FK-PC101 Vaccine for High-Risk Prostate Cancer

Inclusion Criteria: * Has localized high-risk or very high-risk prostate cancer based on the NCCN v4.2023 classification. * Has ≥3 prostate biopsy cores with ≥50% tumor involvement. * Has PSA \>4 ng/mL ≤28 days prior to enrollment. * Has no evidence of distant metastases based on PSMA-PET/CT performed ≤28 days prior to enrollment. * Is a candidate for radical prostatectomy, and scheduled radical prostatectomy date must be 3 to 14 days after enrollment. * Has not received nor plans to receive neoadjuvant (preoperative) radiation therapy, androgen deprivation therapy (ADT), or any other anticancer therapy. * Has a life expectancy \>5 years. Additional key eligibility criteria immediately postoperative for inclusion in the randomized population include: * Stage \>pT3a (tumor has extended outside of the prostate on one side). * Gleason score of 8, 9, or 10 (high/very high) on prostatectomy specimen. * Subjects with pT3b or pT4 tumors with a Gleason sum 7 (4+3) are eligible. * Pelvic lymph node dissection (PLND) is required with either pN0 or pN1 nodal staging permitted. * Subjects must have negative surgical margins or microscopic-only positive surgical margins. Final eligibility criteria at 2 months postoperative for randomization include: * FK-PC101 has been produced for the subject and meets all release specifications. * An undetectable PSA (\<0.04 ng/mL) on the most recent test performed prior to randomization (Day -4 to -7). * No prior, current, or planned future postoperative or adjuvant XRT, hormonal therapy such as ADT, or any other anticancer therapy (future therapy should not be administered until evidence exists of prostate cancer disease recurrence \[such as PSA recurrence\]). * Adequate organ function based on CBC and chemistry studies within 2 weeks of Day 1 (Day -14 to -7). Specific laboratory requirements include: * Absolute neutrophil count (ANC) \>1000/µL * Platelet count \>100,000/µL. * Hemoglobin \>8.0 gm/dL. * Estimated glomerular filtration rate (eGFR) \>60 mL/minute based on Cockcroft-Gault formula. * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) both \<2 × upper limit of normal (ULN). * Albumin \>3.0 gm/dL. * Capable of giving signed informed consent, which includes compliance with the requirements and restrictions of the study. Exclusion Criteria: * Has an additional active malignancy that may confound the assessment of the study endpoints. If the subject has a past cancer history (active malignancy within 2 years prior to study entry) with substantial potential for recurrence, this must be discussed with the Sponsor before study entry. Note: Subjects with the following concomitant neoplastic diagnoses are eligible: non-melanoma skin cancer and carcinomas in situ (including breast DCIS, transitional cell carcinoma/NMIBC, anal carcinoma, and melanoma in situ). * Is eligible for and elects to receive adjuvant therapy following RP. * Has clinically significant cardiovascular disease (e.g., uncontrolled or any New York Heart Association \[NYHA\] Class 3 or 4 congestive heart failure, uncontrolled angina, history of myocardial infarction, unstable angina, pulmonary embolism or stroke within 6 months prior to study entry, uncontrolled hypertension, or clinically significant arrhythmias not controlled by medication). * Has uncontrolled, clinically significant pulmonary disease (e.g., chronic obstructive pulmonary disease, pulmonary hypertension) that in the opinion of the Investigator would put the subject at significant risk for pulmonary complications during the study. * Has known metastases, such as bone, visceral, or brain or leptomeningeal metastases. * Has an active autoimmune disease or Grade ≥3 pneumonitis that has required systemic treatment in the past 2 years (i.e., with use of disease-modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) or treatment with drugs (e.g., neomercazol, carbamazole) that function to decrease the generation of thyroid hormone by a hyperfunctioning thyroid gland (e.g., in Graves' disease) is not considered a form of systemic treatment of an autoimmune disease. * Is currently receiving systemic steroid therapy at a prednisone equivalent dose of \>10 mg daily for at least 1 week or other form of immunosuppressive therapy within 7 days prior to enrollment. * Has uncontrolled intercurrent illness including, but not limited to, uncontrolled infection, disseminated intravascular coagulation, or psychiatric illness/social situations that would limit compliance with study requirements. * Is at risk for disseminated BCG infection or has previously demonstrated an allergic response to BCG or its components. * Has known positive status for human immunodeficiency virus (HIV) or active or chronic Hepatitis (Hep) B or Hep C. Screening is not required. * Has any medical condition which in the opinion of the Investigator places the subject at an unacceptably high risk for toxicity.