Bayer, along with its development partner Janssen Research & Development, has halted the phase III Navigate ESUS study of rivaroxaban (Xarelto), as it demonstrated comparable efficacy between treatment arms.

The study is assessing the efficacy and safety of anticoagulant medicine for the secondary prevention of stroke and systemic embolism in patients with a recent embolic stroke of undetermined source (ESUS).

The independent data monitoring committee (IDMC) has recommended to stop the trial as it showed comparable efficacy between the rivaroxaban and aspirin arms and little chance of demonstrating overall benefit after the completion of the study.

Navigate ESUS phase III trial has recruited 7,214 patients at 459 sites in across 31 countries. They have been randomized to secure either rivaroxaban 15mg once daily or aspirin 10 mg once daily alone.

Primary efficacy endpoint was a composite of stroke and systemic embolism. The primary safety endpoint was major bleeding as per criteria of the International Society on Thrombosis and Haemostasis (ISTH), the primary safety endpoint was major bleeding

Rivaroxaban is the mostly indicated non-vitamin K antagonist oral anticoagulant (NOAC), which  is marketed under the brand name Xarelto.

Xarelto secured approval for seven indications, including for the treatment of pulmonary embolism (PE) in adults, deep vein thrombosis (DVT) in adults and prevention of recurrent PE and DVT in adults,

It can also be used to prevent venous thromboembolism (VTE) in adult patients undergoing elective hip replacement surgery, in addition to VTE in adult patients undergoing elective knee replacement surgery

Discovered by Bayer, Rivaroxaban is being jointly developed by both firms. Bayer markets Xarelto outside the US, while Janssen Pharmaceuticals in the US.

Bayer Pharmaceutical Division executive committee member Dr Joerg Moeller said: “Patients with ESUS currently have limited treatment options and the role of anticoagulants in this area remains uncertain.

“We will now analyse the data from Navigate ESUS to better understand this outcome and its implications.”