Efficacy of cyclin-dependent kinase 4/6 inhibitors in patients with metastatic hormone positive breast cancer: a single institutional study from India

Palbociclib in HR-Positive, HER2-Negative Advanced/Metastatic Breast Cancer: A Systematic Scoping Review of Real-World Evidence from Countries Outside of Western Regions that Are Underrepresented in Clinical Trials

INTRODUCTION

Limited awareness exists regarding real-world data (RWD) for palbociclib in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced/metastatic breast cancer in populations from certain countries outside of Western regions.

METHODS

A systematic scoping review was conducted using PubMed and Embase to evaluate RWD for palbociclib from countries outside of Western regions that are underrepresented in clinical trials. Search criteria were aligned with our research question for relevant English-language publications, without restrictions on publication date, followed by Phase 1 (title and abstract) and Phase 2 (full-text) screening of retrieved citations as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data analyses of eligible studies were done separately for abstracts and full-text publications to enhance the precision and reliability of the results.

RESULTS

Database search yielded 1485 non-duplicate records, 46 qualified for inclusion, of which 47.8% were published as full text. The analysis of outcomes, based exclusively on full-text publications that collectively included 2048 patients treated with palbociclib, revealed the median progression-free survival (PFS) of 20.2-36.7 months, overall survival (OS) of 39.9 months (reported in one publication) and objective response rate (ORR) of 45.3-80.0% with first-line treatment. In ≥ second line, the median PFS, OS and ORR ranged from 7.0 to 24.2 months, 11 to 19.6 months, and 13.9% to 47.9%, respectively. The safety profile of palbociclib was similar to that reported in pivotal clinical studies, and no new safety concerns were identified.

CONCLUSIONS

A comprehensive volume of evidence demonstrates that palbociclib's effectiveness and safety profile in real-world settings align with those observed in clinical trials, offering valuable insights for clinical decision-making in countries outside of Western regions underrepresented in clinical trials.

Cost-Effectiveness of Adjuvant Abemaciclib and Ribociclib in High-Risk Hormone Receptor-Positive Early Breast Cancer: An Indian Perspective

PURPOSE

Incorporating adjuvant cyclin-dependent kinase (CDK) 4/6 inhibitors abemaciclib and ribociclib along with endocrine therapy has been shown to improve invasive disease-free survival (iDFS) for hormone receptor-positive (HR+) human epidermal receptor 2-negative (HER2-) early breast cancer (EBC). This study assesses the cost-effectiveness of this strategy, along with adjuvant aromatase inhibitors from an Indian perspective.

METHODS

A Markov chain model evaluated the cost-effectiveness of abemaciclib and ribociclib with letrozole compared with letrozole alone for HR+/HER2- EBC from a payer perspective in India. Key measures included lifetime quality-adjusted life-years (QALY), life-years (LY), and total costs. This study explores two scenarios for effectiveness: a best-case (BC) scenario, where the benefit of CDK4/6 inhibitors in improving iDFS lasts a lifetime, and a worst-case (WC) scenario, where benefits disappear after 5 years. Probabilistic sensitivity analyses (PSA) were used to account for simulation uncertainty.

RESULTS

In the BC scenario, abemaciclib added 2.17 QALY and 4.96 LY, incurring ₹2,317,957.7 ($27,756.65 in US dollars [USD]) in additional costs. However, the incremental cost-effectiveness ratio (ICER) for abemaciclib exceeded India's willingness-to-pay threshold in the BC and WC scenarios. In the BC scenario, ribociclib added 0.98 QALY and 2.58 LY with added costs of ₹1,711,504.32 ($20,494.6 USD). The ICER for ribociclib also surpassed India's threshold in both scenarios. PSA showed that neither drug was cost-effective at the current market prices in either BC/WC scenario. The cost of abemaciclib and ribociclib needs to be reduced by at least 78.61% and 87.19%, respectively, to be cost-effective in the BC scenario.

CONCLUSION

The combination of adjuvant abemaciclib or ribociclib with letrozole is not cost-effective for HR+/HER2- EBC in India in either the BC or WC scenario.

An Overview of the Safety Profile and Clinical Impact of CDK4/6 Inhibitors in Breast Cancer-A Systematic Review of Randomized Phase II and III Clinical Trials

Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is) have transformed the treatment of hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer over the last decade. These inhibitors are currently established as first- and second-line systemic treatment choices for both endocrine-sensitive and -resistant breast cancer populations alongside endocrine therapy (ET) or monotherapy. Data on targeted therapy continue to mature, and the number of publications has been constantly rising. Although these drugs have been demonstrated to prolong overall survival (as well as progression-free survival (PFS) in breast cancer patients), changing the paradigm of all current knowledge, they also cause important adverse events (AEs). This review provides the latest summary and update on the safety profile of the three CDK4/6 inhibitors, as it appears from all major phase II and III randomized clinical trials regarding palbociclib, ribociclib, and abemaciclib, including the most relevant 15 clinical trials.