On June 2, 2025 Amgen (NASDAQ:AMGN) reported new interim results from the global Phase 3 DeLLphi-304 trial showing IMDELLTRA (tarlatamab-dlle) 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 in patients with small cell lung cancer (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) (Press release, Amgen, JUN 2, 2025, View Source [SID1234653630]). The results will be presented at the 2025 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting (LBA8008) and have been published in The New England Journal of Medicine.
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"Small cell lung cancer is an extraordinarily aggressive and difficult-to-treat disease, and those living with SCLC often experience limited benefit with first line treatment," said Jay Bradner, M.D., executive vice president, Research and Development, at Amgen. "These data underscore IMDELLTRA’s potential to transform patient outcomes and the small cell lung cancer treatment paradigm."
At the planned interim analysis, DeLLphi-304 met its primary OS endpoint and key secondary progression-free survival (PFS) endpoint. Additionally, IMDELLTRA significantly improved patient-reported outcomes (PRO) for cancer-related symptoms of dyspnea and cough compared to the control arm.
"The data from DeLLphi-304 mark a major milestone for people with relapsed small cell lung cancer. Tarlatamab is associated with significant improvements in both overall and progression-free survival over standard chemotherapy in patients with recurrent or progressive disease," said Charles Rudin, M.D., Ph.D., deputy director, Memorial Sloan Kettering Cancer Center. "This study also provides confirmatory data on management of potential toxicities associated with bispecific T-cell engager therapies in a large patient cohort, which is crucial to continuing to improve the experience of patients treated with these medicines."
At a median follow-up of 11.2 months for IMDELLTRA and 11.7 months for the control arm, data from the global Phase 3 DeLLphi-304 clinical trial showed a median OS of 13.6 months with IMDELLTRA compared to 8.3 months with local SOC chemotherapy (HR, 0.60; 95% CI: 0.47, 0.77; P < 0.001). Median PFS was statistically significantly improved for IMDELLTRA compared to local SOC chemotherapy (median PFS: 4.2 vs 3.7 months; HR, 0.71; 95% CI: 0.59, 0.86; P < 0.001).
The safety profile for IMDELLTRA in DeLLphi-304 was consistent with its known profile. In DeLLphi-304, lower rates of grade 3 or higher treatment-related adverse events (TRAEs) occurred with IMDELLTRA versus the control arm (27% vs 62%) and discontinuations due to TRAEs were lower with IMDELLTRA compared to the control arm (3% vs 6%). The most common grade 3 or greater TRAEs were neutropenia (4%) and lymphopenia (4%) with IMDELLTRA and anemia (28%) and neutropenia (22%) with local SOC chemotherapy. Cytokine release syndrome (CRS) with IMDELLTRA primarily occurred after receipt of one of the first two doses and was primarily low grade (42% Grade 1; 13% Grade 2; 1% Grade 3) and manageable. No Grade 4 or Grade 5 CRS events were reported. CRS profiles following the first two doses of IMDELLTRA, including incidence, severity, outcome, time to intervention and time to resolution, were similar among patients who were monitored for 6 to 8 hours (n=43) and those who were monitored for 48 hours (n=209).
DeLLphi-304 is a global Phase 3, randomized, controlled, open-label clinical trial evaluating the efficacy and safety of IMDELLTRA as a treatment for patients living with SCLC who progressed on or after a single line of platinum-based chemotherapy.1 Five hundred and nine patients were randomized to receive either IMDELLTRA or local SOC chemotherapy (topotecan in all countries except Japan; lurbinectedin in the U.S., Canada, Australia, Singapore, Korea; and amrubicin in Japan).1,2 The primary outcome measure of the trial is OS.1 Key secondary outcome measures include PFS and PROs including disease-related symptoms, physical function and quality of life.1 DeLLphi-304 is intended to serve as the confirmatory trial for IMDELLTRA’s accelerated approval for the treatment of adult patients with extensive-stage small cell lung cancer (ES-SCLC) with disease progression on or after platinum-based chemotherapy.
About IMDELLTRA (tarlatamab-dlle)
IMDELLTRA 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.3,4 DLL3 is a protein that is expressed on the surface of SCLC cells in ~85-96% of patients with SCLC, but is minimally expressed on healthy cells, making it an exciting target.5,6
IMDELLTRA (tarlatamab-dlle) U.S. Indication
IMDELLTRA (tarlatamab-dlle) is indicated for the treatment of adult patients with extensive-stage small cell lung cancer (ES-SCLC) with disease progression on or after platinum-based chemotherapy.
This indication is approved under accelerated approval based on overall response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).
About Small Cell Lung Cancer (SCLC)
SCLC is one of the most aggressive and devastating solid tumor malignancies, with a 5-10% five-year relative survival rate across all stages combined.7 SCLC comprises about 15% of the more than 2.4 million patients diagnosed with lung cancer worldwide each year.8-10 Despite initial high response rates to first-line platinum-based chemotherapy, most patients quickly relapse within months and require subsequent treatment options.9
About Tarlatamab Clinical Trials
Amgen’s robust tarlatamab development program includes the DeLLphi clinical trials, which evaluate tarlatamab as a monotherapy and as part of combination regimens, including in both earlier stages of SCLC and earlier lines of treatment.
Tarlatamab is being investigated in multiple studies including DeLLphi-303, a Phase 1b study investigating tarlatamab in combination with standard-of-care therapies in first-line ES-SCLC; DeLLphi-304, a randomized Phase 3 study comparing tarlatamab monotherapy with standard-of-care chemotherapy in second-line treatment of SCLC; DeLLphi-305, a randomized Phase 3 study comparing tarlatamab in combination with durvalumab versus durvalumab alone as first-line maintenance treatment in ES-SCLC; 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 with or without anti-programmed death ligand 1 (PD-L1) in patients with ES-SCLC; and DeLLphi-312, a Phase 3 study evaluating tarlatamab as an induction and maintenance therapy in first-line treatment of ES-SCLC in combination with carboplatin, etoposide, and durvalumab.