BioSante Pharmaceuticals, Inc. (NASDAQ: BPAX) today announced publication of results from a Phase I dose escalation clinical study that show its GVAX Prostate cancer vaccine in treating metastatic castration-resistant prostate cancer patients (mCRPC) in combination with ipilimumab (Ipi; Yervoy; BMS), resulted in 53 percent of patients achieving at least stable disease, with two patients showing clear regression of metastases. In addition, 23 percent of patients in the higher dose cohorts had confirmed partial PSA (prostate specific antigen) responses of greater than 50 percent from baseline.
The study, titled, “Combined Immunotherapy with Granulocyte-Macrophage Colony-Stimulating Factor-Transduced Allogeneic Prostate Cancer Cells and Ipilimumab in Patients with Metastatic Castration-Resistant Prostate Cancer: a Phase 1 Dose Escalation Trial” was published in current issue of The Lancet Oncology (February 2012). The study combined fixed doses of GVAX Prostate in combination with escalating 0.1, 0.3, 1.0, 3.0 and 5.0 mg/kg doses of Ipi. The study enrolled 12 patients in three dose escalation cohorts and 16 patients in an expansion Ipi 3.0 mg/kg cohort. The reported duration of disease stabilization ranged from 3-27 months, and the median duration of PSA response was 12 months, (range 2-21 months). There were no serious adverse events in the lower dose Ipi cohorts and administration of immunotherapy was well tolerated and safe. The investigators concluded that, “Further research on the combined treatment of patients with mCRPC with vaccination and Ipilimumab is warranted.”
The 28 patient Phase I study was conducted by researchers at the VU University Medical Centre in Amsterdam, Netherlands. BioSante’s Prostate cancer vaccine is made from allogeneic prostate cancer cells genetically altered to produce an immune system stimulator called GM-CSF, and irradiated to prevent cell growth. A Phase II GVAX Prostate clinical trial is anticipated to begin in 2012 at the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center.
“We are very excited by the positive results of this prostate cancer study notably combined with recently reported excellent results in pancreatic cancer. This is encouraging news concerning the potential for GVAX cancer vaccines, especially when combined with other anticancer immunotherapies like Ipi, for treatment of a disease that can be so devastating for so many patients,” said Stephen M. Simes, BioSante’s president & chief executive officer.