Regeneron makes medicines for serious diseases and sells them repeatedly to patients who need ongoing treatment. Its biggest earner is Dupixent, a drug that treats skin conditions, asthma, and other inflammatory diseases. Regeneron does not always sell its drugs directly. Sometimes it shares the profits with partners: Sanofi handles global sales of Dupixent and pays Regeneron its cut, while Bayer sells the eye drugs outside the United States and does the same. This layered arrangement means Regeneron collects money from its own direct sales, from profit-sharing deals, and from royalties paid by others. The diagram below traces where the money goes.
How Regeneron Pharmaceuticals Makes Money
flowchart TD
A["R&D Investment
$5.0B operating cash flow"] --> B["Drug Discovery &
Clinical Development"]
B --> C["Marketed Products
$6.3B net sales"]
B --> D["Collaboration Revenue
$7.3B from partners"]
C -->|"EYLEA HD/EYLEA
$4.4B"| E["Total Revenue
$14.3B"]
D --> E
E --> F["Operating Profit
$3.6B 24.9% margin"]
F --> G["Reinvest in R&D
and Manufacturing"]
G --> A
C --> H["Gross Margin
85.4%"]
H --> F
D -->|"Partnership with
Sanofi & Bayer"| C
Five years of numbers tell a clear story about direction. Revenue peaked at $16.1 billion in 2021, largely because of COVID-19 treatments that have since faded. After that peak, revenue settled and then climbed back steadily: $12.2 billion in 2022, $13.1 billion in 2023, $14.2 billion in 2024, and $14.3 billion in 2025. That is not a company in decline. It is a company that absorbed the loss of a temporary windfall and kept growing anyway.
Regeneron Annual Revenue (2021 to 2025)
Revenue in billions of dollars. The 2021 spike reflects COVID-19 treatment sales that did not repeat. The recovery since 2022 reflects growth in Dupixent and other core medicines.
The profit margins are unusually wide and very stable. Gross margin has stayed between 85% and 87% every year from 2021 through 2025. That means for every dollar of revenue, Regeneron keeps roughly 85 cents after paying to make the product. Operating cash flow has ranged from $4.4 billion to $7.1 billion across those five years. The company carries more cash than debt, with net debt sitting at negative $1.1 billion at the end of 2025, meaning it holds more in cash and investments than it owes in borrowings.
$18.9B
Cash and marketable securities on hand as of December 31, 2025
Dupixent is the engine driving the recovery. Global net product sales of Dupixent reached $17.8 billion in 2025, up from $14.1 billion in 2024 and $11.6 billion in 2023. Regeneron records its share of those profits through the Sanofi collaboration, which contributed $5.9 billion to Regeneron's revenue in 2025 alone. Dupixent accounted for roughly 41% of Regeneron's total revenue that year. A single drug generating that share of income is a concentration risk, but it is also evidence of a drug that keeps finding new patients across new conditions.
What is a biosimilar?
When a drug's patent expires, other companies can make a cheaper copy called a biosimilar. It works the same way but costs less. This is similar to how generic pills work for regular medicines. Once biosimilars enter the market, the original drug usually loses sales quickly as doctors and insurers switch patients to the lower-cost option.
The eye drug franchise tells a more complicated story. EYLEA was Regeneron's original blockbuster, but its U.S. patent expired in May 2024. Multiple biosimilar versions have since launched, and more are expected in the second half of 2026. The result was a 42% drop in EYLEA U.S. sales in 2025. Regeneron's answer is EYLEA HD, a newer, higher-dose version that is harder to copy and offers less frequent injections. EYLEA HD U.S. sales rose to $1.6 billion in 2025, up from $1.2 billion in 2024. But EYLEA HD is not yet large enough to replace what EYLEA is losing.
$2.7B
EYLEA U.S. Sales 2025
$4.8B
EYLEA U.S. Sales 2024
EYLEA U.S. sales fell sharply as biosimilar competition accelerated after the May 2024 patent expiry. EYLEA HD is growing but has not yet closed the gap.
2024
crisis
EYLEA Patent Expiry Opens the Door to Biosimilars
EYLEA's core U.S. patent expired in May 2024, and cheaper biosimilar copies began entering the market. U.S. EYLEA sales dropped 42% in 2025. Regeneron had prepared by launching EYLEA HD, a next-generation version, but the transition is not yet complete and the financial gap between the two products is still wide.
Beyond the immediate products, Regeneron is spending heavily on research. Total research and development expenses reached $5.9 billion in 2025, up from $5.1 billion in 2024 and $4.4 billion in 2023. That is a rising bill. The pipeline includes roughly 45 product candidates in clinical testing across cancer, blood diseases, rare conditions, and neurological disorders. Some of those candidates, like Lynozyfic for multiple myeloma and garetosmab for a rare bone disorder called FOP, are approaching potential approval decisions in 2026.
$5.9B
Research and development expenses in 2025, the highest in the company's five-year reported period
Three specific risks deserve attention. First, the government price pressure is real and escalating. New U.S. laws and executive orders are pushing the government to negotiate lower prices directly with drug companies. EYLEA, EYLEA HD, and Dupixent are all potentially in scope. Lower mandated prices would cut directly into the revenue those drugs generate. Second, Regeneron's manufacturing is concentrated. Its main facilities are in New York and Ireland, plus a small number of outside contractors. A serious problem at any one of those sites could limit supply. In 2025, a manufacturing partner called Catalent received a critical inspection finding from the FDA, which delayed approvals for an EYLEA HD pre-filled syringe and a cancer drug called Ordspono. Third, the Sanofi partnership, while profitable, is also a dependency. Any dispute or breakdown in that relationship could disrupt the Dupixent revenue stream that funds much of what Regeneron does.
Regeneron committed to matching donations to a patient assistance fund for up to $200 million in 2026. This suggests the company sees patient affordability, not just competition, as a real threat to EYLEA and EYLEA HD volumes.
The Bet
Dupixent keeps growing fast enough, across enough new conditions and new countries, to absorb the long-term erosion of EYLEA while also funding the research spending that Regeneron needs to build the next generation of drugs. If Dupixent growth slows, whether from new competing drugs, pricing pressure, or a dispute with Sanofi, the company loses both its primary revenue source and the financial cushion that pays for everything else in the pipeline.
Open question
Regeneron has a strong balance sheet, wide margins, and a drug in Dupixent that keeps expanding into new diseases. But EYLEA is shrinking under biosimilar pressure, research costs are rising every year, and the government is actively working to reduce what drug companies can charge. The pipeline is busy but unproven at scale. Can Dupixent grow fast enough and long enough to cover the EYLEA decline, fund the research bill, and still leave room if drug price controls arrive sooner or hit harder than expected?
Compiled · 10-K · FY2025
Product Revenue Concentration
The company depends heavily on just two eye products: EYLEA HD and EYLEA. In 2025, these two products made up 31% of total company revenue. If sales of these products decline or fail, the company may not stay profitable.
Biosimilar Competition for EYLEA
EYLEA faced major competition after its patent expired in May 2024. Multiple cheaper copycat versions (biosimilars) have been approved, with more expected to launch in the second half of 2026. EYLEA U.S. sales dropped 42% in 2025 due to this competition.
Government Drug Price Controls
New U.S. laws and executive orders are pushing the government and states to negotiate lower drug prices and match prices in other countries. The company may be forced to reduce prices for EYLEA, EYLEA HD, and Dupixent, which could significantly cut revenues.
Dupixent Revenue Dependency
Through a partnership with Sanofi, Dupixent generated 41% of total company revenue in 2025. Growing competition from similar drugs and potential disputes with Sanofi could reduce this revenue stream substantially.
Manufacturing Capacity Constraints
The company relies on limited manufacturing facilities in New York and Ireland, plus contract manufacturers. If these facilities fail or cannot keep up with demand, the company may not be able to supply enough product to meet orders.
10-K Item 1A · Risk Factors
