Amgen has unveiled promising data from the DeLLphi-305 study, which could position its DLL3-targeting T cell engager Imdelltra (tarlatamab) as a first-line treatment for extensive-stage small cell lung cancer (ES-SCLC) when combined with AstraZeneca's Imfinzi (durvalumab). The study showed a 58% reduced risk of death at 16 months' follow-up, with median overall survival (OS) extending to 21.1 months compared to 12.7 months with Imfinzi alone. Nearly 80% of patients treated with the dual regimen were alive at one year, compared to 53% in the control group, and progression-free survival (PFS) more than tripled to 7.9 months versus 1.9 months.
Jacob Sands of the Dana-Farber Cancer Institute, who presented the results at ESMO, described the findings as 'striking,' noting that the benefit was observed across various patient groups, including those with brain metastases. Sands emphasized the importance of early intervention in a disease where durable survival has been challenging to achieve. The results surpass those of the IMforte trial, which combined Jazz Pharma/PharmaMar's Zepzelca (lurbinectedin) and Roche's Tecentriq (atezolizumab), extending OS by 27% to 13.2 months.
Imdelltra has already become a key product for Amgen, with sales reaching $627 million in 2025, its first full year on the market. Expanding its label to include first-line maintenance could further boost its growth. For AstraZeneca, the data offers the potential to extend the label for Imfinzi, which is currently used in combination with chemotherapy for first-line ES-SCLC and as maintenance therapy for limited-stage SCLC (LS-SCLC).
Dr. Stephen Liu from Georgetown Lombardi Comprehensive Cancer Center highlighted the 'profound' PFS improvement with the dual regimen, calling it 'quite remarkable.' He also pointed to other promising therapies in development, such as anti-B7-H3 antibody-drug conjugates from Roche/MediLink and GSK, which could provide additional treatment options if tarlatamab successfully moves into the first-line space.