Bayer is going to have to wait for a while before Xarelto gets approved in the USA after partner Johnson & Johnson said that it is unlikely to respond to queries from the Food and Administration about the new anticoagulant before the end of the year.

The German drugmaker says it has been informed by J&J unit Ortho-McNeil that it does not expect to submit its reply to a complete response letter from the FDA issued at the end of May “until the fourth quarter of this year, at the earliest”. The companies are hoping to get Xarelto (rivaroxaban) approved for the prevention of deep vein thrombosis and pulmonary embolism in patients undergoing hip or knee replacement surgery.

The drug has already been approved in Europe and in March, the FDA’s Cardiovascular and Renal Advisory Committee voted 15 to 2 in favour of Xarelto despite concerns over bleeding and potential liver damage. While the agency said that no new clinical studies are needed as a prerequisite for approval, it has asked for “additional data from completed and ongoing studies of rivaroxaban, and from market surveillance from those countries outside the USA where the drug is currently sold to further assess the risk-benefit profile of the drug”.

The FDA also asked for additional information on the sites where the RECORD study (which forms the basis of the submission) was carried out. That study compared Xarelto with the gold-standard drug, Sanofi-Aventis’ injectable Lovenox (enoxaparin).

Kemal Malik, Bayer HealthCare's chief medical officer, said the firms were “fully convinced” of the positive risk-benefit profile of rivaroxaban, which has been approved in more than 60 countries, “and there are no new data in the clinical trials database that would change this assessment”. He added that “we want to take the time to diligently respond to all the questions raised by the FDA” and talks with the agency are planned this summer.