Real-World Evaluation of Disease Progression After CDK 4/6 Inhibitor Therapy in Patients With Hormone Receptor-Positive Metastatic Breast Cancer.

BACKGROUND: Cyclin-dependent kinase 4/6 inhibitors (CDKi) have changed the landscape for treatment of patients with hormone receptor positive, human epidermal growth factor receptor 2-negative (HR+/HER-) metastatic breast cancer (MBC). However, next-line treatment strategies after CDKi progression are not yet optimized. We report here the impact of clinical and genomic factors on post-CDKi outcomes in a single institution cohort of HR+/HER2- patients with MBC. METHODS: We retrospectively reviewed the medical records of patients with HR+/HER2- MBC that received a CDKi between April 1, 2014 and December 1, 2019 at our institution. Data were summarized using descriptive statistics, the Kaplan-Meier method, and regression models. RESULTS: We identified 140 patients with HR+/HER2- MBC that received a CDKi. Eighty percent of patients discontinued treatment due to disease progression, with a median progression-free survival (PFS) of 6.0 months (95% CI, 5.0-7.1), whereas those that discontinued CDKi for other reasons had a PFS of 11.3 months (95% CI, 4.6-19.4) (hazard ratio (HR) 2.53, 95% CI, 1.50-4.26 [P = .001]). The 6-month cumulative incidence of post-CDKi progression or death was 51% for the 112 patients who progressed on CDKi. Patients harboring PTEN mutations pre-CDKi treatment had poorer clinical outcomes compared to those with wild-type PTEN. CONCLUSION: This study highlights post-CDKi outcomes and the need for further molecular characterization and novel therapies to improve treatments for patients with HR+/HER2- MBC.

CDK 4/6 inhibitors are associated with a high incidence of thrombotic events in women with breast cancer in real-world practice.

PURPOSE: Cyclin-dependent kinase (CDK) 4/6 inhibitors are integral treatment for advanced hormone receptor positive breast cancer; however, venous thromboembolic events (VTE) occurred in 1%-5% of clinical trial patients. Thrombosis rates in the real-world setting remain unclear. We aimed to define the rate of thromboembolic events, risk factors for thrombosis on CDK 4/6 inhibitors and evaluate the Khorana VTE risk score as a predictive tool for VTE in patients on CDK 4/6 therapy. METHODS: Multicenter retrospective analysis of adult breast cancer patients prescribed palbociclib, ribociclib, or abemaciclib. The primary endpoint was thrombosis during treatment or within 30 days of CDK inhibitor discontinuation. Cox regression was used to model time-to-thrombosis, starting from a patient's initiation of CDK 4/6 therapy. The extended Kaplan-Meier method and Cox modeling were used to assess the effect of time-varying thrombosis status on overall survival. RESULTS: Two hundred and sixty-six patients were included (89% on palbociclib, 14% on abemaciclib, 7% on ribociclib). Twenty-nine thrombotic events occurred in 26 (9.8%) women. Of these events, 72% were venous and 34% were arterial. The 1-year incidence of thrombosis was 10.4% overall, 10.9% on palbociclib, 8.3% on ribociclib, and 4.8% on abemaciclib. Hemoglobin less than 10 g/dL was a statistically significant predictor of thrombosis (HR 3.53, P: .014). Khorana score ranged from 0-3, with the majority between 0 and 1 and was not predictive of VTE. Thrombosis was associated with reduced overall survival (HR 1.28, P: .128, median 7.3 months) compared to not having a CDK-associated clot (median 35.7 months). DISCUSSION: VTE in our analysis is higher than reported in clinical trials and arterial thrombosis comprised over one-third of events. The highest incidence was with palbociclib, followed by ribociclib. Khorana score did not predict VTE risk. Larger, real-world studies are needed. The role for prophylactic anticoagulation is yet to be defined in this patient population.

The many roles of tranexamic acid: An overview of the clinical indications for TXA in medical and surgical patients.

Clinically significant bleeding can occur as a consequence of surgery, trauma, obstetric complications, anticoagulation, and a wide variety of disorders of hemostasis. As the causes of bleeding are diverse and not always immediately apparent, the availability of a safe, effective, and non-specific hemostatic agent is vital in a wide range of clinical settings, with antifibrinolytic agents often utilized for this purpose. Tranexamic acid (TXA) is one of the most commonly used and widely researched antifibrinolytic agents; its role in postpartum hemorrhage, menorrhagia, trauma-associated hemorrhage, and surgical bleeding has been well defined. However, the utility of TXA goes beyond these common indications, with accumulating data suggesting its ability to reduce bleeding and improve clinical outcomes in the face of many different hemostatic challenges, without a clear increase in thrombotic risk. Herein, we review the literature and provide practical suggestions for clinical use of TXA across a broad spectrum of bleeding disorders.