Platform Study for Prostate Researching Translational Endpoints Correlated to Response to Inform Use of Novel Combinations

Study Overview
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Brief Summary
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This study is designed to evaluate multiple clinical hypotheses and mechanistically-defined combinations to evaluate the safety and efficacy of immunotherapy combinations in participants with mCRPC who have received prior secondary androgen receptor signaling inhibitor therapy (eg, abiraterone, enzalutamide, apalutamide).

Detailed Description
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This is an open-label, non-randomized, exploratory platform protocol designed to assess the safety and antitumor activity of multiple immunotherapy combinations in participants with mCRPC who have received prior therapy. The platform study will consist of 2 stages: Stage 1, an initial stage to evaluate safety, biomarkers, and clinical activity of a combination and Stage 2, an expanded cohort, when warranted, based on the safety, clinical activity, and/or biomarker results from Stage 1. The Sponsor intends to modify and/or add new combinations to the protocol as data emerge from this and other trials. Participants must provide consent for archival tissue from a prior biopsy or surgery for prostate cancer and must consent to baseline and on-treatment biopsies, if medically feasible. Participants will be assigned to receive one of the enrolling combination study interventions and will be monitored for safety and response.

Official Title
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A Multicenter, Open-Label, Exploratory Platform Study to Evaluate Biomarkers and Immunotherapy Combinations for the Treatment of Patients With Metastatic Castration-resistant Prostate Cancer

Conditions
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Metastatic Castration-resistant Prostate Cancer

Intervention / Treatment
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* Drug: NKTR-214 (Cohort A)
* Drug: Nivolumab (Cohort A, B and C)
* Radiation: Stereotactic body radiation therapy (SBRT) (Cohort B)
* Drug: CDX-301 (Cohort B and C)
* Drug: Poly-ICLC (Cohort B)
* Drug: INO-5151 (Cohort C)
* Device: Cellectra 2000


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Metastatic castration resistant prostate cancer with castrate-level testosterone (< 50 ng/dL) at screening. Disease progression per Prostate Cancer Working Group 3 (PCWG3) criteria. Provide fresh pre-treatment core needle or incisional biopsy of a metastatic tumor lesion not previously irradiated. Fine needle aspiration is not acceptable. Additionally, if a pre-treatment biopsy is not medically feasible for participants with bone only disease, formalin-fixed paraffin-embedded (FFPE) tumor specimen in a paraffin block (preferred) or at least 10 slides containing unstained, freshly cut, serial sections must be provided. For all participants, in addition to fresh pre-treatment biopsy, consent for archival tissue is required. Must be willing to undergo tumor biopsy(ies) on treatment, if medically feasible. Have received and progressed on prior secondary androgen receptor signaling inhibitor therapy (eg, abiraterone, enzalutamide, apalutamide). Participants must discontinue antiandrogen therapy (ie, bicalutamide, flutamide, nilutamide) at least 4-6 weeks prior to registration with no evidence of PSA decline after washout. Bicalutamide: Washout period at least 6 weeks Flutamide and nilutamide: Washout period at least 4 weeks Participants must discontinue therapies for mCRPC for 5 half-lives or 28 days, whichever is shorter. Participants will remain on gonadotropin-releasing hormone (GnRH) agents throughout this study. Prior chemotherapy is allowed if no progression of disease on chemotherapy as defined by PCWG3-modified RECIST 1.1. Prior treatment with sipuleucel-T, radium-223, or poly ADP ribose polymerase (PARP) inhibitor (eg, olaparib) is allowed. Tissue biopsy may be performed during washout period. Key Exclusion Criteria: Has a diagnosis of immunodeficiency or conditions that need systemic corticosteroid replacement therapy > 10 mg/day prednisone (or equivalent) or other immunosuppressive medications within 28 days prior to the first dose of study intervention. Inhaled steroids are permitted if necessary. Has any active known or suspected autoimmune disease. Participants with vitiligo, type I diabetes mellitus, controlled autoimmune hypothyroidism, psoriasis not requiring systemic treatment, or other conditions under control are permitted to enroll. Has a known history of active TB (Bacillus Tuberculosis). Has known history of, or any evidence of active, non-infectious pneumonitis. Known history of testing positive for human immunodeficiency virus (HIV), known acquired immunodeficiency syndrome (AIDS), or any positive test for hepatitis B or hepatitis C virus representing acute or chronic disease. Has received a live vaccine within 30 days of planned start of study intervention. Note: Seasonal influenza vaccines for injection are generally inactivated flu vaccines and are allowed; however intranasal influenza vaccines (eg, Flu-Mist®) are live attenuated vaccines, and are not allowed. Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging for at least 4 weeks prior to the first dose of study intervention and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to study intervention. This exception does not include carcinomatous meningitis which is excluded regardless of clinical stability.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cohort A: NKTR-214 + Nivolumab<br> | Drug: NKTR-214 (Cohort A)<br>* NKTR-214 will be administered intravenously every 3 weeks for up to 2 years<br>Drug: Nivolumab (Cohort A, B and C)<br>* Nivolumab will be administered intravenously every 3 weeks for up to 2 years to cohort A, every 4 weeks for up to 2 years for cohort B and C.<br>* Other names: Opdivo;|
| Experimental: Cohort B: SBRT + CDX-301 + Poly-ICLC + Nivolumab<br> | Drug: Nivolumab (Cohort A, B and C)<br>* Nivolumab will be administered intravenously every 3 weeks for up to 2 years to cohort A, every 4 weeks for up to 2 years for cohort B and C.<br>* Other names: Opdivo;Radiation: Stereotactic body radiation therapy (SBRT) (Cohort B)<br>* Radiation therapy will be administered at 30 - 50 Gy in 1 - 5 doses, starting on Day 1 or 2 of Cycle 1<br>Drug: CDX-301 (Cohort B and C)<br>* CDX-301 will be subcutaneously once a day for 5 days for cohort B. CDX-301 will be subcutaneously once a day for 10 days of immune-priming lead-in for cohort C.<br>Drug: Poly-ICLC (Cohort B)<br>* Poly-ICLC will be administered intramuscularly twice weekly for 3 weeks starting on Day 1 of Cycle 1<br>|
| Experimental: Cohort C: CDX-301 + INO-5151 + Nivolumab<br> | Drug: Nivolumab (Cohort A, B and C)<br>* Nivolumab will be administered intravenously every 3 weeks for up to 2 years to cohort A, every 4 weeks for up to 2 years for cohort B and C.<br>* Other names: Opdivo;Drug: CDX-301 (Cohort B and C)<br>* CDX-301 will be subcutaneously once a day for 5 days for cohort B. CDX-301 will be subcutaneously once a day for 10 days of immune-priming lead-in for cohort C.<br>Drug: INO-5151 (Cohort C)<br>* INO-5151 will be administered intramuscularly on Day 8 of the Immune-priming Lead-in, and on day 1 of Cycle 1, 2 and 3, then every 12 weeks thereafter<br>Device: Cellectra 2000<br>* Electroporation device<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence and severity of adverse events |  | Up to 2.5 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Objective response rate (ORR) | ORR is a composite endpoint where response is defined as a participant meeting at least one of the following: circulating tumor cells change from unfavorable to favorable ; ≥ 50% reduction in Prostate-Specific Antigen (PSA) from baseline; confirmed complete response (CR) or partial response (PR) | Up to 2.5 years | 
| Disease control rate | Defined as CR, PR, or stable disease (SD) for 9 months as best response by Prostate Cancer Clinical Trials Working Group 3 (PCWG3)-modified Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 | At 9 months | 
| Radiographic progression-free survival (rPFS) | Defined as time from initiation of study intervention to the first objective evidence of radiographic progression, or death due to any cause (whichever occurs first) | Up to 2.5 years | 
| Overall survival (OS) | Defined as the time from initiation of study invention until death due to any cause | Up to 2.5 years | 
| Overall survival (OS) at 12 months | Defined as the time from initiation of study invention until death due to any cause | At 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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CDX-301, Metastatic Castration-resistant Prostate Cancer, Immunotherapy, Platform study, NKTR-214, Nivolumab, Poly-ICLC, INO-5151