Bristol-Myers Squibb has entered into a pact with two Japanese companies to develop an early-stage drug for the treatment of irregular heartbeat.

The companies in question are Nissan Chemical Industries and Teijin Pharma and the deal gives B-MS exclusive worldwide rights (excluding Japan) to develop and sell NTC-801. The drug, which is in Phase I trials, is a selective inhibitor of the acetylcholine-activated potassium ion channel which is being studied for the maintenance of normal sinus rhythm in patients with atrial fibrillation, or flutter.

Cashwise, B-MS is making an upfront payment of $40 million and Nissan Chemical and Teijin could receive development and sales milestones of up to $345 million, plus royalties. The New York-based firm has also secured the rights to certain back-up compounds.

Francis Cuss, B-MS’ senior vice president for discovery and exploratory clinical research, said the deal is important as "there is significant unmet medical need for a more effective and safer therapy for atrial fibrillation". He added that NTC-801, to which Nissan Chemical previously granted Teijin Japanese rights, “provides us with the opportunity to leverage our company’s deep expertise in helping patients prevail over cardiovascular disease”.

B-MS currently has a drug in Phase III, apixaban, which is being studied for the prevention of thrombotic events, such as stroke in patients with atrial fibrillation. The compound is being developed with Pfizer.