Bayer's partner Johnson & Johnson has swiftly responded to a complete response letter issued by US regulators to expand use of the bloodthinner Xarelto to prevent heart attacks and strokes in patients with acute coronary syndrome.

In June, the US Food and Drug Administration declined to approve Xarelto (rivaroxaban) to reduce the risk of secondary cardiovascular events in patients with ACS and requested further information. The specifics of the agency's request were not revealed but one of its advisory committees had voted against approval for this indication, citing concerns about the increased risk of major and fatal bleeding.

J&J's Janssen unit also has resubmitted the supplemental New Drug Application for Xarelto to reduce the risk of stent thrombosis in patients with ACS, which the company withdrew on July 9, based on its connection to the aforementioned sNDA. Data from the ATLAS ACS 2 TIMI 51 trial support both the filings.

Paul Burton, vice president at Janssen R&D, said "we are confident in the results of the ATLAS ACS 2 TIMI 51 trial and have relied on the data from that study to develop our comprehensive responses to questions raised by the FDA". Xarelto is approved for three uses in the USA - to reduce the risk of blood clots in people who have just had knee and hip replacement surgery, and to prevent haemorrhagic and thrombotic strokes as well as other blood clots in people with atrial fibrillation not caused by a heart valve problem.