(Fixes day of the week in first paragraph)

By Michael Erman

(Reuters) -Merck & Co said on Thursday it expects its 2022 sales to increase as much as 18 percent over last year, mostly on sales of its new COVID-19 pill, molnupiravir.

The drugmaker said sales of the COVID-19 drug were $952 million in the fourth quarter, and it expects another $5 billion to $6 billion in molnupiravir sales in 2022.

Merck developed the antiviral pill – and shares the profits equally – with Ridgeback Biotherapeutics.

Merck Chief Financial Officer Caroline Litchfield said in an interview it is possible molnupiravir sales could top those estimates, which are based on already signed supply agreements for around 10 million treatment courses of the drug.

Merck still expects to produce 30 million treatment courses of molnupiravir by the end of the year, she said.

“Depending on how the pandemic plays out, could there be upside to this?” Litchfield said. “Yes, we’ve got the supply to provide more product to the markets.”

Enthusiasm for the drug, which was once touted as a potential game changer for treating COVID-19, has waned since it was shown to have about 30% efficacy in reducing hospitalizations in its clinical trial. A rival drug from Pfizer Inc had significantly better efficacy results in its trial, but supply of that pill is constrained in the near term.

In the United States, Merck’s drug has been the last choice https://www.reuters.com/business/healthcare-pharmaceuticals/mercks-covid-pill-is-last-choice-us-patients-global-use-varies-2022-01-31 among four available COVID treatment options for at-risk patients. Still, Merck stressed the drug’s success in preventing deaths in its clinical trial – only one patient died among those who received molnupiravir, compared with 9 deaths in the placebo group.

“When we think about the (COVID) death rate in the United States and throughout, having access to medicines that can reduce mortality greater than 80%, 85%, 90% is going to be really important,” Dean Li, Merck’s head of research and development said on a conference call. “Molnupiravir is one of such drugs that can do that. That needs to be emphasized.”

The company said it expects to have supplied all 3.1 million courses of molnupiravir that the U.S. government ordered by the end of this week. The United States paid $2.2 billion – more than $700 a course – for the pills and has the option to order more than 2 million additional courses.

Merck reported fourth-quarter sales of $13.52 billion, up from $10.95 billion a year ago, driven by molnupiravir sales and growth of blockbuster cancer drug Keytruda and human papillomavirus (HPV) vaccine Gardasil. Analysts had expected sales of around $13.2 billion in the quarter.

Merck expects 2022 revenue to be between $56.1 billion and $57.6 billion, up from $48.7 billion last year.

Merck shares were off about 2% in morning trading.

Litchfield said the company plans to reinvest much of the cash from what could be a one-year windfall from molnupiravir in its business and to support business development.

“Our goal is to do meaningful business development. Should that not materialize, we would increase the level of share buybacks that we would do,” she said.

(Reporting by Michael Erman; editing by Richard Pullin and Bill Berkrot)