Regeneron Pharmaceuticals (REGN)

Business Overview

Regeneron's biggest drug is not on its own revenue line. Dupixent, an antibody for eczema and asthma developed with Sanofi, had global net sales of $17.8B in FY2025 (+26% YoY), and Sanofi records them. Regeneron books only its share of the profits on Dupixent and Kevzara, a rheumatoid arthritis drug from the same alliance: $5,242M, or 36.5% of its $14,343M revenue. Dupixent was about 97% of the two products' sales. GAAP net income was $4,505M, and cash and marketable securities were $18.9B at 31 December 2025.

Counting Sanofi's $17.8B as Regeneron's would inflate both Regeneron's sales and how much it appears to depend on Dupixent (see the partnership economics guide). Regeneron generates cash, so runway screens do not apply.

How the Numbers Read

On the profit-share basis, Dupixent is 36.5% of revenue. That is material, but well below Vertex, whose cystic fibrosis drugs are 92.9% of its revenue, or Gilead, where HIV is 70.5% (see the concentration guide).

Eylea, for eye diseases such as wet age-related macular degeneration, is the other leg of the commercial base. US net sales of Eylea HD and Eylea were $4,384.7M in FY2025, down 27% from $5,968.2M in FY2024. R&D was $5,850M, about 41% of revenue. The nearest large pipeline swing outside the Sanofi alliance is olatorepatide, a GLP-1/GIP drug for obesity, with Phase 3 due to start in 2026 (as of January 2026).

Peak-sales targets for Dupixent date quickly. Sanofi's latest, at its Q2 2026 results on 30 July 2026, is around €25B of sales in 2030 at constant exchange rates. It is a target, so anchor on the $5,242M profit share.

Valuation Framework

Build the value in parts: Eylea and the other products Regeneron books itself, plus a DCF on the Dupixent profit share ($5,242M in FY2025, not $17.8B of gross sales), plus the wholly owned pipeline (olatorepatide and other disclosed programmes) weighted by phase success rates at the model's 10.0% discount rate.

Regeneron's antibody discovery platform, VelocImmune mice engineered to make fully human antibodies, produced both Dupixent and Kevzara, so it has shown reuse: it keeps producing approved drugs. That still earns no automatic extra value. Value for undisclosed programmes goes in the model as a stated scenario: how many, at what phase, at what probability.

What to Watch in the Financials

Profit share ($5,242M) against partner sales ($17.8B). Use the profit-share line for Regeneron's concentration and margins. Regeneron's share is of Dupixent's profit after shared costs, so its line does not grow one-for-one with Sanofi's +26%.

Olatorepatide Phase 3 start (2026). Obesity is a crowded field. Give the programme explicit phase probabilities from the rNPV guide; the technology behind it earns no extra credit.

R&D ($5,850M). Watch whether new programmes spread revenue beyond Dupixent and Eylea.

Key Risks

Profit-share concentration (36.5%). It is Regeneron's largest line, so share erosion or rebate pressure on Dupixent hits the $5,242M directly.

Eylea pressure. With US Eylea sales down 27% in FY2025, the commercial base rests on two legs, and either slowing hits group revenue.

Obesity execution. Starting olatorepatide's Phase 3 in 2026 adds clinical risk on top of a partnership-heavy commercial mix.