December 11, 2012 | by Shawn Le
On the surface, the idea of using HIV to treat leukemia might seem far-fetched, but researchers from the University of Pennsylvania were recently able to harness HIV's ability to infect white blood cells, developing what seems to be a cancer cure – or at least total remission – for a handful of patients. And they're not alone in using this increasingly promising approach.
The Pennsylvania team's HIV-based treatment, presented at the American Society of Hematology meeting and reported this week by the New York Times, is a new addition to the numerous treatments in development using T cells, a type of white-blood cell. Known as immunotherapeutics, these therapies use a patient's own immune system to fight disease.
At City of Hope, the Department of Cancer Immunotherapeutics and Tumor Immunology is developing T cell-based immunotherapeutics against brain tumors, lymphoma and breast cancers.
Such therapies are most often aimed at rebooting the body's immune system to overcome cancer cells' abilities to evade identification, attack and eradiation; the therapies also boost production of immune cells, further helping overwhelm the cancer.
The University of Pennsylvania's leukemia treatment gets a boost from HIV's ability to infect cells, which helps spread the treatment throughout the body.
In the case cited by the New York Times, researchers reprogrammed T cells from then-6-year-old Emma Whitehead using neutered HIV – its infection prowess untouched but its disease genes replaced with anti-cancer genes. When the cells were reinfused into Emma, the viral package infected the other T cells in Emma's body, creating a new army of leukemia-targeted T cells that destroyed her cancer.
Twelve patients, including Emma, were treated with the HIV immunotherapeutic, but not all patients experienced remission of their cancers. One patient experienced a cancer recurrence.
In fact, although Emma's results were positive, she did endure harrowing fevers and chills – and dangerous blood pressure drops – during treatment, prompted by her rebooted immune system. More research is needed to understand why treatment results varied.
City of Hope's own immunotherapy research has identified cancer-specific receptors that can be used to target treatment, discovered specific T cells that can track down cancer cells hiding in lymph nodes, and opened clinical trials using central memory T cells to potentially provide immunity against cancer relapse. Stephen J. Forman, M.D., chair of City of Hope's Department of Hematology & Hematopoietic Cell Transplantation and the Francis and Kathleen McNamara Distinguished Chair in Hematology and Hematopoietic Cell Transplantation, is leading clinical trials on these immunotherapeutics.
“Our use of central memory T cells as part of an autologous transplant is unique to our therapy and sets our approach apart from other T cell treatments in development,” said Forman in a previous interview. “Central memory T cells have the potential to establish a persistent, lifelong immunity to help prevent recurrence of lymphoma after [a bone marrow] transplant.”
For more on cancer immunotherapeutics, visit the City of Hope's Cancer Immunotherapeutics Program online.