Six injections of OncBioMune Pharmaceuticals' prostate cancer vaccine ProscaVax stopped the progression of the disease in 80 percent of patients in a Phase 1 clinical trial, the company announced. The results applied to patients who had been treated for 19 weeks. All the participants had cancer that had returned after other treatment regimens. “All the data to date is consistent with previous study data showing ProscaVax elicits immune responses to fight tumor growth in prostate cancer,” Dr. Jonathan Head, chief executive officer of OncBioMune, said in a press release. “We are impressed that 80 percent of the patients treated with ProscaVax demonstrated stable disease" — that is, no progression. ProscaVax immunizes patients against the protein prostate specific antigen, or PSA, high levels of which are associated with cancer. The vaccine includes PSA plus two immune system activators, interleukin-2, or IL-2, and granulocyte-macrophage colony-stimulating factor, or GM-CSF. It is designed to boost the immune response against prostate cancer cells. The ongoing Phase 1 trial (NCT02058680) is evaluating the vaccine's effectiveness against recurrent prostate cancer in patients whose PSA levels had increased for more than six months before the trial started. The study is also assessing the vaccine's safety. In the Phase 1a part of the trial, the 20 participants received vaccine shots at weeks 1, 2, 3, 7, 11, and 15. At 19 weeks, in the first patient follow-up, researchers discovered that the cancer of 16 of the 19 patients had failed to progress. Among the four patients whose disease progressed, three had higher PSA levels. Imaging indicated that the cancer of the other had spread to the brain. Researchers also found the vaccine to be safe.