On June 1, 2026 Amgen (NASDAQ:AMGN) reported that the European Commission (EC) has granted marketing authorization for IMDYLLTRA (tarlatamab) as a monotherapy to treat adults with extensive-stage small cell lung cancer (ES-SCLC) who require systemic therapy following disease progression on or after first-line treatment with platinum-based chemotherapy.

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The approval was based on results from DeLLphi-304, the first global Phase 3 trial to demonstrate a significant survival benefit over chemotherapy in this setting.1

"Small cell lung cancer is one of the most aggressive solid tumors, with high rates of relapse following first-line treatment and limited treatment options," said Jean-Charles Soria, senior vice president of Oncology at Amgen. "The European Commission’s approval of IMDYLLTRA, the first and only T-cell engager therapy approved to treat small cell lung cancer, marks an important step forward for patients in Europe and reflects our commitment to advancing innovative medicines that can meaningfully improve outcomes for people living with this devastating disease."

DeLLphi-304, the global Phase 3 clinical trial, demonstrated that IMDYLLTRA reduced the risk of death by 40% and significantly extended median overall survival (OS) by more than five months compared to standard of care (SOC) chemotherapy as a treatment for patients with ES-SCLC who progressed on or after one line of platinum-based chemotherapy (median OS: 13.6 vs. 8.3 months; hazard ratio (HR), 0.60; 95% confidence interval (CI): 0.47, 0.77; P < 0.001).1

"Patients with small cell lung cancer have historically faced a hard road when they progress after initial treatment, surviving only a few months," said Debra Montague, president, Lung Cancer Europe (LuCE). "Approval of a novel treatment option for people in Europe living with this challenging cancer represents meaningful progress and underscores the urgent need for innovation in lung cancer care."

The safety profile for IMDYLLTRA was consistent with its known profile. The most common adverse reactions were cytokine release syndrome (CRS) (56.7%), decreased appetite (36.4%), pyrexia (31.9%), dysgeusia (31.3%), constipation (30.4%), anaemia (30.0%), fatigue (29.8%), nausea (24.9%), asthenia (19.0%), neutropenia (16.9%), hyponatraemia (16.7%), headache (16.3%) and lymphopenia (15.6%). The most common serious adverse reactions were CRS (19.7%) and pyrexia (4.7%).

CRS primarily occurred after the first two doses. As reflected in the Summary of Product Characteristics (SmPC), patients should be monitored from the start of the IMDYLLTRA infusion for 6 to 8 hours on Cycle 1 Day 1 and Cycle 1 Day 8 in an appropriate healthcare setting.2

Amgen’s robust IMDYLLTRA clinical development program includes the DeLLphi clinical trials, which evaluate IMDYLLTRA as a monotherapy and as part of combination regimens, including in both earlier stages of SCLC and earlier lines of treatment.

About the Phase 3 DeLLphi-304 Study
DeLLphi-304 is a global Phase 3, randomized, controlled, open-label clinical trial evaluating the efficacy and safety of IMDYLLTRA as a treatment for patients living with SCLC who progressed on or after one platinum-based chemotherapy regimen. Five hundred and nine patients were randomized to receive either IMDYLLTRA or local standard of care chemotherapy (topotecan in all countries except Japan; lurbinectedin in the U.S., Canada, Australia, Singapore, South Korea; and amrubicin in Japan). The primary outcome measure of the trial is OS. Key secondary outcome measures include progression-free survival (PFS) and patient-reported outcomes (PROs) including disease-related symptoms, physical function, and quality of life.3 Results from DeLLphi-304 were reviewed as a late-breaking presentation at the 2025 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting and simultaneously published in The New England Journal of Medicine.1,4

About IMDELLTRA/IMDYLLTRA (tarlatamab)
IMDYLLTRA is a first-in-class targeted immunotherapy engineered by Amgen researchers to bind to both DLL3 on tumor cells and CD3 on T cells, thereby activating T cells to kill DLL3-expressing SCLC cells. This results in the formation of a cytolytic synapse with lysis of the cancer cell. 5,6 DLL3 is a protein that is expressed on the surface of SCLC cells in up to 96% of patients with SCLC, but is minimally expressed on healthy cells, making it an exciting target.7,8

About Small Cell Lung Cancer (SCLC)  
SCLC is one of the most aggressive and devastating forms of solid tumor cancer. Each year, SCLC accounts for approximately 13-15% of more than 2.4 million cases of lung cancer diagnosed worldwide.9-11 Despite initial high response rates to first-line platinum-based chemotherapy, most patients quickly relapse within months and require subsequent treatment options.10

About Tarlatamab Clinical Trials
Tarlatamab is being investigated in multiple studies including DeLLphi-303, a Phase 1b study investigating tarlatamab in combination with SOC therapies in first-line ES-SCLC; DeLLphi-305, a randomized Phase 3 study comparing tarlatamab in combination with durvalumab vs. durvalumab alone in first-line ES-SCLC in the maintenance setting; DeLLphi-306, a randomized placebo-controlled Phase 3 study of tarlatamab following concurrent chemoradiotherapy in limited-stage SCLC; DeLLphi-308, a Phase 1b study evaluating subcutaneous tarlatamab in second-line or later ES-SCLC; DeLLphi-309, a Phase 2 study evaluating alternative intravenous dosing regimens with tarlatamab in second-line ES-SCLC; DeLLphi-310, a Phase 1b study of tarlatamab in combination with YL201, a B7-H3 targeting antibody drug conjugate, with or without anti-programmed death ligand 1 (PD-L1) in patients with ES-SCLC; DeLLphi-311, a Phase 1b study of tarlatamab in combination with etakafusp alfa (AB248), a novel CD8+ T-cell selective interleukin-2 (IL-2), in patients with ES-SCLC; DeLLphi-312, a randomized Phase 3 study evaluating tarlatamab in combination with carboplatin, etoposide and durvalumab as an induction and maintenance therapy in first-line treatment of ES-SCLC; and DeLLphi-313, a Phase 1b study of tarlatamab in combination with zocilurtatug pelitecan, a DLL3 targeting antibody drug conjugate, with and without a PD-L1 inhibitor in patients with ES-SCLC.12

For more information, please visit www.tarlatamabclinicaltrials.com.

(Press release, Amgen, JUN 1, 2026, View Source [SID1234666296])