For Healthcare Professionals

A Trial of BXCL701 and Pembrolizumab in Patients With mCRPC Either Small Cell Neuroendocrine Prostate Cancer or Adenocarcinoma Phenotype.


About the study

An open-label, multicenter, Phase 1b/2 study to identify the recommended Phase 2 dose and assess the efficacy and safety of BXCL701 administered orally, as monotherapy and in combination with PEMBRO, in patients with mCRPC. Patients enrolled in the Phase 2a portion of the study will have either Small Cell Neuroendocrine Prostate Cancer(SCNC)(Cohort A) or adenocarcinoma phenotype (Cohort B), while the Phase 2b randomized portion of the study will enroll only the histologic subtype(s) showing preliminary evidence in Phase 2a. The study will also assess other efficacy parameters, such as rPFS, PSA PFS, OS, and DOR, as well as the safety of the combined treatment. The study will consist of three components.

Who can take part

You may be eligible to participate in the study if you meet the following criteria:



    1. Patient has received treatment with >2 cytotoxic chemotherapy regimens for castration-resistant prostate cancer (CRPC). Chemotherapy in the hormone-sensitive setting does not count in this assessment provided the last dose was >6 months before study entry. A change in chemotherapy agents due to intolerance after brief exposure may not count in this assessment, pending review with Medical Monitor.
    2. Patient has received external-beam radiation or another systemic anticancer therapy within 14 days or 5 half-lives, whichever is shorter, prior to study treatment.
    3. Patient has received treatment with an investigational systemic anticancer agent within 14 days prior to study drug administration.
    4. Patient has received prior treatment with an anti-PD-1, anti-PD-L1, anti-programmed death ligand 2 (PD-L2) agent or with an agent directed to another co-inhibitory T-cell receptor (e.g., cytotoxic T lymphocyte-associated antigen 4 [CTLA-4], OX-40, CD137) or requires concomitant treatment with DPP4 inhibitors.
    5. Patient has an additional active malignancy that may confound the assessment of the study endpoints. If the patient 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. Patients with the following concomitant neoplastic diagnoses are eligible: non-melanoma skin cancer and carcinomas in situ (including transitional cell carcinoma, anal carcinoma, and melanoma in situ).
    6. Patient has clinically significant cardiovascular disease (e.g., uncontrolled or any New York Heart Association Class 3 or 4 congestive heart failure, uncontrolled angina, history of myocardial infarction, unstable angina or stroke within 6 months prior to study entry, uncontrolled hypertension or clinically significant arrhythmias not controlled by medication).
    7. QT interval corrected for heart rate using Bazett's formula (QTcB) >480 msec at Screening.
    8. Patient has uncontrolled, clinically significant pulmonary disease (e.g., chronic obstructive pulmonary disease, pulmonary hypertension) that in the opinion of the investigator would put the patient at significant risk for pulmonary complications during the study.
    9. Patient has brain or leptomeningeal metastases that are symptomatic and progressive on imaging. Patients with a history of central nervous system (CNS) metastases must have received appropriate treatment. Central nervous system imaging is not required prior to study entry unless there is a history of CNS involvement or clinical suspicion of CNS involvement. Imaging of patients with a prior history of CNS metastases should be compared to prior imaging to discern disease progression.
    10. Patient has an active autoimmune disease or Grade ≥3 non-infectious 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, carbimazole) 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.
    11. Patient has a diagnosis of immunodeficiency or is 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 Cycle 1 Day 1 (C1D1).
    12. Patient has uncontrolled intercurrent illness including, but not limited to, uncontrolled infection, suspected or active SARS-CoV-2 (COVID-19) infection, disseminated intravascular coagulation, or psychiatric illness/social situations that would limit compliance with study requirements.
    13. Patient has known positive status for human immunodeficiency virus, active or chronic Hepatitis B, or Hepatitis C. Screening is not required.
    14. Patient has any medical condition which, in the opinion of the investigator, places the patient at an unacceptably high risk for toxicity.
    15. Any dysphagia, odynophagia, esophageal dysmotility or stricture, known GI malabsorption syndrome, or intractable diarrhea that may significantly alter the absorption of orally administered study drug.
    16. Patients with history of symptomatic orthostatic hypotension within 3 months prior to enrollment. Orthostatic hypotension is defined as a drop in systolic blood pressure (BP) of ≥ 20 mmHg or diastolic BP of ≥ 10 mmHg with assumption of an upright posture.
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    Study Locations

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    How to Apply

    Contact the study center to learn if this study is a good match for you.
    Phone iconCall 614-721-2630Email iconEmail Study Center

    Study’s details


    Neuroendocrine Tumors,Prostate Cancer,Small Cell Carcinoma

    Age (in years)

    18 - 200


    Phase 1/Phase 2

    Participants needed


    Est. Completion Date

    Dec 2025

    Treatment type



    BioXcel Therapeutics Inc identifier


    Study number


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