Abemaciclib in Combination With Androgen Deprivation Therapy for Locally Advanced Prostate Cancer — RAD 1805  

Prostate Cancer Clinical Trial

Official title: Phase II Clinical Trial of Abemaciclib in Combination With Androgen Deprivation Therapy for Locally Advanced Prostate Cancer

Status Active, not recruiting

Clinical Trial Summary

This Phase II study is designed to study the clinical and radiologic response, as well as, safety and tolerability of abemaciclib in combination with androgen deprivation therapy (ADT) in patients with localized high-risk or locally advanced prostate cancer who are eligible for definitive radiation therapy (RT) and androgen deprivation therapy (ADT).

Clinical Trial Description

A similar hormone-driven cancer akin to breast cancers is prostate cancer. These tumors are driven by androgen receptor signaling, and CDK4/6 has also been found to be a bona fide target pre-clinically for advanced prostate cancer cell models. Moreover, CDK4/6 inhibition can act as a radiation sensitizer through its effects on the DNA damage response and interactions with cell cycle pathway proteins. For example, it has been found that expression of DNA repair proteins can be regulated by E2F, a transcription factor necessary for the G1 to S phase transition. Also, cyclin D1 has been found to exert a direct role in DNA repair. Lastly, CDK4/6 inhibition has been found to modulate the DNA damage response. These data support the use of CDK4/6 inhibitors as a modulator of DNA damage to enhance sensitivity to radiation.

Given the role of CDK4/6 in tumor resistance to endocrine therapy, in activation of the DNA damage response, and in promoting radiation resistance, we hypothesize that the targeting of CDK4/6 with abemaciclib will enhance the cytotoxicity in combination with blockade of the androgen receptor pathway. Therefore, we propose a pilot phase II investigator initiated trial in patients with high-risk prostate cancer testing the tolerability and toxicity of abemaciclib in combination with ADT.

Patients will receive ADT for 2 years and will start 3 months before radiation therapy. Abemaciclib will start with initiation of ADT and pause 2 weeks prior to start of radiation therapy. Abemaciclib will resume with the first ADT administration post-radiation, which is about 1 month post radiation therapy. Abemaciclib and ADT will continue for a total ADT period of 24 months. Patients will receive study treatment until development of toxicity or disease progression on treatment or any reasons of withdrawal or a maximum of 24 months of therapy with ADT. Patients are seen every 4 weeks with laboratory evaluation. For toxicity or adverse events, patients will undergo labs, physical examination and grades of toxicities will be determined using NCI CTCAE version 4.03. ;

Related Conditions & MeSH terms

• Prostate Cancer
• Prostatic Neoplasms

• NCT number: NCT04298983
• Study type: Interventional
• Source: University of Alabama at Birmingham
• Status: Active, not recruiting
• Phase: Phase 2
• Start date: February 25, 2021
• Completion date: April 2026