Boston researchers are reporting an intriguing finding in two of their patients with longstanding HIV infections that may bolster a new approach to fighting the disease.
The Brigham and Women’s Hospital scientists say the patients, who underwent bone marrow transplants several years ago for cancer, have no detectable levels of HIV in their blood cells anymore, despite recently stopping powerful antiretroviral medications that are typically given to those infected with the virus.
“I don’t want to use the ‘cure’ word,’’ said Dr. Timothy Henrich, a Brigham infectious diseases associate physician who is leading the study. “If they remain virus-free in a year, or even two years, after [stopping] therapy, then we can make a statement that the chances of the virus returning are very low.’’
Henrich’s team is presenting its findings Wednesday at the International AIDS Society Conference in Malaysia.
Last summer, Henrich and coauthor Dr. Daniel Kuritzkes announced that HIV, the virus that causes AIDS, was easily detected in the patients’ blood prior to their bone marrow transplants but could not be found eight months after the transplant.
At that time, the men remained on HIV medications — prompting some scientists to express skepticism, because they linked the apparent disappearance of the patients’ virus to their continued HIV medications, and not the bone marrow transplants.
Since then, the two patients stopped taking the medications, with one coming off 15 weeks ago, and the other seven weeks ago.
The researchers are carefully testing the patients’ blood weekly, and say they have not found signs of HIV. Henrich said they also removed and tested a tiny piece of tissue from one of the patient’s intestines — where the wily HIV virus is believed to lurk — and that came back negative, too.
“HIV could still be hiding in the brain, gut or lymph nodes,’’ Henrich said.
Dr. Jay Levy, an HIV researcher at the University of California, San Francisco, said the Boston results are encouraging but the patients need to be monitored much longer to know whether the virus has been truly knocked out.
The Boston patients both suffered from Hodgkin’s lymphoma, a cancer of the blood. After chemotherapy and other treatments failed, doctors performed bone marrow transplants to replace the patients’ cancerous blood cells with healthy donor cells. They discovered that within eight to nine months of the transplants, the patients’ blood showed no trace of HIV, and the patients have also remained cancer free.
The Boston findings are similar to results widely reported in 2009 by German doctors who said that an American, Timothy Ray Brown, was given a bone marrow transplant for leukemia and appeared to have been cured of HIV, too. He is believed the only patient cured of HIV.
But Brown, known as the “Berlin patient,’’ received bone marrow from a donor who carried a rare gene mutation, CCR5-delta32, which is thought to provide resistance to HIV. Previously, researchers had not observed similar results with ordinary donor cells, such as those given to the Boston patients.
Henrich and other researchers say bone marrow transplants, which are risky and can be lethal, are not a practical or ethical approach to treating HIV, especially in patients who do not have cancer. But the Boston findings may help researchers better understand how and where HIV persists in the body, and also determine whether the rare CCR5-delta32 mutated genes would be needed to achieve a cure using an approach other than transplanting bone marrow from a donor.
Levy’s lab is studying whether bone marrow cells extracted from someone infected with HIV can be genetically altered to resemble the CCR5-delta32 mutation. The goal is to give HIV patients their own genetically altered cells to wipe out the virus, while not exposing them to the risk of traditional bone marrow transplantation of a patient’s immune system rejecting the donor’s cells.
Henrich said his team worked closely with the patients’ cancer specialists, an independent board at the hospital that monitors research, and outside specialists to ensure the patients were not pressured to take part in the study, and that they understood that stopping their HIV medications carries a risk of the virus resurfacing.
“This is unknown territory and we made that very clear to the patients, who are both very curious to know if they still have HIV in their bodies,’’ Henrich said.
The two, who were not identified, were “very positive’’ about participating to help further research, Henrich said. Still, they are anxious.
“They have been taking anti-retroviral therapy for years and years,’’ he said, “and all of a sudden their research doctors are telling them to stop taking it.’’
All agreed that if HIV is detected in the patients, they will be returned to antiretroviral medications, he said.