HIV Drug Blocks Bone Metastasis in Prostate Cancer Patients

According to a new study, a CCR5-blocking drug used to treat HIV may also be able to slow prostate cancer metastasis.

The antiretroviral drug maraviroc, a CCR5 receptor antagonist used in the treatment of HIV, may also be able to block bone metastases in prostate cancer patients, a new study shows.

The study, published in the December 1, 2014 issue of Cancer Research, indicates that CCR5 may play a role in spreading prostate cancer to the bone.

"Because this work shows we can dramatically reduce metastasis in pre-clinical models, and because the drug is already FDA approved for HIV treatment, we may be able to test soon whether this drug can block metastasis in patients with prostate cancer," said senior author Richard Pestell, MD, PhD, MBA, director of the Sidney Kimmel Cancer Center at Thomas Jefferson University, in a press release.

Dr. Pestell’s lab had previously shown that CCR5 signaling was essential to the spread of breast cancer to the lungs. Building on this work, Dr. Pestell’s team evaluated whether CCR5 was also involved in prostate cancer metastasis.

The researchers analyzed the genes of metastasized bone and brain tumors of test animals and found that the genes that were driving the cancer were also involved in the CCR5 signaling pathway. The research team also administered the CCR5-blocking maraviroc to test animals and found that the overall metastatic load in the bone, brain, and other organs of animals given the drug was 60% less than that of control animals.

To determine if these finding might be similar in human prostate cancer, the researchers analyzed the genomic data of patients with prostate cancer and found that CCR5 was expressed more in prostate cancer tissue than in normal tissue, particularly so in metastatic tumors.

"In fact, we noticed that patients who had a lower expression of the CCR5-pathway genes had a longer survival times, whereas high expression of these CCR5 genes was associated with a shorter overall survival," said co-first author Xuanmao Jiao, PhD., an instructor in the Department of Cancer Biology at Thomas Jefferson University.

The research team now hopes to develop clinical trials using CCR5 pathway activation as a companion diagnostic.