Hypertension as a potential biomarker of efficacy in patients with gastrointestinal stromal tumor treated with sunitinib

Background: Reliable biomarkers of sunitinib response in gastrointestinal stromal tumor (GIST) are lacking. Hypertension (HTN), an on-target class effect of vascular endothelial growth factor signaling-pathway inhibitors, has been shown to correlate with clinical outcome in advanced renal cell carcinoma treated with sunitinib. Patients and methods: This retrospective analysis examined correlations between sunitinib-associated HTN and antitumor efficacy (N = 319) and safety (N = 1565) across three advanced GIST studies. Blood pressure (BP) was measured on days 1 and 28 of each treatment cycle at a minimum. Time-to-event endpoints were estimated using Kaplan-Meier methods, and patient subgroups with and without HTN (maximum systolic BP >= 140 mmHg and/or diastolic BP >= 90 mmHg) were compared using Cox proportional hazards models. Landmark analyses evaluated associations between early HTN and efficacy endpoints. Adverse events (AEs) were compared between groups. Results: Sunitinib-associated HTN correlated with improved objective response rates, time to tumor progression, progression-free survival, and overall survival. Almost all benefits remained significant in multivariate and landmark analyses. Overall incidences of HTN-related AEs were low and similar between groups; incidences of cardiovascular AEs were somewhat higher in patients with HTN. Conclusion: Sunitinib-associated HTN appeared to correlate with improved clinical outcomes in GIST, while incidences of HTN-associated AEs were generally low and manageable.