Merck agrees to buy Afferent Pharmaceuticals in $1.2bn transaction

Afferent develops therapeutic candidates targeting the P2X3 receptor to treat common, poorly-managed, neurogenic conditions.

The agreement gives Merck access to Afferent’s lead investigational candidate, AF-219, which is a selective, non-narcotic, orally-administered P2X3 antagonist currently being investigated in a phase 2b clinical trial to treat refractory, chronic cough.

AF-219 is also being evaluated in a phase 2 study in idiopathic pulmonary fibrosis (IPF) with cough.

Under the deal, Merck will purchase all outstanding shares of Afferent for an upfront fee of $500m, and could pay an extra $750m tied to several clinical development and commercial milestones.

The transaction is expected to close in the third quarter of this year, subject to several conditions.

Merck Research Laboratories president Roger Perlmutter said: "Afferent has pioneered the clinical development of novel investigational candidates selectively targeting the P2X3 receptor, an exciting area of research.

"We look forward to advancing these innovative molecules for patients with conditions like chronic cough, an area of significant unmet medical need."

In a separate development, a US Food and Drug Administration advisory panel has backed approval of Merck’s Zinplava (bezlotoxumab), an investigational agent for prevention of Clostridium difficile infection recurrence.

The Antimicrobial Drugs Advisory Committee agreed, with a vote of 10 to five, that Merck has provided enough data of the safety and effectiveness in its proposed indication.