Vaccine, radiotherapy combo shows hints of prostate cancer efficacy

Radiotherapy is commonly used in the treatment of prostate cancer, and immunotherapy company Advaxis ($ADXS) has seen some promising preclinical results when it combined its prostate cancer vaccine, ADXS-PSA (ADXS31-142), with a dose of radiation, in a study published in Cancer Immunology Immunotherapy.

Advaxis' prostate cancer vaccine is based on a live, attenuated strain of the bacteria Listeria monocytogenes. The bacterium produces a fusion protein of prostate-specific antigen (PSA), a prostate cancer target, combined with a Listeria protein, which triggers the immune response.

In the study, mice with tumors that expressed PSA were treated with a combination of the vaccine and radiotherapy. The tumors regressed completely in 60% of the mice that had both treatments, compared with around 10% of the mice that had one treatment or the other. When the mice that had been treated successfully were implanted with tumor cells, they did not develop cancer, which suggests that the vaccine may protect against the cancer as well as treat it.

"ADXS-PSA continues to demonstrate activity in models of prostate cancer, confirming our decision to move this construct into clinical development. The potential synergy of ADXS-PSA and radiotherapy observed in this study suggests that ADXS-PSA might be combined with other therapies that show efficacy in this type of tumor," commented Dr. John Rothman, EVP of science and operations at Advaxis.

Prostate cancer is the second most common form of cancer in the U.S., and the second leading cause of cancer death. A vaccine that can protect against recurrence as well as treat the disease could be a major change in treatment of this wide-reaching disease.

- read the press release
- see the abstract