donor cells while they did it.
One patient is HIV-free two years later, and the other is seemingly uninfected three-and-a-half years later.
“They still have no detectable HIV DNA in their T-cells,” Kuritzkes said. In fact, doctors can’t find any trace of HIV in their bodies -- not in their blood plasma, not when they grow cells in the lab dishes, not by the most sensitive tests.
Can the patients be told they are cured?
“We’re being very careful not to do that,” Kuritzkes said.
For now, both men are staying on AIDS drugs until they can be carefully taken off under experimental conditions. "We are not saying, “You are like the Berlin patient’.”
Although the men are HIV-free, Kuritzkes says it's been an arduous experience for them. After being diagnosed HIV-positive, one underwent rounds of chemotherapy for Hodgkin’s disease, a kind of lymphoma, before receiving the final bone marrow transplant, called an allogeneic bone marrow transplant. It is not an easy treatment to endure.
The men, one from Boston and one from New York, were not initially told their HIV had seemingly disappeared. When researchers realized news media would cover the report, they were informed.
Neither man is being identified for privacy reasons but one is in his 50s and has been infected since the beginning of the AIDS epidemic in the early 1980s. The other man, in his 20s, was infected at birth.
The findings may not apply to all patients. Both men were a little unusual in that they had a genetic mutation that can make immune cells resistant to infection by HIV. Their new immune cells, however, which came from the donors, are fully susceptible to the virus.
“We’re never really going to be able to do bone marrow transplants in the millions of patients who are infected,” Kuritzkes said. “But if you can stimulate the virus and eliminate those cells, we can protect the remaining cells from being infected.”
Separately, two other studies presented at the conference have scientists optimistic about a cure. In one, a cancer drug called vorinostat flushed out latent HIV from a handful of patients, offering the possibility of killing these latent reservoirs. In another, about 15 French patients who got HIV drugs very early after their infections were able to stop treatment and don’t show any symptoms years later, even though they are still infected.
Organizers of the conference say the findings provide an argument for treating patients early. “(These studies) give us reason for enthusiasm, that ultimately we are going to get to where we needed to go, which is to cure people with HIV infection,” said Dr. Steven Deeks, an HIV expert at the University of California, San Francisco.
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