Abemaciclib (LY2835219) in Men With Heavily Treated Metastatic Castration-Resistant Prostate Cancer

Inclusion Criteria

• Participant must have metastatic prostate cancer for which castration (medical or surgical) is no longer effective (castration-resistant).
• Participant must have disease spread to soft tissue that is measurable.
• Participant must have documented evidence of progressive disease by PSA test or imaging.
• Participant must have previously received at least one of the following treatment: abiraterone acetate, apalutamide, darolutamide or enzalutamide.
• Participant must have previously received chemotherapy with docetaxel and cabazitaxel.
• Participant must be willing and amenable to undergo a biopsy of tumor tissue (or able to provide adequate archived tumor tissue sample) and to provide blood for research.
• Participant must have good physical functioning ability and adequate organ function.

Exclusion Criteria

• Participant must not have received more than 3 therapy regimens for metastatic castration-resistant prostate cancer (NOTE: GnRHa, first-generation antiandrogens (flutamide, nilutamide, or bicalutamide), diethylstilbestrol (DES) (or other estrogens), corticosteroids, ketoconazole, and bone loss-prevention will not count as systemic therapy regimens.
• Participants must not have previously received abemaciclib or any cyclin-dependent kinase (CDK)4 and/or CDK6 inhibitors.
• Participants must not have serious and/or uncontrolled preexisting medical condition(s) including but not limited to severe renal impairment, severe hepatic impairment, interstitial lung disease (ILD)/pneumonitis, severe dyspnea at rest or requiring oxygen therapy or other serious preexisting medical condition(s) that, in the judgment of the investigator, would preclude participation in this study.
• Participants must not have, or suspected to have, brain metastasis.
• Participants must not have untreated spinal cord compression, evidence of spinal metastases with risk of spinal compression or structurally unstable bone lesions suggesting impending fracture.