Amgen's Mix Has Already Turned. Its Multiple Hasn't Caught Up.

For years Amgen traded as the biotech the market had written off as a bond proxy: eroding blockbusters, heavy debt from the Horizon deal, and a pipeline that skeptics said would never pay for itself. The stock spent much of 2026 as a laggard even as it hugged a record high set in February. The old story is stale. The question is whether the multiple has noticed.

The second-quarter numbers make the turn concrete. Total revenue rose 10% to $10.1 billion, and the six products Amgen now calls its growth drivers grew an aggregate 26% year over year — enough to generate nearly 70% of quarterly product sales. That is the heart of the change: the business is no longer a collection of mature medicines bleeding share to biosimilars and Medicare drug pricing. The growth side now outweighs the erosion, and it is compounding.

Look at where that growth is coming from. Repatha, the cholesterol drug, grew 37% to $953 million. EVENITY climbed 38%. TEZSPIRE rose 42%, Uplizna grew 90%, and the newest franchise, IMDELLTRA, grew 115% year over year to $288 million in the quarter. On the other side of the ledger, the older bone-drug pair Prolia and Xgeva fell 32% and 34% respectively as biosimilars landed, and Enbrel continues to give ground to Medicare Part D drug-price setting. The aggregate product-sales growth of 9% is really a composition story: faster-growing newer drugs now overpower a shrinking legacy base.

IMDELLTRA is becoming a real franchise, not a niche

IMDELLTRA is the piece that most changes the next twelve months. The drug, a bispecific T-cell engager for small cell lung cancer, generated about $627 million across all of 2025. At its current pace it is a genuine growth line on its own. But the bigger news landed on September 8: in the Phase 3 DeLLphi-305 trial, IMDELLTRA combined with AstraZeneca's Imfinzi delivered a statistically significant overall survival benefit in first-line maintenance for extensive-stage small cell lung cancer — the first time a bispecific T-cell engager has shown an overall survival win in that earlier setting.

That matters because it moves IMDELLTRA out of a relatively small late-line niche into the larger first-line pool, which Amgen sizes at up to about 28,000 U.S. patients. Small cell is aggressive, and most patients never make it to second-line treatment, so the earlier a drug is used, the bigger the addressable population. A drug that currently sits at roughly 3% of company sales has a credible path to becoming a meaningful franchise, and it already has three Phase 3 studies pushing it into earlier lines of care.

MariTide is option value, not yet revenue

The drug most investors talk about — MariTide, Amgen's obesity candidate — is a different animal. It is not in the sales numbers at all. It is Phase 3, aiming at a differentiated monthly (rather than weekly) dosing schedule, and the biggest registrational study, OCEAN(a), enrolled more than 7,000 patients quickly, with extension studies testing as few as four to six doses a year. That positioning is the bull case for it. But the obesity market is fiercely competitive, Amgen is the late entrant, and the peak-revenue estimate is far off. Treat MariTide as upside not yet priced or proven, not as part of the current financial bridge.

Free cash flow is the hard proof

This is not about excitement. It is about a business that may soon look a lot harder to dismiss once the free cash flow shows up. Amgen generated $3.5 billion of free cash flow in the second quarter against $1.9 billion a year earlier. One honest caveat: the year-ago quarter was depressed by the final one-time repatriation tax payment, so part of that jump is a cleaner comparison rather than pure momentum. Even so, first-quarter free cash flow was up 50% year over year too. A company that can throw off that much cash while paying down the Horizon-era debt and raising its dividend 6% has a real bridge that a low multiple does not fully credit.

On 2026 non-GAAP earnings guidance of $22.30 to $23.50 per share (raised with the second quarter), the stock at its recent level around the high-$300s works out to only about 16 times forward earnings — a modest multiple for a mix that is still re-accelerating, and one that leaves room if the trajectory keeps compounding.

The bear argument and the line that breaks it

The bears have real ammunition, and it deserves to be stated plainly. Amgen carries roughly $57 billion of debt. The legacy lines are still eroding, and the growth drivers have to keep outrunning that erosion every single quarter. A slowdown in those drivers — or more clinical and regulatory setbacks — would stall the free cash flow story before MariTide ever contributes. The FDA has already been trying to withdraw approval of one Amgen drug, Tavneos, on data-integrity concerns, a reminder that pipeline risk here is more than theoretical.

So the condition that must hold is specific: the growth drivers keep compounding at a double-digit clip while free cash flow keeps expanding year over year. If that holds, the mix keeps getting cleaner and the multiple has room to catch the business. If the drivers decelerate, the debt and the erosion win. The market is still pricing the old risk profile while the operating setup is already getting cleaner. Amgen will only stay this cheap if investors keep looking at the business they remember instead of the one the second quarter actually reported.