U.S. sales of the cocktail, REGEN-COV, approved for emergency use in non-hospitalized COVID-19 patients, were $676.7 million in the third quarter, compared with analysts' estimates of $320.5 million.
The company also recorded additional revenue of $127 million from its collaboration with Roche, which sells the cocktail as Ronapreve outside the United States.
A sharp surge in COVID-19 cases led by the Delta variant caused a "tremendous acceleration" in use of the cocktail, Regeneron Chief Executive Officer Leonard Schleifer had said in August.
Regeneron delivered 300,000 doses of the 1.4 million additional doses that were ordered by the U.S. government in September for $2.94 billion. The company will supply the rest by Jan. 31.
Sales of eczema drug Dupixent, which are recorded by Sanofi, rose 55% to $1.66 billion for the quarter.
Eylea, the company's macular degeneration treatment, reported a 12% rise in sales to $1.47 billion.
Third-quarter revenue jumped 51% to $3.45 billion, while analysts had expected $2.82 billion, according to Refinitiv IBES data.
On an adjusted basis, the company earned $15.37 per share.
Regeneron's shares were up 2.7% before the bell, set to add to the 35% gains recorded so far this year.
(Reporting by Dania Nadeem and Leroy Leo in Bengaluru; Editing by Maju Samuel and Sriraj Kalluvila)
