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About
This randomized pilot trial studies vaccine therapy and pembrolizumab in treating patients with prostate cancer that does not respond to treatment with hormones (hormone-resistant) and has spread to other places in the body (metastatic). Vaccines made from deoxyribonucleic acid (DNA), such as pTVG-HP plasmid DNA vaccine, may help the body build an effective immune response to kill tumor cells. Monoclonal antibodies, such as pembrolizumab, may find tumor cells and help kill them. Giving pTVG-HP plasmid DNA vaccine and pembrolizumab may kill more tumor cells.
Full description
PRIMARY OBJECTIVES:
I. To evaluate the safety of pembrolizumab in combination with pTVG-HP (pTVG-HP plasmid DNA vaccine) in patients with castration-resistant, metastatic prostate cancer.
II. To determine the 6-month progression-free survival and median time to radiographic progression in patients with castration-resistant metastatic prostate cancer treated with pembrolizumab in combination with pTVG-HP.
III. To evaluate the anti-tumor response rates (objective response rate and prostate specific antigen [PSA] response rate, using Prostate Cancer Clinical Trials Working Group 2 [PCWG2] criteria) in patients with castration-resistant metastatic prostate cancer treated with pembrolizumab in combination with pTVG-HP.
SECONDARY OBJECTIVES:
I. To determine whether either treatment sequence, or prostatic acid phosphatase (PAP)-specific immune response, is associated with prolonged (6-month) radiographic progression-free survival.
II. To evaluate effects of schedule (concurrent versus delayed administration of pembrolizumab) on the magnitude of PAP-specific T-cell responses, programmed death receptor-1 (PD-1) expression on circulating T cells, and ligands for PD-1 (PD-L1) expression on circulating epithelial cells (CEC) and on tumor biopsies.
III. To determine the median time to radiographic progression using a concurrent administration schedule
TERTIARY OBJECTIVES:
I. To evaluate effects of treatment on number of circulating tumor cells. II. To evaluate PAP-specific antibody responses following treatment with pembrolizumab and pTVG-HP DNA vaccine (pTVG-HP plasmid DNA vaccine).
III. To determine whether either treatment sequence elicits immunologic antigen spread to other prostate-associated antigens.
IV. To determine whether pre-existing or vaccine-induced PD-L1 expression on CEC or tumor biopsies is predictive of objective clinical response.
V. To determine whether treatment elicits expression of other regulatory molecules on tumor-specific T cells (e.g. hepatitis A virus cellular receptor 2 [TIM3], B and T lymphocyte associated [BTLA], and lymphocyte-activation gene 3 [LAG3]) or tumor cells (e.g. tumor necrosis factor receptor superfamily, member 14 [HVEM], phosphatidyl serine, ligands for programmed death receptor-2 [PD-2] [PD-L2]).
VI. To determine whether PD-1-regulated antigen-specific T cells identified by trans vivo delayed-type hypersensitivity (DTH) testing can identify patients who develop objective clinical responses with PD-1 blockade therapy in combination with pTVG-HP.
VII. To determine whether changes in lymph nodes and soft tissue tumor lesions are observed by fluorothymidine F-18 (FLT) positron emission tomography (PET)/computed tomography (CT) after treatment with vaccine with or without pembrolizumab.
VIII. To determine if PD-1 inhibitor therapy in combination with pTVG-HP will change number and activity (SUV) in osteoblastic metastases as measured by NaF PET/CT.
OUTLINE: Patients are randomized to 1 of 2 treatment arms.
ARM I: Patients receive pTVG-HP plasmid DNA vaccine intradermally (ID) every other week on days 1, 15, 29, 43, 57, and 71 and pembrolizumab intravenously (IV) over 30 minutes every 3 weeks on days 1, 22, 43, and 64.
ARM II: Patients receive pTVG-HP plasmid DNA vaccine ID as in Arm I and pembrolizumab IV over 30 minutes every 3 weeks on days 85, 106, 127, and 148.
After completion of study treatment, patients are followed up 3, 6, 9, and 12 months and then annually for 2 years.
ARM III: Extended Treatment. Patients received pTVG-HP + Pembrolizumab Extended Treatment
ARM IV: Extended Treatment. Patients receive pTVG-HP every two weeks, and Pembrolizumab every 4 weeks
Enrollment
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Volunteers
Inclusion criteria
Histologically confirmed diagnosis of prostate cancer (adenocarcinoma of the prostate)
Metastatic disease as evidenced by the presence of soft tissue and/or bone metastases on imaging studies (CT of abdomen/pelvis, bone scintigraphy)
Castrate-resistant disease, defined as follows:
Progressive disease while receiving androgen deprivation therapy defined by any one of the following as per the Prostate Cancer Clinical Trials Working Group 2 (PCWG2) bone scan criteria or Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 during or after completing last therapy:
Prior treatment with abiraterone or enzalutamide is permitted, but patients must have been off prior corticosteroid treatment for at least 3 months
Life expectancy of at least 6 months
Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2
White blood cells (WBC) >= 2000/mm^3
Absolute neutrophil count (ANC) >= 1000/mm^3
Hemoglobin (HgB) >= 9.0 gm/dL
Platelets >= 100,000/mm^3
Creatinine =< 2.0 mg/dL
Aspartate aminotransferase (AST), alanine aminotransferase (ALT) =< 2.5 x institutional upper limit of normal
No known history of human immunodeficiency virus (HIV) 1 and 2, human T-lymphotropic virus (HTLV)-1, or active hepatitis B or hepatitis C
Patients must be at least 4 weeks from any prior treatments and have recovered (to < grade 2) from acute toxicity attributed to this prior treatment, unless considered chronic
Patients must be willing and able (in the opinion of the treating physician) to undergo two research biopsies for the investigational component of this trial
Patients must be willing to undergo two leukapheresis procedures for the investigational component of this trial
Patients must be willing to undergo FLT PET/CT or NaF PET/CT scans for the investigational component of this trial and have no known allergies to FLT or NaF
For those patients who are sexually active, they must be willing to use barrier contraceptive methods during the period of treatment on this trial (and for four weeks after the last DNA immunization treatment for patients in Arm 1)
Patients must be informed of the experimental nature of the study and its potential risks, and must sign an Institutional Review Board (IRB)-approved written informed consent form indicating such an understanding
Exclusion criteria
Small cell or other variant (non-adenocarcinoma) prostate cancer histology, unless there is evidence that the tumor expresses PAP
Patients may not be receiving other investigational agents or be receiving concurrent anticancer therapy other than standard androgen deprivation therapy
Concurrent bisphosphonate therapy is not excluded, however patients should not start bisphosphonate therapy while on this study; those patients already receiving bisphosphonate therapy should continue at the same dosing and schedule as prior to study entry
Rapidly progressive symptomatic metastatic disease, as defined by the need for increased opioid analgesics within one month of registration for the treatment of pain attributed to a prostate cancer metastatic lesion; patients receiving opioids must receive approval from the principal investigator (PI) for eligibility
Treatment with any of the following medications within 28 days of registration, or while on study, is prohibited:
External beam radiation therapy within 4 weeks of registration is prohibited, or anticipated need for radiation therapy (e.g. imminent pathological fracture or spinal cord compression) within 3 months of registration
Major surgery within 4 weeks of registration is prohibited
Prior cytotoxic chemotherapy (for example, but not limited to, docetaxel, mitoxantrone, cabazitaxel) within 6 months of registration is prohibited
Patients with a history of life-threatening autoimmune disease
Patients with a history of allergic reactions to filgrastim (GM-CSF) or the tetanus vaccine
Patients who have undergone splenectomy
Patients must not have other active malignancies other than non-melanoma skin cancers or superficial bladder cancer; subjects with a history of other cancers who have been adequately treated and have been recurrence-free for >= 3 years are eligible
Patients with known brain metastases
Any antibiotic therapy or evidence of infection within 1 week of registration
Any other medical intervention or condition, which, in the opinion of the PI or treating physician, could compromise patient safety or adherence with the study requirements (including biopsies or leukapheresis procedures) over the primary 3-6 month treatment period
Patients cannot have concurrent enrollment on other phase I, II, or III investigational treatment studies
NOTE: There is no exclusion for prior immune-based therapy. This includes patients previously treated on Arms 1 or 2 who are otherwise eligible for treatment on Arm 3 or 4.
Primary purpose
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Interventional model
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66 participants in 4 patient groups
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Data sourced from clinicaltrials.gov
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