Phase 1 Study to Evaluate the Safety, Feasibility and Immunogenicity of an Allogeneic, Cell-based Vaccine (DCP-001) in High Grade Serous Ovarian Cancer Patients After Primary Treatment

This is a first phase I study in HGSOC patients with primary disease eligible for standard of care treatment with either; complete or optimal primary cytoreductive surgery followed by 6 cycles of adjuvant chemotherapy (carboplatin/paclitaxel); or 3 cycles of neoadjuvant chemotherapy (carboplatin/paclitaxel) followed by complete or optimal cytoreductive interval surgery and 3 additional cycles carboplatin/paclitaxel.

In the current study, DCP-001 vaccinations will be scheduled after standard of care treatment, starting 6 weeks after the last cycle of chemotherapy.

Patients will receive 4 vaccinations containing 25E6 DCP-001 cells per vaccination followed by 2 additional booster vaccinations of 10E6 cells. Each patient will be followed up for 24 months. Safety will be monitored throughout the study. Systemic immune responses are determined by standard immune assays using peripheral blood mononuclear cells (PBMCs) and serum collected before, during and after vaccinations. Progression of disease will be monitored according to standard-of-care follow-up.

Inclusion criteria

• Primary HGSOC patients (FIGO stage 3B to IV) who completed primary treatment defined as:

• primary debulking surgery (complete / optimal) and 6 cycles of adjuvant chemotherapy (carboplatin/paclitaxel)
• 3 cycles of neo-adjuvant chemotherapy (more NACT cycles to improve surgical outcome are allowed) followed by interval debulking surgery (complete / optimal) and 3 cycles of adjuvant chemotherapy (carboplatin/paclitaxel)
• Serum level CA125 < 35 U/mL
• Age ≥ 18 years
• Signed informed consent form (ICF) in accordance with institutional and regulatory guidelines

Exclusion criteria

• History of a second malignancy except for curatively treated low-stage tumors with a histology that can be differentiated from the epithelial OC type
• Patients must have no ongoing or recent evidence (within the last 5 years) of significant autoimmune disease that required treatment with systemic immunosuppressive treatments which may suggest risk for immune-related adverse events (irAEs).

Note: Patients with autoimmune-related hyperthyroidism, autoimmune-related hypothyroidism who are in remission, or on a stable dose of thyroid-replacement hormone, vitiligo, or psoriasis may be included.

• Patients must have no uncontrolled infection with human immunodeficiency virus, hepatitis B or hepatitis C infection; or diagnosis of immunodeficiency that is related to, or results in chronic infection. Mild cancer-related immunodeficiency (such as immunodeficiency treated with gamma globulin and without chronic or recurrent infection) is allowed.

• Patients with known HIV who have controlled infection (undetectable viral load and CD4 count above 350 either spontaneously or on a stable antiviral regimen) are permitted. For patients with controlled HIV infection, monitoring will be performed per local standards.
• Patients with known hepatitis B (HepBsAg+) who have controlled infection (serum hepatitis B virus DNA PCR that is below the limit of detection AND receiving antiviral therapy for hepatitis B) are permitted. Patients with controlled infections must undergo periodic monitoring of HBV DNA per local standards. Patients must remain on anti-viral therapy for at least 6 months beyond the last dose of trial treatment.
• Patients who are known hepatitis C virus antibody positive (HCV Ab+) who have controlled infection (undetectable HCV RNA by PCR either spontaneously or in response to a successful prior course of anti-HCV therapy) are permitted.
• Liver or renal function abnormalities that are considered to be clinically relevant by the investigator.
• Abnormal blood levels (neutropenia among other things) due to chemotherapy that are considered to be clinically relevant by the investigator.

• If so, blood levels will be repeated in 1-2 weeks, in case blood levels are normalized the patient is allowed to be included in the study. In case of persistent abnormal blood levels the patient will be excluded.
• Use of systemic continuous corticosteroid therapy (e.g. prednisone i.v. or p.o. >7.5 mg / day).
• Participation in a trial with another investigational drug within 30 days prior to the enrolment in this trial
• Any condition that in the opinion of the investigator could interfere with the conduct of the trial.