Companies · · 2 min read
Editor: Bohdan S.
Amgen’s Imdelltra combo cuts death risk 58% in aggressive lung cancer
Full Phase 3 data show adding Amgen's Imdelltra to AstraZeneca's Imfinzi stretched median survival to 21.1 months, boosting the case for using it earlier.
The short answer
Amgen said on Saturday that adding its drug Imdelltra to AstraZeneca's Imfinzi cut the risk of death by 58% in extensive-stage small cell lung cancer. Median survival reached 21.1 months versus 12.7 months on Imfinzi alone. The data could move Imdelltra into earlier treatment and widen its sales potential.
What happened
Full results from DeLLphi-305, a late-stage trial of 563 patients, were presented at the European Society for Medical Oncology Congress on Saturday. Patients whose cancer had not progressed after first-round chemotherapy and Imfinzi were given either Imfinzi alone or Imfinzi plus Amgen's Imdelltra as ongoing maintenance therapy. The combination lowered the risk of death by 58%, and median overall survival was 21.1 months compared with 12.7 months, CNBC reported. Nearly 80% of patients on both drugs were alive after one year, versus 53% on Imfinzi alone, according to Amgen. In September the company had said only that the trial met its main goal, without giving figures.
What it means
Small cell lung cancer is one of the hardest cancers to treat. Of the over 2.6 million people found to have lung cancer globally every year, roughly 13% to 15% have this form, Amgen said in its September release. Chemotherapy often works at first, but the disease tends to return within months, and only around 40% of patients go on to receive a second line of treatment. That is why moving an effective drug earlier in care matters so much.
Imdelltra works differently from Imfinzi. It latches onto a protein called DLL3 on cancer cells and another called CD3 on T cells, the immune cells that kill tumors, pulling the two together. Imfinzi blocks PD-L1, a protein cancer cells use to hide from the immune system. Combining them attacks the disease from two angles.
Commercially, the result could be significant. Imdelltra is currently approved only for patients whose cancer has progressed on or after platinum chemotherapy. Even so, it generated $627 million in sales in 2025 and $288 million in the second quarter of 2026, up 115% from a year earlier, CNBC reported. A first-line maintenance approval would open the drug to many more patients, since an estimated 60% to 70% of the roughly 31,000 annual US cases are diagnosed at the extensive stage.
There are caveats. The trial compared the combination with Imfinzi alone and did not test it against other first-line approaches. The study hit its main goal at a pre-planned interim analysis, and the lead investigator, Dana-Farber's Dr. Jacob Sands, told CNBC the 21.1-month figure may shift as patients are followed for longer. Amgen said it would share the data with regulators, and approval for the new use is not yet in hand.
The bull case
A 58% cut in the risk of death is unusually large for this disease and could make Imdelltra a standard part of first-line care, potentially turning it into a blockbuster drug with more than $1 billion in yearly sales. Amgen said safety was consistent with each drug's known profile, and the benefit held across patient groups, including those whose cancer had spread to the brain or liver. AstraZeneca could also gain if Imfinzi becomes the standard partner.
The bear case
Regulators still need to approve the new use, and the interim survival figure could shift with longer follow-up. Imdelltra requires monitoring in a healthcare setting after early infusions, which may limit uptake in some clinics. The study did not compare the combination with rival first-line options, leaving room for competitors, and small cell disease accounts for only about 13% to 15% of lung cancer cases, which caps the size of the market.
Why it matters
For investors
Amgen shares could react when trading resumes on Monday, since the data strengthen the outlook for one of its fastest-growing drugs. AstraZeneca may benefit modestly as its Imfinzi is part of the regimen.
The wider context
Advances in hard-to-treat cancers can reshape how drugmakers earn money, and investors who own healthcare stocks through index funds or pensions are exposed to these clinical wins and losses.
Market impact
| Asset (ticker) | Possible move | Timeframe | Why |
|---|---|---|---|
| Amgen (AMGN) | ↑ Up | Short term | Strong survival data widen the potential market for a fast-growing cancer drug. |
| AstraZeneca (AZN) | ↔ Unclear | Long term | Imfinzi gains a stronger partner, but the main upside sits with Amgen. |
| Health Care Select Sector SPDR Fund (XLV) | ↔ Unclear | Short term | One positive trial has limited effect on a broad healthcare index. |
The FinPrism newsroom's view of how these figures could move, as of . It is general news commentary, not a recommendation to buy, sell or hold anything.
Frequently asked questions
What is Imdelltra used for?
Imdelltra, also called tarlatamab, is an Amgen drug for small cell lung cancer. It is currently approved in the US for adults whose extensive-stage disease has progressed on or after platinum-based chemotherapy. New trial data support using it earlier, alongside AstraZeneca's Imfinzi, as maintenance therapy.
How much did Imdelltra improve survival in lung cancer?
In the DeLLphi-305 trial, adding Imdelltra to Imfinzi cut the risk of death by 58%. Median overall survival was 21.1 months versus 12.7 months for Imfinzi alone, and nearly 80% of patients on the combination were alive after one year, against 53%.
How much money does Imdelltra make for Amgen?
Imdelltra brought in $627 million in global sales in 2025 and $288 million in the second quarter of 2026, a 115% jump from a year earlier. Approval for earlier use could push it past $1 billion a year, the threshold for a blockbuster drug.
How this was made: written with AI assistance from the sources listed above, following our editorial standards.
