Kisqali (ribociclib)

The majority of patients (72%) were treated in the first-line setting; 11 received ribociclib, 15 received palbociclib, and 3 received abemaciclib. Whether this translates into deferring disease progression requires randomized studies with larger treatment groups. To our knowledge, this study represents the first analysis evaluating 18F-FDG-PET/CT-guided SBRT in combination with CDK4/6 inhibitor-based therapy in patients with metastatic breast cancer.

P1, N=48, Recruiting, Novartis Pharmaceuticals | Active, not recruiting --> Recruiting

Palbociclib, ribociclib, and abemaciclib, which are FDA-approved CDK4/6 inhibitors, constitute the standard first-line treatment for advanced hormone receptor-positive (HR+) breast cancers. Collectively, this study deepens the understanding of shared and drug-specific molecular characteristics and mechanisms of CDK4/6 inhibitors at multi-omic levels. Moreover, it provides an experimental basis and potential directions for customizing combination therapies based on pathway vulnerabilities, as well as exploration of novel therapeutic modes and drugs.

P4, N=90, Not yet recruiting, Institute of Oncology Ljubljana

P3, N=1978, Recruiting, National Cancer Institute (NCI) | Not yet recruiting --> Recruiting | Initiation date: Jul 2026 --> Feb 2027

P1, N=48, Active, not recruiting, Novartis Pharmaceuticals | Recruiting --> Active, not recruiting

P2, N=160, Not yet recruiting, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University

This article mainly reviews the mechanisms of action, clinical efficacy, and current application status of CDK4/6 inhibitors, including Palbociclib, Ribociclib, Abemaciclib, and the emerging Dalpiciclib. Strategies such as combining phosphoinositide 3-kinase (PI3K) inhibitors, immunotherapy, or new estrogen receptor (ER)-degrading agents are being actively explored for drug-resistant patients. The personalized precision therapy may become the core direction for optimizing the application of CDK4/6 inhibitors in the future, which will improve patients' quality of life.

P2, N=150, Recruiting, MedSIR | Not yet recruiting --> Recruiting | Initiation date: Dec 2025 --> Mar 2026

P2, N=216, Completed, Melanoma Institute Australia | Trial completion date: Dec 2025 --> Mar 2026

CDK4/6 inhibitors represent one of the most important treatment options for HR+/HER2- metastatic breast cancer. Regardless of their clinical efficacy, cutaneous adverse events remain a common source of patient discomfort. Therefore, careful clinical attention and appropriate supportive care are essential to improve patients' quality of life.

This retrospective study included HR-positive/HER2-negative metastatic breast cancer patients treated with ribociclib or palbociclib at Necmettin Erbakan University between May 2020 and April 2025. Lower baseline UAR was associated with more favorable survival outcomes in HR-positive/HER2-negative metastatic breast cancer patients treated with CDK4/6 inhibitors. As an inexpensive and easily accessible biomarker derived from routine laboratory parameters, UAR may provide additional prognostic information for clinical risk stratification.