The Role of CDK4/6 Inhibition in Breast Cancer. (15th April 2015)

• Record Type: Journal Article
• Authors: Murphy, Conleth G.; Dickler, Maura N.
• Is Part Of: Oncologist. Volume 20:Number 5(2015)
• Page Start: 483
• Page End: 490
• Publication Date: 2015-04-15
• Subjects: Breast neoplasms -- Inhibitors of cyclin‐dependent kinase 4 proteins -- Palbociclib -- LEE011 -- Abemaciclib -- Flavopiridol; Oncology -- Periodicals; Tumors -- Periodicals; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Oncology; Tumors; Neoplasms; Electronic journals; Periodicals; Periodicals; 616.994
• DOI: 10.1634/theoncologist.2014-0443
• Languages: English
• ISSNs: 1083-7159

Abstract

Abstract : Imbalance of the cyclin D and cyclin‐dependent kinase (CDK) pathway in cancer cells may result in diversion away from a pathway to senescence and toward a more proliferative phenotype. Cancer cells may increase cyclin D‐dependent activity through a variety of mechanisms. Therapeutic inhibition of CDKs in tumors to negate their evasion of growth suppressors has been identified as a key anticancer strategy. In this review, we outline the development of CDK inhibitory therapy in breast cancer, including the initial experience with the pan‐CDK inhibitor flavopiridol and the next generation of oral highly selective CDK4 and CDK6 inhibitors PD0332991 (palbociclib), LEE011 (ribociclib), and LY2835219 (abemaciclib). Data from phase I and II studies in estrogen receptor‐positive (ER+) breast cancer demonstrate promising efficacy with manageable toxic effects, chiefly neutropenia. We discuss these studies and the phase III studies that are accruing or nearing completion. We describe the application of such therapy to other breast cancer settings, including HER2‐positive breast cancer and the adjuvant treatment of early breast cancer. We also discuss potential concerns surrounding the combination of CDK inhibitors with chemotherapy and their effects on repair of double‐strand DNA breaks in cancer cells. Oral highly selective CDK inhibitors show great promise in improving the outcomes of patients with ER+ breast cancer, although caution must apply to their combination with other agents and in the early breast cancer setting. Abstract : This paper reviews the role of CDK4/6 in tumorigenesis and summarizes the clinical trial experience with inhibitors of these kinases in breast cancer, including key efficacy and toxicity data. The results with oral CDK4/6 inhibitors to date have offered promising glimpses of significant activity in hormone‐sensitive breast cancer. This activity, combined with a favorable toxicity profile, makes this family of novel therapies very exciting.