Galena Tests Ovarian Cancer Vaccine

Galena Biopharma presented Phase I data at a poster presentation at the Society for Immunotherapy of Cancer (SITC) Conference 2013 on November 7-10, 2013. The data presented are the results of the Phase I portion of the trial for the Folate Binding Protein (FBP) vaccine. FBP is a folate receptor alpha-derived, peptide-based cancer immunotherapy administered to HLA A2 positive patients in combination with granulocyte macrophage-colony stimulating factor (GM-CSF) as an adjuvant treatment to prevent recurrences in high-risk, endometrial and ovarian cancer patients rendered disease-free after completing standard of care therapy.

The poster presentation, “Phase 1 Trial Results of a Folate Receptor Alpha-directed Cancer Vaccine (E39) in Ovarian and Endometrial Cancer Patients to Prevent Recurrence,” showed that the FBP vaccine is both safe and immunogenic. The primary outcome of the trial was to determine safety and the optimal dose, with a secondary outcome to look for an initial efficacy signal and immunological response. The optimal dose was determined to be 500 mcg peptide combined with 250 mcg GM-CSF. FBP proved to be well tolerated, with largely Grade 1 toxicities, primarily consisting of injection site reactions. After a median follow-up of six months, there have been two recurrences (13.3%; n=15) in the vaccine group vs. four recurrences (25%, n=16) in the control group, although the trial was not powered for any efficacy measurements.

The Phase I component of the trial was a 3×3, dose-escalation, safety trial enrolling disease-free endometrial and ovarian cancer, HLA-A2 positive patients into the vaccine group, while HLA-A2 negative patients were being followed prospectively as an untreated control group. Six monthly intradermal inoculations of either 100mcg, 500mcg, or 1000mcg of peptide vaccine + 250 mcg GM-CSF immunoadjuvant were administered during the primary vaccine series. Immunologic responses were assessed by both local reaction after each inoculation and by delayed-type hypersensitivity (DTH) reaction measured pre-vaccination and after the primary vaccine series. Recurrences are determined clinically. Thirty-one patients were enrolled in the Phase I trial: 15 in the vaccine group and 16 in the active control group. There were no significant differences in age, grade, stage, or nodal status between groups. Overall, the vaccine was well tolerated with the majority of local and systemic toxicities Grade 1 (maximum local toxicity: 93% Grade 1; maximum systemic toxicity: 60% Grade 1). Local skin reactions increased from the first to the third injections, and then plateaued for the remainder of therapy.

The company is moving forward with the Phase IIa component of the study, which will be initiated by the end of 2013 and will include the enrollment of additional patients at the optimal dose as well implementing a booster regimen.