Eisai/ Arena agreement for lorcaserin

Eisai Inc, the US pharmaceutical operation of Japan-based Eisai Co, has entered into an agreement with Arena Pharmaceuticals for the rights to commercialise lorcaserin, a drug candidate in development for the treatment of obesity.

Eisai will initially pay Arena an upfront payment of $50m, with additional milestone payments of up to $90m dependent upon regulatory approval as well as the delivery of product supply for launch.

Arena will also receive 31.5 per cent of Eisai's annual net sales of lorcaserin, with this increasing on a tiered basis to as high as 36.5 per cent for further sales of the product once net sales have exceeded $750m.

Jack Lief, Arena's president and CEO described the agreement as a "major milestone" in the company's plans for lorcaserin – a drug with the potential to be the first in a new class of selective serotonin 2C receptor agonists.

Serotonin 2C receptor is expressed in the hypothalamus – a part of the brain involved in appetite and metabolism – with stimulation of the receptor associated with an individual's feeding habits.

If approved by the US Food and Drug Administration (FDA), Eisai aims to commercialise the product in the US for use in the treatment of obesity, including weight loss, for patients who are obese with at least one weight-related co-morbid condition.

Eisai will handle all marketing and distribution activity in the US, with Arena manufacturing the product in Switzerland.

"Through this agreement, we believe Eisai has an opportunity to bring a new option to market to address the significant and growing need for medical obesity treatments,” said Lonnel Coats, president and CEO, Eisai Inc.

"Additionally, by building on our expertise and success in the primary care and speciality areas, with strong synergy in our gastrointestinal franchise, this arrangement will enable Eisai to establish a strong presence in the United States for the medical management of obesity."