By Matt Grossman

Merck & Co. Inc. Thursday posted a slightly lower first-quarter profit and nearly flat sales as the Covid-19 pandemic and competitive pressures weighed on its revenue.

The Kenilworth, N.J.-based pharmaceutical company logged earnings of $1.25 a share, a penny lower compared with $1.26 a share in last year's first quarter. Net income attributable to the company ticked down to $3.19 billion, from $3.22 billion a year earlier.

On an adjusted basis, Merck's earnings were $1.40 a share. Analysts polled by FactSet had forecast adjusted earnings of $1.61 a share.

Sales totaled $12.08 billion, up slightly from $12.06 billion in 2020's first quarter. Analysts were expecting revenue of $12.61 billion.

Merck estimated that the Covid-19 pandemic brought a negative impact on its pharmaceutical revenue of $600 million. The segment's revenue was $10.68 billion, roughly in line with its result in last year's first quarter. In addition to the pandemic's negative impact, Merck said its revenue was also negatively affected by the loss of market exclusivity for some products.

Sales of Merck's Keytruda cancer drug grew 19% year over year, but revenue from its Gardasil and Pneumovax vaccines declined by 16% and 33%, respectively.

Animal-health sales grew by 17% to $1.42 billion, a reflection of higher global demand for parasiticides and animal vaccines.

Write to Matt Grossman at matt.grossman@wsj.com

(END) Dow Jones Newswires

04-29-21 0718ET