New Developments in Case of Stem-Cell Transplant Patients
Dr. Timothy HenrichamfAR-funded researcher Dr. Timothy Henrich of Harvard Medical School reported at a conference, December 5, that two patients who had appeared to be free of HIV following stem-cell transplants had each experienced a resurgence of virus. Dr. Henrich was funded by amfAR to conduct a clinical study in which he withdrew antiretroviral therapy from the two patients, since the only way to determine if a person is genuinely cured of HIV is to stop treatment and look for any signs of viral rebound.
Dr. Henrich was initially awarded a grant through the amfAR Research Consortium on HIV Eradication (ARCHE) after presenting preliminary findings on these patients at the International AIDS Conference in July 2012. The patients had been on long-term antiretroviral therapy for HIV when they developed lymphoma. To treat the cancer, each underwent reduced intensity chemotherapy followed by a stem-cell transplant. After the transplants, Dr. Henrich was unable to find any evidence of HIV infection in either patient.
With support from amfAR, Dr. Henrich and his research team withdrew the patients’ antiretroviral therapy and performed several sophisticated assays looking for signs of viral rebound in blood and other tissues. The patients had been off treatment for several months with no detectable virus. Both patients are now back on antiretroviral treatment after the researchers found evidence of virus re-emerging.
While the news was met with disappointment among the scientific community, researchers have gained important new knowledge from these two cases that will inform further cure-focused research. The cases go some way toward answering a fundamental question that continues to confound scientists: how small does the viral reservoir need to be before the risk of viral rebound is eliminated? They also underscore the need to develop better, more sensitive assays that can detect tiny amounts of virus, an area of study that is being actively investigated by amfAR-funded researchers.
Dr. Henrich is currently reviewing the data from the two patients to better understand the outcomes and to determine next steps, and amfAR will report on any further developments as information becomes available.