Pembrolizumab +/- SD-101 in Hormone-Naïve Oligometastatic Prostate Cancer With RT and iADT

NCT ID: NCT03007732

Last Updated: 2025-12-05

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE2
• Total Enrollment: 23 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-05-17
• Study Completion Date: 2025-03-31

Brief Summary

This is a non-comparative open-label multicenter Phase 2 clinical trial combining stereotactic body radiation therapy (SBRT) and pembrolizumab with or without intratumoral SD-101 in participants with newly diagnosed hormone-naive oligometastatic prostate cancer.

Detailed Description

This randomized phase II trial studies how well androgen deprivation therapy, pembrolizumab, and stereotactic body radiation therapy with or without toll-like receptor 9 (TLR9) agonist SD-101 in treating participants with prostate cancer and cancer in all oligometastatic sites that has spread to other places in the body. Androgen can cause the growth of tumor cells. Androgen deprivation therapy, such as leuprolide acetate, prednisone, and abiraterone acetate may lessen the amount of androgen made by the body. Monoclonal antibodies, such as pembrolizumab, may interfere with the ability of tumor cells to grow and spread. Stereotactic body radiation therapy is a specialized radiation therapy that sends x-rays directly to the tumor using smaller doses over several days and may cause less damage to normal tissue. Colony-stimulating factors, such as TLR9 agonist SD-101, may increase the production of blood cells. It is not yet known whether giving androgen deprivation therapy, pembrolizumab, and stereotactic body radiation therapy with or without TLR9 agonist SD-101 may work better in treating participants with prostate cancer and cancer in all oligometastatic sites.

PRIMARY OBJECTIVES

COHORT 1:

-- To assess the safety associated with giving RT and pembrolizumab with or without intratumoral SD-101.

COHORT 2:

• To continue to assess the safety associated with giving RT and pembrolizumab with or without intratumoral SD-101.
• To assess if the rate of PSA < nadir + 2 ng/mL at 15 months in participants with non-castrate levels of testosterone is greater than the historical control in each study arm.

SECONDARY OBJECTIVES

COHORT 2 ONLY:

• To determine the rate of testosterone-prostate specific antigen (PSA) uncoupling in each study arm in Cohort 2. Testosterone-PSA uncoupling is defined as PSA < 50% baseline and < 20ng/mL for at least 3 months after testosterone recovers to >150 ng/dL. In participants with metastatic hormone sensitive prostate cancer off hormonal therapy, >90% of participants are expected to have PSA increase to > 50% baseline after 3 months of testosterone recovery.
• To estimate time to clinical progression in each study arm in Cohort 2.
• To estimate progression-free survival (PFS) in each study arm Cohort 2.

EXPLORATORY OBJECTIVE

• To assess peripheral and tumor-based biomarkers of response and resistance in both cohorts.
• To define the treatment-induced effects on circulating immune cells in both cohorts.
• To explore remodeling of circulating T cell repertoire in both cohorts.
• To explore the concordance of Prostate-Specific Membrane Antigen (PSMA) - Positron Emission Tomography (PET) scanning with conventional imaging in oligometastatic prostate cancer participants in both cohorts.

Conditions

Prostatic Neoplasms

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Cohort 1, Arm 1: Prostate Only Sites (ADT, SBRT, Pembrolizumab)

Three month androgen deprivation therapy (ADT) run-in followed by leuprolide injected intramuscularly every 3 months for 3 doses (or another FDA approved gonadotropin-releasing hormone agent for 9 months) + abiraterone by mouth daily with prednisone by mouth daily (or equivalent medication per local standard practice) for 9 months starting on Day 1.

Pembrolizumab: Given IV every 21 days for up to 13 doses

Radiotherapy: Given every other day over 10-14 days delivered to the whole prostate gland via stereotactic body radiation therapy (SBRT) starting 1-2 weeks after marker placement.

Group Type: EXPERIMENTAL

No interventions assigned to this group

Cohort 1, Arm 2: Prostate Only Sites (ADT, SBRT, Pembrolizumab, SD-101)

Three month androgen deprivation therapy (ADT) run-in followed by leuprolide injected intramuscularly every 3 months for 3 doses (or another FDA approved gonadotropin-releasing hormone agent for 9 months) + abiraterone by mouth daily with prednisone by mouth daily (or equivalent medication per local standard practice) for 9 months starting on Day 1.

TLR9 agonist SD-101: Injected into the dominant prostatic tumor lesion at time of fiducial marker placement (1-5weeks prior to Cycle 1 Day 1) and 1-3 weeks after Cycle 1 Day 1

Pembrolizumab: Given IV every 21 days for up to 13 doses

Radiotherapy: Given every other day over 10-14 days delivered to the whole prostate gland via stereotactic body radiation therapy (SBRT) starting 1-2 weeks after marker placement.

Group Type: EXPERIMENTAL

No interventions assigned to this group

Cohort 2, Arm 1: Prostate and Oligometastatic sites (ADT, SBRT, Pembrolizumab)

Three month androgen deprivation therapy (ADT) run-in followed by leuprolide injected intramuscularly every 3 months for 3 doses (or another FDA approved gonadotropin-releasing hormone agent for 9 months) + abiraterone by mouth daily with prednisone by mouth daily (or equivalent medication per local standard practice) for 9 months starting on Day 1.

Pembrolizumab: Given IV every 21 days for up to 13 doses

Radiotherapy: Given every other day over 10-14 days delivered to the whole prostate gland and oligometastatic sites via stereotactic body radiation therapy (SBRT) starting 1-2 weeks after marker placement.

Group Type: EXPERIMENTAL

Pembrolizumab

Intervention Type: DRUG

200 mg IV every 21 days for up to 13 doses (Arms 1 and 2)

Leuprolide acetate

Intervention Type: DRUG

22.5 mg will be given intramuscularly (IM). First injection 3 months prior to Cycle 1 Day 1. Intermittent androgen deprivation therapy will be given every 3 months starting Cycle 1, Day 1 for 3 additional doses.

Abiraterone Acetate

Intervention Type: DRUG

1000 mg oral dosage will be given daily for 3 months prior to Cycle 1, Day 1 and daily for 9 months starting Cycle 1, Day 1.

Prednisone

Intervention Type: DRUG

5 mg oral dosage will be given daily for 3 months prior to Cycle 1 Day 1 and daily for 9 months starting Cycle 1, Day 1.

Stereotactic Body Radiation Therapy

Intervention Type: RADIATION

7 Gy x 5 fractions (35 Gy total) 1-2 weeks after fiducial marker placement and simulation over 10-14 days.

Cohort 2, Arm 2: Prostate and Oligometastatic sites (ADT, SBRT, Pembrolizumab, SD-101)

Three month androgen deprivation therapy (ADT) run-in followed by leuprolide injected intramuscularly every 3 months for 3 doses (or another FDA approved gonadotropin-releasing hormone agent for 9 months) + abiraterone by mouth daily with prednisone by mouth daily (or equivalent medication per local standard practice) for 9 months starting on Day 1.

TLR9 agonist SD-101: Injected into the dominant prostatic tumor lesion at time of fiducial marker placement (1-5weeks prior to Cycle 1 Day 1) and 1-3 weeks after Cycle 1 Day 1

Pembrolizumab: Given IV every 21 days for up to 13 doses

Radiotherapy: Given every other day over 10-14 days delivered to the whole prostate gland and oligometastatic sites via stereotactic body radiation therapy (SBRT) starting 1-2 weeks after marker placement.

Group Type: EXPERIMENTAL

Pembrolizumab

Intervention Type: DRUG

200 mg IV every 21 days for up to 13 doses (Arms 1 and 2)

SD-101

Intervention Type: DRUG

5 mg will be delivered to the dominant prostatic tumor lesion at time of fiducial marker placement (1-5 weeks prior to Cycle 1, Day 1) and and 1-3 weeks after Cycle 1 Day 1

Leuprolide acetate

Intervention Type: DRUG

22.5 mg will be given intramuscularly (IM). First injection 3 months prior to Cycle 1 Day 1. Intermittent androgen deprivation therapy will be given every 3 months starting Cycle 1, Day 1 for 3 additional doses.

Abiraterone Acetate

Intervention Type: DRUG

1000 mg oral dosage will be given daily for 3 months prior to Cycle 1, Day 1 and daily for 9 months starting Cycle 1, Day 1.

Prednisone

Intervention Type: DRUG

5 mg oral dosage will be given daily for 3 months prior to Cycle 1 Day 1 and daily for 9 months starting Cycle 1, Day 1.

Stereotactic Body Radiation Therapy

Intervention Type: RADIATION

7 Gy x 5 fractions (35 Gy total) 1-2 weeks after fiducial marker placement and simulation over 10-14 days.

Interventions

Pembrolizumab

200 mg IV every 21 days for up to 13 doses (Arms 1 and 2)

Intervention Type: DRUG

SD-101

5 mg will be delivered to the dominant prostatic tumor lesion at time of fiducial marker placement (1-5 weeks prior to Cycle 1, Day 1) and and 1-3 weeks after Cycle 1 Day 1

Intervention Type: DRUG

Leuprolide acetate

22.5 mg will be given intramuscularly (IM). First injection 3 months prior to Cycle 1 Day 1. Intermittent androgen deprivation therapy will be given every 3 months starting Cycle 1, Day 1 for 3 additional doses.

Intervention Type: DRUG

Abiraterone Acetate

1000 mg oral dosage will be given daily for 3 months prior to Cycle 1, Day 1 and daily for 9 months starting Cycle 1, Day 1.

Intervention Type: DRUG

Prednisone

5 mg oral dosage will be given daily for 3 months prior to Cycle 1 Day 1 and daily for 9 months starting Cycle 1, Day 1.

Intervention Type: DRUG

Stereotactic Body Radiation Therapy

7 Gy x 5 fractions (35 Gy total) 1-2 weeks after fiducial marker placement and simulation over 10-14 days.

Intervention Type: RADIATION

Other Intervention Names

MK-3475; Keytruda; Toll-like receptor 9; Intermittent androgen deprivation therapy; Intermittent androgen deprivation therapy; Intermittent androgen deprivation therapy; SBRT

Eligibility Criteria

Inclusion Criteria

1. Be willing and able to provide written informed consent/assent for the trial.

2. Be >=18 years of age on day of signing informed consent.

3. Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale.

4. Histologically documented adenocarcinoma of the prostate

5. Oligometastatic disease. In order to be eligible, the participant must have a total of <4 metastatic bone and/or metastatic lymph node sites based on bone and/or soft tissue lesions as defined by any of the following:

1. Bone metastases will be defined by bone imaging. If the participant has technetium bone scan, and/or sodium fluoride (NaF) PET performed, either study may be used for documenting metastases; both scans do not need to show the number of metastases required for study entry. For participants undergoing PSMA PET, only PSMA avid lesions that are consistent with metastasis will be counted as a site of metastasis.

2. Distant metastatic lymph node disease. A lymph node ≥1 cm in shortest dimension will be noted as involved with disease. Distant metastatic lymph nodes will be determined as any lymph nodes outside the confines of the true pelvis. For participants undergoing PSMA PET, only PSMA avid lesions that are consistent with metastasis will be counted as a site of metastasis.

3. Any other soft tissue lesion deemed by the physician to be consistent with distant metastatic disease. For participants undergoing PSMA PET, only PSMA avid lesions that have a CT or MRI correlate consistent with metastasis will be counted as a site of metastasis.

• Note: Radiographic imaging performed as standard of care prior to obtaining informed consent and within 60 days of initiating study treatment may be used to assess oligometastatic disease during screening, rather than repeating scans. For participants who have started on ADT, they must have had imaging prior to initiation of hormonal therapy

6. Treatment naïve, defined as less than 2 months of standard of care ADT (e.g. GnRH agonist or antagonist with or without antiandrogen, including abiraterone) for metastatic hormone-sensitive prostate cancer prior to enrollment (at the time of consent)

7. No prior chemotherapy for prostate cancer

8. Not a candidate for or refuse chemotherapy

9. No prior prostatectomy or prostatic radiation

10. PSA >2 ng/mL at baseline or prior to initiation of hormonal therapy

11. Baseline testosterone >150 ng/dL if participant has not initiated hormonal therapy, for those participants who have already initiated hormonal therapy, baseline testosterone is not required

12. Consent to undergo mandatory prostatic core biopsies at the time of fiducial marker placement and 1-3 weeks after Cycle 1 Day 1 of pembrolizumab.

13. The effects of pembrolizumab on the developing human fetus is unknown. Men treated or enrolled on this protocol must agree to use adequate contraception prior to the first dose of study therapy, for the duration of the study participation, and for 120 days after the last dose of study therapy. Their partners should also be encouraged to use proper method of contraception. Their partners should also be encouraged to use proper method of contraception.

14. Demonstrate adequate organ function defined as: Adequate Organ Function Laboratory Values (Performed within 10 days of treatment initiation):

• Absolute neutrophil count (ANC) ≥1,500 /microliter (mcL)
• Platelets >=100,000 / mcL
• Hemoglobin >=9 g/dL or ≥5.6 mmol/L without transfusion or erythropoietin (EPO) dependency (within 7 days of assessment)
• Serum creatinine OR Measured or calculated creatinine clearance (GFR can also be used in place of creatinine or CrCl) <=1.5 X upper limit of normal (ULN) OR ≥60 mL/min for subject with creatinine levels > 1.5 X institutional ULN. Creatinine clearance should be calculated per institutional standard
• Serum total bilirubin <= 1.5 X ULN OR Direct bilirubin <= ULN for subjects with total bilirubin levels > 1.5 ULN
• Aspartate aminotransferase (AST) (SGOT) and alanine aminotransferase (ALT) (SGPT) ≤ 2.5 X ULN OR ≤ 5 X ULN for subjects with liver metastases
• Albumin >2.5 mg/dL
• International Normalized Ratio (INR) or Prothrombin Time (PT)
• Activated Partial Thromboplastin Time (aPTT) ≤1.5 X ULN unless subject is receiving anticoagulant therapy as long as PT or PTT is within therapeutic range of intended use of anticoagulants ≤1.5 X ULN unless subject is receiving anticoagulant therapy as long as PT or PTT is within therapeutic range of intended use of anticoagulants
• Creatinine clearance should be calculated per institutional standard.

Exclusion Criteria

1. Participants who are not appropriate candidates for prostate or oligometastasis-directed SBRT

2. Participants with neuroendocrine or small cell features are not eligible.

3. Participants with evidence of liver metastasis are excluded.

4. Gonadotropin-releasing hormone (GnRH) agonists or GnRH antagonists (e.g., leuprorelin, degarelix) for > 2 months prior to consenting

5. Antiandrogens (e.g., bicalutamide, flutamide, nilutamide, abiraterone, enzalutamide) for > 2 months prior to consenting. Participants on 5-alpha reductase inhibitors are allowed on study.

6. Estrogen containing compounds for > 2 months prior to consenting

7. PC-SPES or PC-x products. Other herbal therapies or supplements will be considered by the Principle Investigator on a case-by-case basis based on their potential for hormonal or anti-cancer therapies.

8. Prior immunotherapy or chemotherapy for prostate cancer

9. Prior radiation therapy to the prostate

10. Prior prostatectomy

11. Is currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 4 weeks of the first dose of treatment.

12. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of systemic immunosuppressive therapy within 7 days prior to the first dose of trial treatment, with the exception of steroids for adrenal insufficiency in which case prednisone =<10mg/day or its equivalent is allowed.

13. Has a known history of active Bacillus Tuberculosis (TB)

14. Hypersensitivity to pembrolizumab or any of its excipients.

15. Has had a prior anti-cancer monoclonal antibody (mAb) within 4 weeks prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events due to agents administered more than 4 weeks earlier.

16. Has had prior chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events due to a previously administered agent.

• Note: Subjects with <= Grade 2 neuropathy are an exception to this criterion and may qualify for the study.
• Note: If subject received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting

17. Has a known additional malignancy that is progressing or requires active treatment. Exceptions include carcinoid, basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer.

18. Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis. Subjects with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging for at least four weeks prior to the first dose of trial treatment and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and are not using steroid treatment for at least 14 days prior to the first dose of study treatment. This exception does not include carcinomatous meningitis which is excluded regardless of clinical stability.

19. Has active autoimmune disease 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, etc.) is not considered a form of systemic treatment.

20. Has known history of, or any evidence of active, non-infectious pneumonitis.

21. Has an active infection requiring systemic therapy.

22. Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the subject's participation for the full duration of the trial, or is not in the best interest of the subject to participate, in the opinion of the treating investigator.

23. Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.

24. Expecting to father children within the projected duration of the trial, starting with the pre-screening or screening visit through 120 days after the last dose of trial treatment.

25. Has received prior therapy with an anti-programmed cell death protein 1 (PD-1), anti-programmed death-ligand 1 (PD-L1) , or anti-Programmed cell death 1 ligand 2 (PD-L2) agent.

26. Has a known history of Human Immunodeficiency Virus (HIV) (HIV 1/2 antibodies).

27. Has known active Hepatitis B (e.g., HBsAg reactive) or Hepatitis C (HCV) (i.e. HCV RNA [qualitative] is detected).

28. Has received a live vaccine within 30 days of planned start of study therapy. a. Note: Seasonal influenza vaccines for injection are generally inactivated flu vaccines and are allowed; however intranasal influenza vaccines (e.g., Flu-Mist®) are live attenuated vaccines, and are not allowed within 30 days.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Prostate Cancer Foundation

OTHER

Sponsor Role: collaborator

Merck Sharp & Dohme LLC

INDUSTRY

Sponsor Role: collaborator

TriSalus Life Sciences, Inc.

INDUSTRY

Sponsor Role: collaborator

David Oh

OTHER

Sponsor Role: lead

Responsible Party

David Oh

Assistant Professor

Responsibility Role: SPONSOR_INVESTIGATOR

Principal Investigators

David Oh, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

University of California, San Francisco

Locations

University of California San Francisco

San Francisco, California, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

NCI-2017-01340

Identifier Type: REGISTRY

Identifier Source: secondary_id

16703

Identifier Type: -

Identifier Source: org_study_id