Post-CDK 4/6 Inhibitor Therapy: Current Agents and Novel Targets

Area of Science:

• Oncology
• Pharmacology
• Clinical Medicine

Background:

• Advanced and metastatic hormone receptor-positive (HR+), HER2-negative (HER-) breast cancer (mBC) is primarily treated with endocrine therapy plus a CDK4/6 inhibitor (CDK4/6i) as front-line therapy.
• CDK4/6 inhibitors have significantly improved progression-free survival and overall survival in this patient population.
• Personalized sequencing of post-front-line therapies is crucial, considering individual patient health and specific tumor biology.

Purpose of the Study:

• To review approved second-line therapies for mBC following CDK4/6i treatment.
• To analyze available efficacy data for treatments used after progression on CDK4/6i.
• To discuss novel therapies under investigation for HR+, HER2- mBC, including those targeting estrogen receptor pathways and overcoming CDK4/6i resistance.

Main Methods:

• Literature review of approved therapies and clinical trial data.
• Analysis of efficacy and adverse event data for post-progression treatments.
• Synthesis of information on emerging therapeutic strategies and ongoing clinical investigations.

Main Results:

• CDK4/6 inhibitors represent a cornerstone of front-line treatment for HR+, HER2- mBC, enhancing survival outcomes.
• Several therapeutic options are available for subsequent lines of therapy, with efficacy varying based on prior treatment and patient characteristics.
• Ongoing research focuses on novel endocrine-based strategies and overcoming resistance mechanisms to CDK4/6 inhibitors.

Conclusions:

• The management of HR+, HER2- mBC has been revolutionized by CDK4/6 inhibitors, necessitating a strategic approach to subsequent treatment lines.
• Personalized medicine, integrating patient factors and tumor biology, is key to optimizing outcomes in advanced or metastatic breast cancer.
• Continued investigation into novel agents and combination therapies is essential to further improve survival and quality of life for patients with refractory or resistant disease.