Sanofi’s Regeneron fix requires extra shot of M&A
SAN•Sanofi agreed to pay Regeneron $1 billion upfront to develop four immune treatments, with up to $7 billion in additional milestone payments. Sanofi’s top-selling drug, Dupixent, is set to lose U.S. patent protection in 2031; its sales are expected to fall by nearly €14 billion over the following four years.
1. Partnership expands
Sanofi agreed to pay Regeneron $1 billion upfront to develop four new immune system treatments, with up to $7 billion more if the experimental drugs reach market. The deal expands a partnership that began in 2003 and also settles litigation between the companies.
2. Patent risk looms
Dupixent, Sanofi’s top-selling drug, accounted for 36% of the company’s nearly €44 billion in 2025 sales and is set to lose U.S. patent protection in 2031. Sanofi’s sales are expected to fall by nearly €14 billion in the four years that follow. The article says Sanofi could borrow an additional €35 billion before its debt-to-EBITDA ratio reached three times.
