> ## Content Index > Fetch the complete content index at: https://bullquill.com/llms.txt > Use this file to discover other available public pages before exploring further. # Amgen lung cancer trial: Imdelltra cuts death risk by 58% - URL: https://bullquill.com/amgen-lung-cancer-trial-survival-results/ - Published: 2026-10-25T00:15:04.000Z - Updated: 2026-10-25T00:26:03.000Z - Description: In 563 patients with extensive-stage small cell lung cancer, median survival was 21.1 months on the combination versus 12.7 months on Imfinzi alone. Serious side effects were about twice as common, at 20.9% versus 10.8%. - Author: Rowan Ashby - Tags: Markets, Trending, Amgen, Imdelltra, Lung Cancer, AstraZeneca, ESMO, #lang-en, #tr-amgen-lung-cancer-trial-survival-results ## Key takeaways - Amgen's Imdelltra (tarlatamab) added to AstraZeneca's Imfinzi (durvalumab) cut the risk of death by 58% versus Imfinzi alone in the Phase 3 DeLLphi-305 trial (hazard ratio 0.42). - Median overall survival was 21.1 months with the combination and 12.7 months with Imfinzi alone, a gain of more than eight months, at a median follow-up of about 16 months. - The trial enrolled 563 patients with extensive-stage small cell lung cancer whose disease had not progressed after first-line chemotherapy plus Imfinzi. - Serious (grade 3 or higher) treatment-related side effects were about twice as common with the combination: 20.9% versus 10.8%. - The data came out on Saturday, 24 October, so Amgen shares (AMGN) can first react when US markets open on Monday, 26 October. In the Phase 3 DeLLphi-305 Amgen lung cancer trial, adding Imdelltra to AstraZeneca's Imfinzi cut the risk of death by 58%. Median survival was 21.1 months versus 12.7 months on Imfinzi alone, according to Amgen's data presented at ESMO in Madrid on 24 October. The results of the DeLLphi-305 study were presented in ESMO's Presidential Symposium (abstract LBA3) and published at the same time in *The New England Journal of Medicine*, Amgen said. The company described the 58% reduction in the risk of death as "unprecedented" for first-line extensive-stage small cell lung cancer (ES-SCLC). AstraZeneca, which partly funded the trial and supplied Imfinzi, released matching figures. ## What the Amgen lung cancer trial showed DeLLphi-305 is a global, randomised, open-label Phase 3 study sponsored by Amgen. It tested Imdelltra as a **maintenance** treatment, meaning it was given after the first round of therapy instead of waiting for the cancer to return. Patients first received the standard induction treatment of platinum chemotherapy, etoposide and Imfinzi. Those whose disease had not progressed were then randomly assigned 1:1 to Imdelltra plus Imfinzi or to Imfinzi alone, until the cancer progressed or side effects became unacceptable. Patients with treated or untreated brain metastases that caused no symptoms were allowed in. The primary goal was overall survival. Secondary goals included progression-free survival and response rate. ### DeLLphi-305 results at a glance | Measure | Imdelltra + Imfinzi | Imfinzi alone | | ---------------------------------------------- | ------------------------- | ------------- | | Patients randomised | 282 | 281 | | Median overall survival | 21.1 months | 12.7 months | | Hazard ratio for death (95% CI) | 0.42 (0.32–0.54), p<0.001 | | | Alive at 12 months | 79% | 53% | | Median progression-free survival | 7.4 months | 1.9 months | | Hazard ratio for progression or death (95% CI) | 0.34 (0.28–0.42), p<0.001 | | | Confirmed objective response rate | 26.4% | 4.1% | | Grade 3+ treatment-related adverse events | 20.9% | 10.8% | | Still on treatment at 7 July 2026 data cut-off | 43.6% | 11.4% | Source: Amgen and AstraZeneca press releases, 24 October 2026; data cut-off date per AstraZeneca. The 58% figure is a **relative** reduction in the risk of death over the follow-up period. It does not mean that 58% more patients were cured. The plainer comparison is the one-year survival rate: 79% of patients on the combination were alive at 12 months, against 53% on Imfinzi alone, according to AstraZeneca. The survival result comes from a planned interim analysis. Specialist outlet OncLive reported that the analysis was triggered at 243 deaths, about 61% of the information planned for the final analysis, and that survival follow-up is continuing. ## Side effects: cytokine release syndrome and neurotoxicity Imdelltra is a bispecific T-cell engager. It binds a protein called DLL3, found on small cell lung cancer cells in about 85–96% of patients, and the CD3 receptor on T cells, so the immune system attacks the tumour. This mechanism can cause cytokine release syndrome (CRS), an inflammatory reaction that is the drug's best-known risk. In DeLLphi-305, CRS occurred in 49.6% of patients on the combination, according to Amgen. Most cases were grade 1 (41.8%). Grade 2 cases made up 7.4%, and one patient (0.4%) had grade 3 CRS. No grade 4 or fatal CRS was reported. The nerve-related side effect known as ICANS occurred in 1.1% of patients, with no grade 3 or higher cases. OncLive reported that 3.2% of patients stopped tarlatamab because of treatment-related side effects. It also reported no treatment-related deaths in the combination arm. Amgen said the safety profile was consistent with what is already known for each drug. Monitoring is also a practical issue for hospitals. In the trial, patients were observed for 1–2 hours after the first two infusions, or 6–8 hours in some regions including Europe, both companies said. On a call with investors, Amgen discussed how monitoring times have been shortened compared with the drug's earlier studies and current US practice, according to a transcript summary published by Investing.com. ## Who is affected: small cell lung cancer in numbers Small cell lung cancer makes up about 15% of lung cancers, and about two-thirds of patients are diagnosed at the extensive stage, when the disease has already spread, according to AstraZeneca. The company estimates that about 195,000 people worldwide will be treated for ES-SCLC in 2026\. Five-year survival after an extensive-stage diagnosis is 3.6%, it said. Dr Jacob Sands of the Dana-Farber Cancer Institute, the trial's international coordinating investigator, said "the magnitude and consistency of benefit in DeLLphi-305 are striking," in AstraZeneca's release. Both companies said the survival benefit held across all prespecified subgroups, including patients with brain or liver metastases. One limit is worth noting. OncLive reported that the 75 patients enrolled in the Americas had a hazard ratio of 0.82 with a wide confidence interval (0.39–1.71). Subgroups that small are not designed to reach firm conclusions, but regulators and doctors will look at them closely. ## What it means for Amgen's oncology pipeline Imdelltra is already approved in the US for adults with ES-SCLC whose disease progressed on or after platinum chemotherapy. That is a second-line use. The European Commission approved the drug, sold there as Imdylltra, for extensive-stage SCLC in June 2026, according to Amgen. DeLLphi-305 is the first Phase 3 trial to test it earlier, in the first-line maintenance setting, where more patients are treated. Amgen said it is "moving with urgency" to share the data with regulators worldwide. It has not given filing dates, and the combination is not yet approved for first-line maintenance in any market. The drug is still small relative to Amgen's total business, but it is growing fast. Imdelltra sales rose 115% year on year to $288 million in the second quarter of 2026, of which $233 million came from the US and $55 million from outside the US, according to Amgen's second-quarter results. Amgen's total product sales in the quarter were $9.54 billion. Amgen also presented other tarlatamab data at ESMO. In the Phase 3 DeLLphi-304 study in previously treated patients, median survival was 13.6 months with tarlatamab versus 8.4 months with chemotherapy after 23 months of follow-up (hazard ratio 0.62). The company has more Phase 3 studies running, including DeLLphi-306 in limited-stage disease and DeLLphi-312, which adds tarlatamab to first-line chemotherapy and Imfinzi. For AstraZeneca, the result supports Imfinzi as the backbone immunotherapy in small cell lung cancer, a point the company made in its own release. ## When markets can react: Monday open The data were presented on a Saturday, so US-listed shares of Amgen (Nasdaq: AMGN) and AstraZeneca (Nasdaq: AZN) have not yet traded on the news. The first regular US session after the release starts at 9:30 a.m. New York time (13:30 UTC) on Monday, 26 October. Shares of AstraZeneca also trade in London and Stockholm. | Amgen (AMGN) close | Price (USD) | Change | | ------------------------- | ----------- | ----------------------------------- | | Friday, 16 October 2026 | 432.49 | — | | Thursday, 22 October 2026 | 447.28 | — | | Friday, 23 October 2026 | 439.26 | −1.8% on the day, +1.6% on the week | Source: Yahoo Finance chart data. Data as of 23 October 2026, 20:00 UTC (US market close). How much of the detailed figures, including the 21.1-month median and the side-effect rates, was already expected by investors will only be clear once trading resumes. The cause of Friday's 1.8% fall in Amgen shares has not been confirmed, and there is no basis to link it to the trial. Investors will also watch for Amgen's third-quarter results; Bullquill could not confirm an official date at the time of writing. ESMO 2026 has already moved other drug stocks this week. Moderna shares fell 17.6% after its [melanoma vaccine data with Merck surfaced early](https://bullquill.com/moderna-merck-shares-fall-melanoma-vaccine-data/). More coverage from the congress is on our [ESMO page](https://bullquill.com/tag/esmo/), and company news is collected on the [Amgen page](https://bullquill.com/tag/amgen/) and in [Markets](https://bullquill.com/markets/). ## What is still unknown - Whether the survival gap holds or changes at the final analysis. - When Amgen will file for the first-line maintenance use, and how fast the FDA and other regulators will act. - Whether monitoring rules for the first doses will change in real-world use outside clinical trials. - How the result will affect Imdelltra sales forecasts. The trial releases did not include any sales outlook. ## Frequently asked questions ### What did Amgen's DeLLphi-305 lung cancer trial show? Adding Imdelltra (tarlatamab) to Imfinzi (durvalumab) maintenance cut the risk of death by 58% (hazard ratio 0.42) compared with Imfinzi alone in 563 patients with extensive-stage small cell lung cancer. Median overall survival was 21.1 months versus 12.7 months, according to Amgen and AstraZeneca. ### What are the side effects of Imdelltra? In DeLLphi-305, cytokine release syndrome occurred in 49.6% of patients on the combination, mostly grade 1, with one grade 3 case and no grade 4 or fatal cases. Grade 3 or higher treatment-related side effects occurred in 20.9% of patients versus 10.8% on Imfinzi alone. ### Is Imdelltra approved for first-line small cell lung cancer? Not yet. In the US, Imdelltra is approved for extensive-stage small cell lung cancer that progressed on or after platinum chemotherapy. Amgen says it will share the DeLLphi-305 data with regulators but has not announced filing dates for first-line maintenance use. ### When can Amgen stock react to the lung cancer trial data? The data were released on Saturday, 24 October 2026, while US markets were closed. The first regular US trading session after the release opens at 9:30 a.m. New York time on Monday, 26 October. Amgen closed at $439.26 on Friday, 23 October. ## Sources - [Amgen: Imdelltra in combination with Imfinzi reduced risk of death by 58% in first-line ES-SCLC (24 Oct 2026)](https://www.amgen.com/newsroom/press-releases/2026/10/imdelltra-in-combination-with-imfinzi-reduced-risk-of-death-by-an-unprecedented-58-in-firstline-extensive-stage-small-cell-lung-cancer?ref=bullquill.com) - [AstraZeneca: Imfinzi plus Imdelltra reduced the risk of death by 58% in the DeLLphi-305 Phase III trial (24 Oct 2026)](https://www.astrazeneca.com/media-centre/press-releases/2026/imfinzi-plus-imdelltra-reduced-the-risk-of-death-by-58-pct-in-1st-line-extensive-stage-small-cell-lung-cancer-in-the-dellphi-305-phase-iii-trial.html?ref=bullquill.com) - [OncLive: DeLLphi-305 data support frontline maintenance tarlatamab plus durvalumab](https://www.onclive.com/view/dellphi-305-data-support-frontline-maintenance-tarlatamab-plus-durvalumab-as-a-new-soc-in-es-sclc?ref=bullquill.com) - [CNBC: Amgen's Imdelltra combo cuts risk of death by 58% in lung cancer (24 Oct 2026)](https://www.cnbc.com/2026/10/24/amgen-imdelltra-lung-cancer-data.html?ref=bullquill.com) - [Investing.com: Amgen at ESMO, investor call transcript](https://www.investing.com/news/transcripts/amgen-at-esmo-imdelltra-data-points-to-earlier-lung-cancer-use-93CH-4970944?ref=bullquill.com) - [ClinicalTrials.gov: DeLLphi-305 (NCT06211036)](https://clinicaltrials.gov/study/NCT06211036?ref=bullquill.com) - [Amgen: Second quarter 2026 financial results](https://www.amgen.com/newsroom/press-releases/2026/08/amgen-reports-second-quarter-2026-financial-results?ref=bullquill.com) - [Amgen: European Commission approves Imdylltra for ES-SCLC (June 2026)](https://www.amgen.com/newsroom/press-releases/2026/06/european-commission-approves-amgens-imdylltra-for-the-treatment-of-extensivestage-small-cell-lung-cancer?ref=bullquill.com) - [Yahoo Finance: Amgen (AMGN)](https://finance.yahoo.com/quote/AMGN/?ref=bullquill.com) This article is for information only and is not investment advice.