Merck antiviral drug Prevymis wins over England's reluctant cost watchdogs

Merck's Prevymis got a flip-flop from England's NICE for recommended placement on the country's NHS. (Merck)

Stinging from an initial rebuff last year, Merck hoped for a turnaround from England’s drug-price watchdog for its antiviral drug Prevymis. And thanks to a discount offer, the drugmaker got exactly that.

After Merck agreed to a confidential price cut, the National Institute for Health and Care Excellence (NICE) recommended Prevymis to prevent reactivation of cytomegalovirus, a common form of herpes, in patients who undergo a blood stem cell transplant.

Between 50% and 80% of U.K. adults are estimated to be infected with CMV, which often lies inactive and causes no symptoms, the company said. But CMV reactivates in about 50% of patients who receive a stem cell transplant because of a compromised immune system.

Prevymis, a once-daily tablet or intravenous therapy, received an initial vote of no confidence from NICE last June. The watchdog cited (PDF) worries about the drug’s price and its ability to help patients live longer.

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Although Prevymis did show promise in preventing the recurrence of CMV, reviewers said its ability to improve mortality rates, compared with placebo, was limited in patients where the virus did come back.

While Merck has yet to report sales after Prevymis’ scheduled launch in December 2018, the drugmaker said it plans to list the 100-day treatment course at $270 per day for the injectable version and $195 per day for the tablet. That puts the cost of treatment at $27,000 and $19,500, respectively. Merck estimated the drug could hit around $370 million in 2020 sales, roughly 1% of the company’s annual pharma revenue.

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Approved by the FDA in November 2017, Prevymis was the first new CMV therapy in 15 years, and it offered some hope for Merck’s flagging virology business. A phase 3 trial showed 38% of Prevymis patients developed CMV at 24 weeks compared with 61% of placebo patients.

Merck's other two antivirals, the HIV fighter Isentress and hep C treatment Zepatier, both saw sales drop last year. In fact, Zepatier took a nosedive.

As patient numbers dwindled and competition increased, Zepatier posted $455 million in global sales in 2018, a 73% drop from 2017’s $1.7 billion. And Zepatier isn't going to recover anytime soon; Merck's expecting further declines, and its Q1 sales bore out those fears. The hepatitis C drug posted just $114 million for the period, down from $131 million for the same period in 2017.