Evaluation of alpelisib-induced hyperglycemia prophylaxis and associated risk factors in PIK3CA-mutated hormone-receptor positive, human epidermal growth factor-2 negative advanced breast cancer.

PURPOSE: SOLAR-1 investigated alpelisib-fulvestrant (ALP + FLV) in patients with HR + /HER2-, PIK3CA-mutated advanced breast cancer and demonstrated a clinically significant increase in all-grade and grade (G) 3-4 hyperglycemia (HG) compared to placebo-fulvestrant. Given high rates of HG, a preventative protocol and identification of associated risk factors was implemented. METHODS: This single-center, retrospective study included patients receiving ALP + FLV. One week before ALP initiation, patients started an insulin-sensitizer. Patients had fasting plasma glucose (FPG) levels drawn day 8, 15, 28, then monthly. Primary outcome was incidence of G2-4 HG by day 28. Risk factors assessed included age, BMI, FPG, and HbA1c. Number of risk factors were compared between patients with and without HG. RESULTS: Sixteen women were included with median age of 59 years. The cohort was 69% White, 25% Black, 75% with BMI ≥ 25 kg/m2, and 50% with history of diabetes. By day 28, 9 patients (56%) had G2-4 HG, with only 3 (19%) G3 and zero G4. Patients with G2-4 HG had a median of 2 risk factors compared to only 1 if no HG (p = 0.03). 5 patients (31%) required a temporary hold of ALP and 3 (19%) required dose reduction due to HG. 13 patients permanently discontinued ALP-9 due to disease progression and 4 from an adverse event (only 1 HG). CONCLUSION: Implementation of a HG prophylaxis protocol with ALP in a single-center study demonstrated fewer G3-4 HG events compared to that seen in SOLAR-1 (19% vs 36.6%). An increase in HG-associated risk factors correlated with a higher incidence of G2-4 HG.

Cardiovascular Toxicity of Novel HER2-Targeted Therapies in the Treatment of Breast Cancer.

PURPOSE OF REVIEW: HER2-targeted therapies have led to improved clinical outcomes in early and advanced breast cancer (BC). We review the long-term cardiotoxicity of HER2-targeted therapy in early and advanced BC, our current knowledge of cardiotoxicity of novel HER2-targeted therapies, and propose a cardiac monitoring (CM) strategy for this population. RECENT FINDINGS: Long-term data from studies with HER2-targeted therapy in the adjuvant setting have failed to demonstrate an increase in cardiotoxicity over time, and rates of cardiotoxicity seen with novel HER2 agents remain low. Despite over a decade of experience with HER2-targeted therapy, CM in clinical practice is inconsistent in patients with early BC and almost non-existent in advanced BC. Long-term follow-up of clinical trials with HER2-targeted agents in early and advanced BC has failed to demonstrate increased rates of cardiotoxicity over time, attesting to the long-term safety of this class of drugs for the majority of patients, although the long-term cardiac safety of newer HER2 agents in the non-clinical trial setting is largely unknown. We propose CM incorporating clinical history, cardiac imaging, and biomarkers.