Zhang, Xuan

ABSTRACT Introduction Although covalent Bruton's tyrosine kinase inhibitors (cBTKis) have transformed treatment of chronic lymphocytic leukemia and small lymphocytic leukemia (CLL/SLL), cBTKi‐related cardiotoxicity is a known side effect. This real‐world study evaluated incident cardiovascular adverse events (CVAE), healthcare resource utilization (HCRU), and costs among patients with CLL/SLL receiving cBTKis. Methods Adult patients with CLL/SLL who initiated ibrutinib or acalabrutinib treatment (index date) between 2020 and 2023 were identified using US claims data and followed up to 36 months post‐index. Incident CVAEs (not present pre‐index) were assessed during cBTKi treatment and patients were stratified by CVAE status. HCRU and costs were evaluated per 1000 patient‐months (PPPM). Results Overall, 2069 patients were identified (mean age of 73.7 ± 9.1 years, 40.4% female) with a mean treatment‐specific observation period of 11.4 ± 9.5 months. At least one incident CVAE was observed in 442 (21.4%) patients. The incidence rate was 21.6 PPPM for hypertension, 8.9 PPPM for atrial fibrillation, 8.6 PPPM for ventricular arrhythmias, and 8.3 PPPM for atrial flutter. Patients with incident CVAEs had significantly more total medical service days PPPM (4334 vs. 3138, p < 0.001), primarily driven by increased inpatient (690 vs. 230), outpatient (2798 vs. 2425), other visit (662 vs. 375), and ER days (184 vs. 109) than those without CVAEs. Total healthcare costs (PPPM) were substantially higher for patients with incident CVAEs ($20,250,560 vs. $17,413,460, p < 0.001) mainly due to higher inpatient ($3,417,948 vs. $915,839, p < 0.001), outpatient ($2,415,060 vs. $1,769,628, p < 0.01), and ER costs ($186,820 vs. $87,585, p < 0.001). Conclusions The observed class‐effect of high CVAEs with cBTKis underscores the unmet need for safer, more selective agents for CLL/SLL treatment. The HCRU and economic burden remain high for CLL/SLL, especially among patients experiencing CVAEs during cBTKi treatment. These findings emphasize the importance of optimizing clinical management to reduce CVAE risk and downstream impacts on HCRU and costs.

Abstract FoxM1, a member of the Forkhead transfection factors, has been found to be overexpressed in many human cancers including ovarian cancer. Although FoxM1 is known to be downregulated by p53, the molecular mechanisms are not well characterized. In this study, we used the MDM2 inhibitor Nutlin-3 as a tool to modulate p53 expression and investigated the mechanism by which p53 regulates FoxM1 expression in ovarian cancer cells. We observed that Nutlin-3 upregulated p53 protein and downregulated FoxM1 mRNA and protein levels in ovarian cancer cell lines with wild type TP53, but not in cell lines with mutant TP53. This effect was at least partially blocked by cycloheximide or actinomycin D, indicating a transcription- and translation-dependent mechanism. Pulse-chase studies revealed that downregulation of FoxM1 by Nutlin-3 is due to enhanced FoxM1 mRNA decay. Knockdown of p53 using shRNAs abrogated the suppression of FoxM1 expression by Nutlin-3, indicating a p53-dependent mechanism. Furthermore, silencing of FoxM1 by shRNAs in ovarian cancer cells with or without wild-type TP53 led to a significant decrease in cell proliferation. The FoxM1 inhibitor, thiostrepton, induces cytotoxicity in ovarian cancer cell lines and enhances sensitivity to cisplatin in these cells. Thiostrepton downregulates FoxM1 expression in several ovarian cancer cell lines and enhances sensitivity to carboplatin in vivo. Finally, FoxM1 expression is elevated in nearly all (47/48) ovarian tumors. In summary, the present study provides novel evidence that p53 downregulates FoxM1 in ovarian cancer cells at least in part by destabilizing FoxM1 mRNA and that FoxM1 may be targeted for therapeutic benefits in ovarian cancer. Citation Format: Xuan Zhang, Lihua Cheng, Kay Minn, Magdalena Waggoner, Nikhil K. Parelkar, Iman Jokar, George A. Vielhauer, Rashna Madan, Andrew K. Godwin, Viji Shridhar,, Jeremy Chien. Targeting p53-FoxM1 axis in ovarian cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1409.