Eisai in up to $1.37 billion deal for Arena Pharma's' lorcaserin for obesity in USA

USA-based Arena Pharmaceuticals has reached an agreement with Japanese drug major Eisai worth potentially $1.37 billion to fund commercialization of an obesity drug that could become Arena's first marketed product.

The accord means that Eisai will market Arena's lorcaserin for obesity and weight management in the USA following Food and Drug Administration approval under the terms of a marketing and supply agreement between Eisai and the US firm's wholly-owned Arena Pharmaceuticals GmbH (which will produce the product in Switzerland for the US market). Lorcaserin, which Arena discovered and has developed for weight management, is intended for obese patients as well as overweight patients who have at least one weight-related co-morbid condition.

Under the terms of the deal, Arena will receive an upfront $50 million from Eisai and, upon regulatory approval and the delivery of product supply for launch, up to an additional $90 million in milestone payments. Arena will sell lorcaserin to Eisai for a purchase price starting at 31.5% of Eisai's annual net product sales, and this price will increase on a tiered basis to as high as 36.5% on the portion of annual net product sales exceeding $750 million. Arena is also eligible to receive $1.16 billion in one-time purchase price adjustment payments based on annual sales levels of lorcaserin and up to an additional $70 million in regulatory and development milestone payments.