Sanofi (SNY): A Bull Case Theory

Ricardo Pillai

Tue, May 13, 2025, 8:15 AM 4 min read

We came across a bullish thesis on Sanofi (SNY) on Substack by Business Model Mastery. In this article, we will summarize the bulls’ thesis on SNY. Sanofi (SNY)'s share was trading at $51.06 as of May 12^th. SNY’s trailing and forward P/E were 18.19 and 10.81 respectively according to Yahoo Finance.

A biopharmaceutical research laboratory filled with scientists, illuminated by the glow of their equipment.

Sanofi has engineered one of the most defensible pharmaceutical businesses in the world, anchored by a single drug that now fuels over 30% of its pharmaceutical revenue and powers a growing immunology empire across 11 disease areas. The centerpiece of this engine is Dupixent—a molecule that has transcended its original indication to become a €20 billion opportunity, with sales growing 33.9% year-over-year at constant exchange rates in 2024. Far from a conventional blockbuster, Dupixent targets the Type 2 inflammation pathway, a mechanism implicated across multiple chronic immune diseases. That broad biological applicability has allowed it to scale across atopic dermatitis, asthma, eosinophilic esophagitis, and more, with new indications still being added. Each regulatory approval deepens its reach and compounds its growth trajectory, effectively transforming the molecule into a platform asset.

This success is supported by Sanofi’s in-house biologics manufacturing network—an integrated moat that ensures control over quality, cost, and IP. With state-of-the-art facilities across France, Belgium, the U.S., and a new modular hub in Singapore, Sanofi avoids outsourcing and builds resilience against global supply chain volatility. This infrastructure supports not only Dupixent but a growing pipeline of monoclonals, including RSV treatments and oncology candidates. The vaccine business adds a second foundational pillar, with more than €7 billion in sales in 2024. Beyfortus, an RSV monoclonal developed in partnership with AstraZeneca, delivered a staggering €1.49 billion in its first year. Meanwhile, flu vaccines—anchored by deep public-sector distribution—generated €2.25 billion, and MenQuadfi, a meningitis vaccine, posted 50.5% growth.

Despite some expected erosion in older General Medicines—down 4.8% due to pricing pressure and generic competition—the Specialty Care segment is more than compensating, growing 8.7% in 2024 and now contributing over half of pharma revenues. Rare disease products like Myozyme, Cerezyme, and Aldurazyme continue to generate steady revenue streams due to long-term, genetically-driven treatments where patient switching is rare and risky. Consumer Healthcare, often overlooked, contributed over €4 billion with stable 4.8% growth, led by brands like Allegra and Dulcolax. This segment’s defensive characteristics—brand loyalty, regulatory insulation, and pricing power—make it a ballast during economic turbulence. Notably, it has been structurally carved out, giving Sanofi optionality for an IPO or spin-off.