The effects of the spleen tyrosine kinase inhibitor fostamatinib on ambulatory blood pressure in patients with active rheumatoid arthritis: results of the OSKIRA-ABPM (ambulatory blood pressure monitoring) randomized trial

Clinical trials of fostamatinib in patients with rheumatoid arthritis showed blood pressure (BP) elevation using clinic measurements. The OSKIRA-ambulatory BP monitoring trial assessed the effect of fostamatinib on 24–hour ambulatory systolic BP (SBP) in patients with active rheumatoid arthritis. One hundred thirty–five patients were randomized to fostamatinib 100 mg twice daily (bid; n = 68) or placebo bid (n = 67) for 28 days. Ambulatory, clinic, and home BPs were measured at baseline and after 28 days of therapy. Primary end point was change from baseline in 24–hour mean SBP. Fostamatinib increased 24–hour mean SBP by 2.9 mm Hg (P = .023) and diastolic BP (DBP) by 3.5 mm Hg (P < .001) versus placebo. Clinic/home-measured BPs were similar to those observed with ambulatory BP monitoring. After treatment discontinuation (1 week), clinic BP values returned to baseline levels. Fostamatinib induced elevations in 24–hour mean ambulatory SBP and DBP. BP elevations resolved with fostamatinib discontinuation.