This is a multicenter, randomized, double-blind, placebo-controlled, Phase 2 study of maintenance Vigil Ovarian (gemogenovatucel-T) engineered autologous tumor cells (EATC) in women with Stage IIIb, IIIc or IV high-grade papillary serous/ clear cell / endometrioid ovarian, fallopian tube or primary peritoneal cancer. Subjects will have had a minimum of 4 and a maximum of 12 doses of Vigil prepared and stored from ovarian tumor cells obtained at the time of primary surgical debulking or initial diagnostic / evaluative laparoscopy (tissue for immunotherapy manufacture must be procured prior to initiation of neoadjuvant chemotherapy). An equal number of placebo doses will be manufactured. Subjects will have achieved a clinically defined complete response following primary surgery and adjuvant chemotherapy.