A major postmarketing study in Japan on Bayer's Xarelto (rivaroxaban) marks a first in postmarketing trial patient reach that stems from a recent call by the Pharmaceuticals and Medical Devices Agency (PMDA). The initiative is designed to help compare narrower clinical trial numbers with actual use cases.
In Japan, as in other Asian nations such as China, drug approvals rest on gathering ethnic-specific clinical data to potentially identify variations among broader patient pools. This is especially the case with initial data from trials primarily conducted in the U.S. and Europe. Xarelto was approved in China in May 2015 for stroke prevention in adult patients with nonvalvular atrial fibrillation and one or more risk factors.
In addition, the PMDA has also required postmarketing studies, usually with patient numbers in the hundreds or less.
But the work on once-daily oral anticoagulant rivaroxaban in Japan jibed with an official policy push for larger patient pools in postmarketing and set a milestone with 11,000 patients over two years from April 2012 to June 2014, according to members of a team led by Takanori Ikeda, division director for Cardiovascular Medicine at Toho University Omori Hospital.
The postmarketing effort also sets a standard for postapproval drug trial in Japan related to a disease area, stroke, that afflicts a rapidly aging population in the country as it showed low rates of both stroke and major bleeding in patients with non-valvular AF newly initiated on rivaroxaban in routine clinical practice, according to a press release from Bayer.
"These results were generally consistent with the Phase III J-ROCKET AF randomized clinical trial."
Takeda, in a poster presentation at the European Society of Cardiology in Rome, suggested the real-world data also aided clarity on dosing that suggested a higher dose of 15 milligrams was more appropriate than a standard followed by many doctors of 10 milligrams made based in part on body weight among Japanese patients which tended to be lower than Caucasian patients in the clinical trial.
"Japan-specific doses of rivaroxaban could be useful," Takeda said in the Aug. 29 presentation slide notes provided to FiercePharmaAsia.
In the second-quarter earnings call, Bayer noted that sales of Xarelto and age-related macular degeneration treatment Eylea (aflibercept) in Asia were important drivers in the region. Executives said the company has 70% of the market in Japan with Eylea, and 31% for Xarelto in the country against therapies that include warfarin (Coumadin) among others.
- here's the release