Amgen Combination Extends Overall Survival in Lung Cancer Patients to 21.1 Months
Key Facts
Amgen on October 24 announced primary analysis results from the Phase III DeLLphi-305 trial, showing that adding tarlatamab to durvalumab extended median overall survival to 21.1 months, versus 12.7 months with durvalumab alone. The 12-month survival rate was 79.4% in the combination group, compared with 53.3% in the other group, according to presentation slides reported by KOL Pulse. The study tested the treatment as first-line maintenance for patients with extensive-stage small cell lung cancer whose disease had not progressed after induction therapy. This means the results apply to patients whose disease responded or stabilized after initial treatment, and do not describe an alternative treatment for that course. AstraZeneca announced on September 8 that a planned interim analysis showed a statistically and clinically significant improvement in overall survival with the combination compared with durvalumab alone.
The trial included 563 patients who completed durvalumab-based induction therapy and were randomly assigned in a 1:1 ratio to receive tarlatamab with durvalumab or durvalumab alone. It was designed to test the addition of tarlatamab during maintenance after platinum- and etoposide-based chemotherapy with durvalumab. Current standard of care was associated with median overall survival of about one year, according to AstraZeneca, which estimated that around 195,000 people worldwide would receive treatment for extensive-stage disease in 2026. The maintenance results are significant in the context of a disease that relapses rapidly; physician Jacob Sands said many patients relapse quickly and may not reach second-line treatment. Sands described the survival results as "some of the most compelling survival results I have seen."
The gap between the groups also extended to progression-free survival, the time before cancer worsens or death. Median progression-free survival was 7.4 months with the combination, versus 1.9 months with durvalumab alone, while the hazard ratio was 0.34, with a 95% confidence interval of 0.28 to 0.42 and a p-value below 0.001. This result indicates a lower risk of progression or death in the combination group during the study period, with statistical significance according to the presentation. The objective response rate was also 26.4%, versus 4.1%, with a p-value below 0.001. These measures show several aspects of the outcome: continued survival, delayed disease progression and tumor response to treatment.
Susan Galbraith of AstraZeneca said the results showed "unprecedented improvement in overall survival" after durvalumab-based induction therapy followed by maintenance with durvalumab and tarlatamab. In its earlier announcement, Amgen said it had observed no new or unexpected safety signals in DeLLphi-305. AstraZeneca added that safety and tolerability were consistent with the known profiles of the two drugs, with no new safety signals identified. These statements place the efficacy data alongside the safety picture reported by the two companies, without by themselves resolving the regulatory assessment of the use. Amgen had said the results showed a statistically and clinically significant improvement in overall and progression-free survival.
DeLLphi-305 data were presented at the European Society for Medical Oncology (ESMO) Congress, held from October 23 to 27, in a presidential session under abstract number LBA3. Amgen had said detailed data would be presented at an international medical conference and shared with regulators. AstraZeneca also said the data would be presented at a medical meeting and shared with global regulatory authorities. The use tested in the study remains limited to maintenance after induction therapy, while the results alone do not establish a definitive change to the standard of care or regulatory approval for this use. In trading on October 23, Amgen shares closed at $439.26, compared with $447.28 in the previous session.