Phase I trial of NY-ESO-1/LAGE1 peptide vaccine for metastatic castration resistant prostate cancer (mCRPC).

4643 Background: The NY-ESO-1 and LAGE-1 antigens are amplified in malignancies including prostate cancer. Preclinical induction of immune responses and anti-tumor activity has been demonstrated upon administration of these peptides. A phase I/II clinical trial evaluated the feasibility of a combined HLA class-I and class-II peptide vaccine in mCRPC. Methods: Men with progressive mCRPC, Performance Status ≤2, PSA ≥10 ng/ml and had appropriate HLA class I (A2) and class II haplotypes (DR4, DP4, DR13) were eligible. Three groups with 3 patients each received the vaccine subcutaneously every 2 weeks for 6 doses. Group 1 was treated with a peptide directed at a HLA class I haplotype (HLA A2), Group 2 was treated with a peptide reacting to a HLA class II haplotype (DR4, DP4, or DR13), and Group 3 received peptides directed at both Class I and II haplotypes. Group I and Group II received 1 dose of 1000 mcg and Group III received doses of 1000 mcg for each of 2 peptides. Androgen-deprivation was continued. Resul...