Merck & Co bolsters hepatitis C pipeline with Idenix acquisition

US drug firm Merck & Co has agreed to buy hepatitis C specialist Idenix for $3.85 billion (£2.3 billion). The deal gives Merck access to three investigational drug candidates from Idenix’s pipeline, which it hopes will complement treatments being developed in-house.

The most advanced of Idenix’s compounds, samatasvir, inhibits the virus’ non-structural protein 5A, which is involved in replicating viral RNA. It is currently in Phase II clinical trials. The other two, IDX21437 and IDX21459, are nucleotide prodrugs based on uridine, designed to inhibit RNA replication. Both are in Phase I trials.

The high price Merck is willing to pay for these early-stage assets (more than triple the value of Idenix’s shares before the announcement) indicates the company’s confidence in the longevity of the hepatitis C market. It also shows Merck’s desire to compete with the likes of Gilead’s Sovaldi (sofosbuvir), which has made over $2 billion in sales in the first quarter of this year since its approval in December 2013, despite complaints about its high price. The possibility of an all-oral treatment that is effective across the full range of viral genotypes, as well as eliminating the side effects caused by combining drugs with interferon and/or ribavirin is a tantalising goal, but as more drugs are introduced, competition will eat away at the price premium each can charge.