Sanofi-Aventis, the French drugmaker whose $18.5 billion bid for U.S. biotech Genzyme expires on Tuesday, is studying four acquisitions in the ophthalmology sector, Les Echos reported.

The acquisitions are worth €1 billion ($1.36 billion) overall, the French newspaper reported on Monday.

Three of the targets are in the United States and the fourth in Israel, Les Echos said, citing unnamed sources.

"If all these deals come to fruition, the total amount to pay will reach around €1 billion," a source told Les Echos.

"The sum would be spread over three years, as the transactions include initial payments followed by subsequent earn-outs."

A Sanofi spokesman on Monday declined to comment on the report.

If successful, Sanofi would be following Novartis AG , which recently spent $12.9 billion on buying the remainder of U.S.-listed eyecare company Alcon Inc for $12.9 billion, after sweetening its original offer with cash.