BAY 43-9006 (sorafenib) is an inhibitor of Raf kinase, the vascular endothelial growth factor (VEGF) receptor-2, and angiogenesis in tumor xenografts. The current study investigated the incidence, severity, and mechanism of blood pressure (BP) elevation in patients treated with BAY 43-9006.

Twenty patients received BAY 43-9006 400 mg orally twice daily. BP and heart rate were measured at baseline and then every 3 weeks for 18 weeks. VEGF, catecholamines, endothelin I, urotensin II, renin, and aldosterone were measured at baseline and after 3 weeks of therapy. We assessed vascular stiffness at baseline, after 3 to 6 weeks of therapy, and again after 9 to 10 months of therapy.

Fifteen (75%) of 20 patients experienced an increase of ≥ 10 mmHg in systolic BP (SBP), and 12 (60%) of 20 patients experienced an increase of ≥ 20 mmHg in SBP compared with their baseline value, with a mean change of 20.6 mmHg (P < .0001) after 3 weeks of therapy. There were no statistically significant changes in humoral factors, although there was a statistically significant inverse relationship between decreases in catecholamines and increases in SBP, suggesting a secondary response to BP elevation. Measures of vascular stiffness increased significantly during the period of observation.

Treatment with BAY 43-9006 is associated with a significant and sustained increase in BP. The lack of significant change in circulating factors suggests that these humoral factors had little role in the increase in BP.