The French drugmaker said it expected the bump to its profits and sales from the pandemic to fade in the second quarter. There are currently no approved treatments or vaccines specifically for COVID-19, the respiratory disease caused by the new coronavirus.

Shares in Sanofi were down 0.8% in mid-morning trading.

The S&P 500 and the Nasdaq turned negative at the close on Thursday after a report that Gilead Sciences antiviral drug remdesivir had failed to help severely ill COVID-19 patients in its first clinical trial.

Sanofi is working on two vaccines projects, one of which is in partnership with GlaxoSmithKline, and is engaged in multiple clinical trials to evaluate the response to COVID-19 of two treatments already approved for other diseases.

Sanofi has also started preliminary work with U.S startup Luminostics to develop an app that will allow people to test themselves for the virus.

Hopes for tackling the virus, which has killed thousands and infected over 2 million people so far, have been focused on developing a vaccine but Sanofi has said a vaccine, if development meets expectations, will not be ready until 2021.

Roche Chief Executive Severin Schwan called current projected timelines of 12-18 months for COVID-19 vaccines ambitious.

"There is less concern about finding a sucessful vaccine than there is about making the volumes needed," Sanofi's CEO Paul Hudson told reporters.

"The biggest untold story in Europe right now is the one about number of doses, not number of vaccines."

The company is receiving financial support from the U.S government for one of its vaccines project but has so far declined to say how much it was spending on its coronavirus vaccines efforts as a whole.

Johnson & Johnson announced a $1 billion deal with the U.S. administration on March 30 to create enough manufacturing capacity to make more than 1 billion doses of a vaccine.

The arrangement is part of the federal government's effort to encourage drugmakers to be able to produce massive amounts of COVID-19 vaccines even before any are proven to work.

David Loew, executive vice president with Sanofi's vaccines unit, told Reuters last week Sanofi was working with risks as it gears up for mass production.

The company is hoping to be able to produce over 1 billion doses of the vaccine it is working on with GSK in a year while it is contemplating the possibility of extending production capacity for another vaccine canditate currently in development with U.S. company Translate Bio.

Sanofi's net income was up 16.1% at constant exchange rates in the first quarter to 2.04 billion euros (1.78 billion pounds)while sales rose 6.6% to 8.97 billion. The company said around half of the growth in sales and profit was attributable to the coronavirus pandemic.

Specialty care revenue, which includes the performance of Sanofi's star eczema treatment Dupixent, was up 31.3%. Sales of consumer healthcare products were up 4.2% with painkillers Doliprane and Buscopan leading the way.

In February, Sanofi said it was targeting a rise of around 5% in earnings per share this year.

By Matthias Blamont