Amgen built its modern commercial identity on drugs that strengthen bones and suppress immune systems. For years, Prolia and Xgeva, its denosumab franchise, were the kind of steady, recurring revenue that lets a company sleep at night. Then biosimilar competitors arrived, and those two products lost roughly a third of their combined sales in a single quarter. At almost exactly the same moment, Amgen’s newer cardiovascular and respiratory drugs are growing at rates that would have looked implausible five years ago. Two things that should not coexist are coexisting: a business shrinking in one wing and accelerating in another, with a moonshot obesity drug consuming more cash than any program in the company’s history.
The heart of it
The filed numbers show a company successfully replacing eroding legacy revenue with faster-growing newer drugs, while spending at a record pace to bet on a weight-loss therapy that has not yet proven itself in Phase 3. The stock is priced as though that bet lands cleanly, sitting near the top of its own decade-long valuation range. The open question is whether MariTide’s Phase 3 readout, expected in the second half of 2026, would be consistent with a valuation sitting near the 93rd percentile of its decade-long range, a scenario range that depends heavily on both the trial outcome and the durability of the growth drivers.
The year the math changed
The 10-K for fiscal year 2025 shows total revenues of $36.8 billion, up 10% from the prior year. That headline looks solid until you notice what sits below it: R&D spending jumped by more than a fifth in a single year, driven almost entirely by MariTide’s expanding Phase 3 program and early pipeline research. To put that in kitchen-table terms, for every five dollars Amgen earned from selling drugs in 2025, it spent roughly one dollar trying to discover the next ones. That ratio is not unusual for a large biotech, but the pace of increase is the signal worth watching.
The Q2 2026 10-Q, filed August 5, carries the story forward. Total revenues for the quarter reached $10.05 billion, up 10% from the same quarter a year earlier. The growth is real, but it is not evenly distributed, and that unevenness is the whole story.
Two businesses inside one ticker
Six products that Amgen calls its “growth drivers” collectively rose more than a quarter year-over-year in Q2 2026, accounting for nearly 70% of product sales. Repatha, a cholesterol-lowering injection, grew by more than a third. EVENITY, a bone-building drug, grew 38%, and TEZSPIRE, an asthma treatment, grew 42%. These are not niche drugs quietly gaining share; they are becoming the load-bearing pillars of the business.
Running in the opposite direction: Prolia fell 32% year-over-year in the same quarter, and Xgeva dropped 34%, as multiple biosimilar versions of denosumab reached pharmacy shelves. A biosimilar is a near-copy of a biologic drug, approved by the FDA as equivalent, and typically priced well below the original. Enbrel, Amgen’s older rheumatoid arthritis drug, fell not from biosimilars but from the Inflation Reduction Act’s Medicare price-setting mechanism, which took effect January 1, 2026, and cut its net selling price sharply. Otezla also declined meaningfully. The legacy portfolio is contracting faster than a simple headline revenue number reveals.
CEO Robert Bradway, quoted in Amgen’s August 4 press release, described the results as demonstrating “our ability to grow through patent expirations and increased competition.” The filed numbers support that claim for now. Whether the growth drivers can fully absorb the losses as more exclusivities expire through 2027 is the arithmetic that matters most.
The MariTide wager
In 2023, Amgen paid $28.3 billion to acquire Horizon Therapeutics, adding rare-disease drugs to its portfolio. That deal is still digesting on the balance sheet. Now the company is making a second large bet, this one internal: MariTide, its obesity and weight-management drug candidate, is running through six simultaneous global Phase 3 studies covering chronic weight management and cardiovascular conditions. To sharpen that focus, Amgen disclosed in its Q2 earnings that it discontinued AMG 513, an earlier-stage obesity candidate, clearing the runway for MariTide entirely.
On April 28, 2026, Amgen also announced the launch of its Phase 1b STREAM-SCLC trial for small cell lung cancer as part of an FDA pilot program allowing continuous data review, an accelerated path that reflects how seriously regulators are taking real-time trial design. That is a small program today, but it signals where the oncology pipeline is heading.
What the price is assuming
Per BullScope’s valuation dataset [methodology], Amgen’s price-to-sales ratio as of August 2026 sits in the 93rd percentile of its own decade-long range, and its price-to-earnings ratio stands above the company’s ten-year median. The stock has risen sharply over the past twelve months and is sitting near its 52-week high. Following the Q2 report, at least two sell-side firms, Argus and Oppenheimer, raised their valuation estimates, with Argus citing volume growth as the driver. Those figures reflect each firm’s own assumptions and methodology; readers can review the underlying reports directly.
The math, meaning what the filed fundamentals show, is a business growing revenue steadily while spending heavily to replace what biosimilars are taking. The mood, meaning what the market is currently paying, prices in a version of that story where MariTide succeeds and the growth drivers hold. The central analytical tension is the distance between filed fundamentals and current valuation: IF MariTide succeeds and growth drivers hold, the current multiple would appear supported by the arithmetic; IF either assumption proves optimistic, the same arithmetic would point to a narrower range of outcomes than the current price implies.
Reading the numbers
- $36.8 billion (FY2025 revenue, 10-K). What it is: total sales for the full year. What it means here: Amgen has grown its revenue base by roughly 45% since 2020, largely through the Horizon acquisition and organic growth in newer drugs. Everyday version: a business that collected roughly $100 million every day of the year.
- $7.3 billion (FY2025 R&D spend, 10-K). What it is: money spent on research and clinical trials. What it means here: this is 20% of revenue, up 22% in a single year, a sign that the pipeline investment is accelerating faster than the top line. Everyday version: a factory spending one dollar in five on designing next year’s products, and spending more of that each year.
- 32% (Prolia Q2 2026 revenue decline, 10-Q). What it is: the year-over-year drop in sales for Amgen’s bone-loss drug. What it means here: biosimilar competition arrived and took a third of the revenue in one year. Everyday version: a store that sold 100 units last summer now sells 68, because a nearly identical product appeared on the shelf next door at a lower price.
- P/S ratio 6.2, 93rd percentile (BullScope valuation dataset, [methodology], as of August 2026). What it is: the price-to-sales ratio, meaning how many dollars the market pays for each dollar of annual revenue. What it means here: the market is paying more for each dollar of Amgen’s sales than it has in 93% of the past decade’s readings. Everyday version: a house that historically sold for five times its annual rental income is now listed at six times, because buyers expect the rent to rise sharply.
For the standing yardsticks on Amgen: the price tag, the filed record, and the four gauges, refreshed with each edition, see the BullScope Evidence Sheet: Amgen.
Sources
- Amgen 10-Q, quarter ended June 30, 2026 (SEC EDGAR)
- Amgen 10-K, fiscal year ended December 31, 2025 (SEC EDGAR)
- Amgen Q2 2026 press release, August 4, 2026
- Seeking Alpha: Amgen raises 2026 guidance, August 2026
- Seeking Alpha: Amgen and AstraZeneca launch real-time trials, April 2026
- TIKR: Amgen stock and analyst reactions, August 2026
- Insurance Business Magazine: biosimilars and IRA pricing, 2026
