Inclusion Criteria

1. Female patient ≥ 18 years
2. Willing and able to give informed consent
3. Stage III-IV platinum-sensitive (defined as a lack of progression by RECIST v1.1 criteria following completion of standard-of-care chemotherapy, including a minimum of 4 cycles of a platinum-containing regimen) epithelial ovarian, fallopian tube or primary peritoneal carcinoma in first remission.
4. Histologic documentation of diagnosis of carcinoma is required and the following histologic subtypes are eligible: high grade (grade ≥3+) serous or endometrioid carcinoma, carcinosarcoma, or poorly-differentiated adenocarcinoma, or mixed (including above subtypes only). Note that synchronous serous or endometrioid uterine or fallopian cancers are allowed.
5. The patient must have demonstrated an objective response (PR or CR) or stable disease (SD) with the last chemotherapy prior to enrollment and this response must be stable (without progressive disease) before randomization.
6. Patients must receive their first dose of vaccine within 1 year of completion of their final dose of a chemotherapeutic agent of the platinum-containing regimen
7. Adequate normal organ and marrow function within 14 days prior to first vaccine administration:
   • Absolute neutrophil count > 1.5 x 109/L
   • Platelet > 100 x 109/L
   • Hemoglobin > 9.0 g/dL
   • Serum bilirubin < 1.5 times ULN (unless Gilbert's syndrome without concurrent clinically significant liver disease
   • AST/ALT < 2.5 ULN unless liver metastasis in which case it must be < 5 x ULN
   • Serum creatinine CL > 40 mL/min by Cockcroft-Gault formula.
8. Anti-nuclear antibody (ANA) negative or low-positive institutional range, as determined within 28 days from registration. Intermediate values (usually defined by a titer of ≤1:80, or as indicated by institutional range) are acceptable if there are, in the opinion of the Investigator, no early signs of an autoimmune disease.
9. Female subjects must either be of non-reproductive potential (i.e. post-menopause by history: > 60 years old and no menses for > 12 months naturally or secondary to radiation/chemotherapy; OR serum FSH, LH and estradiol levels in the post-menopausal range; OR history of hysterectomy; OR history of bilateral tubal ligation; OR history of bilateral oophorectomy), or must have a negative serum pregnancy test upon study entry
10. Life expectancy > 24 weeks
11. ECOG performance status of 0 or 1
12. Formalin fixed, paraffin embedded tumor sample from the primary cancer must be sent for central testing.

Exclusion Criteria

1. Histology consistent with non-serous, non-endometrioid (i.e. mucinous or clear cell), or low-grade or borderline serous ovarian carcinoma
2. Patients with a history of other cancers (other than non-melanoma skin cancers [i.e. basal or squamous cell]) within the past 3 years.
3. Receipt of the last dose of anti-cancer therapy (chemotherapy, immunotherapy, targeted therapy, biological/cell therapy, tumor embolization, monoclonal antibodies, other investigational agent) < 28 days prior to the first dose of study drug.
4. Current or prior use of immunosuppressive medication within 28 days prior to the fist dose of study drug with the exception of topical, intranasal or inhaled corticosteroids or systemic corticosteroids at physiological doses, which are not to exceed 10 mg/day of prednisone, or an equivalent corticosteroid.
5. Active autoimmune disease requiring therapy within the past 2 years. Note: patients with vitiligo, Grave's disease or psoriasis not requiring systemic treatment within the past 2 years are not excluded.
6. History of hypersensitivity to GM-CSF
7. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable angina pectoris, cardiac arrhythmia, active peptic ulcer disease or gastritis, active bleeding diatheses including any subject known to have evidence of acute or chronic hepatitis B, hepatitis C or human immunodeficiency virus (HIV), or psychiatric illness/social situations that would limit compliance with study requirements or compromise the ability of the subject to give written informed consent
8. Symptomatic thyroid disease, unless negative for thyroid antibodies (TSH receptor, TPO, thyroglobulin).
9. Subjects who are pregnant or are breast feeding.
10. Subjects who or of reproductive potential, and are either:
    • Not abstinent
    • Not in an exclusive relationship with a partner who is surgically sterile
    • Not employing an effective method of birth control
11. Any condition that, in the opinion of the investigator, would interfere with evaluation of study treatment or interpretation of patient safety or study results
12. Symptomatic or uncontrolled brain metastasis requiring concurrent treatment, inclusive of but not limited to surgery, radiation and/or corticosteroids
13. Subject with uncontrolled seizures