Polyvalent vaccine-KLH conjugate and OPT-821 with bevacizumab (BEV) in patients with ovarian cancer in second or greater remission.
5550 Background: We previously completed a phase I study of a polyvalent vaccine containing GM2, Globo-H, LeY, Tn-MUC1, Tn(c), STn(c) and TF(c) antigens (AGs) individually conjugated to KLH and mixed with adjuvant OPT-821. We showed safe induction of antibody (ab) responses to 5 of the 7 vaccine AGs. Data has shown that tumor vaccine efficacy may be enhanced through disruption of angiogenesis thus providing a rationale for combining BEV with the polyvalent vaccine. We conducted an IRB-approved pilot study to evaluate the safety and immunogenicity of the poly-KLH-vaccine when given with BEV in OC in remission. Methods: Pts with recurrent OC in ≥2nd complete or partial remission were enrolled from 12/2010-03/2012. Pts received 6 vaccines and BEV over 17 weeks. BEV was continued beyond the vaccination phase. Treatment was continued until disease progression or toxicity. Serologic IgM and IgG responses were measured by ELISA against each AG. Wilcoxon signed rank test was used to test changes in cytokines (CKs): FGFβ, IL-8, PDGF, VEGF measured by angio multiplex assay. Results: n=21 Median age 56yrs (51-70). 2, 8, 8, 3 pts were in 2nd, 3rd, 4th, 5th remission, respectively. 1 DLT (gr 4 fever post vaccine #2). Immune Results: n=19 IgG +/or IgM: ≥3 AGs in 17pts. IgM: ≥1 AG in 19pts, ≥3 AGs in 15pts. IgG: ≥1 AG in 17pts, ≥3 AGs in 3pts. CK Results: In 10 pts who completed 6 vaccines there was a mean (median) decrease in VEGF of 144 (111) pg/ml at the 17-week timepoint compared to baseline (p=0.05). For 8 pts who did not complete all 6 vaccines there was a mean (median) increase of 76 (69) pg/ml compared to baseline at the off-study visit (p=0.16). There was no statistically significant change in the other CKs compared to baseline values. At last follow-up, 18 pts had recurred and 3 pts had died. The median PFS was 5.6mths. Conclusions: 89% of pts responded to ≥3 AGs comparable to the 89% response in our prior phase I trial without BEV. BEV and polyvalent-KLH vaccine can be safely administered together with retention of the vaccine’s immunogenicity. Serum VEGF levels decreased in patients on continued BEV therapy. Clinical trial information: NCT01223235. [Table: see text]