Merck & Co. has agreed to acquire Afferent Pharmaceuticals, a privately held pharmaceutical company, in a deal valued up to $1.25 billion. Afferent Pharmaceuticals is developing therapeutic candidates targeting the P2X3 receptor for the treatment of common, poorly managed, neurogenic conditions.

Afferent's lead investigational candidate, AF-219, is a selective, non-narcotic, orally-administered P2X3 antagonist currently being evaluated in a Phase IIb clinical trial for the treatment of refractory, chronic cough as well as in a Phase II clinical trial in idiopathic pulmonary fibrosis  with cough.

Under the agreement, Merck, through a subsidiary, will acquire all outstanding stock of Afferent in exchange for an upfront payment of $500 million in cash. Also, Afferent shareholders will be eligible to receive a total of up to an additional $750 million associated with the attainment of certain clinical development and commercial milestones for multiple indications and candidates, including AF-219.

Afferent's clinical candidates, AF-219 and AF-130, are orally available investigational candidates that selectively block P2X3 receptors. P2X3 receptors are believed to play a key role in the sensitization of certain sensory nerves, notably C-fiber afferents. These nerves become activated and sensitized under pathological conditions mediated by a common cellular signal, ATP, when it is released in high concentrations due to cellular distress following injury or infection. Afferent's compounds are designed to selectively block ATP activation of P2X3 channels, potentially reducing a range of sensory signs and symptoms.

The closing of the transaction will be subject to certain conditions, including the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act and other customary conditions. The companies anticipate the transaction will close in the third quarter of 2016. ,/p>

Source: Merck & Co.