Amgen's cancer drug combo cut death risk by 58% in lung cancer trial

Amgen $AMGN announced interim Phase 3 results showing that its lung cancer drug Imdelltra, when paired with AstraZeneca $AZN's Imfinzi, cut patients' chances of dying by 58% in extensive-stage small cell disease of the lung. The hazard ratio was 0.42 at a median follow-up of close to 16 months, the company said.

Median overall survival was 21.1 months with the combination, compared with 12.7 months for Imfinzi alone. At one year, close to 80% of patients on the combination were alive, versus 53% on Imfinzi alone. The trial enrolled patients who had completed initial therapy with Imfinzi, platinum-based chemotherapy and etoposide without any disease progression, and it evaluated the combination as their first-line maintenance treatment.

Amgen presented the DeLLphi-305 data on Oct. 24 at the European Society for Medical Oncology Congress and published them in The New England Journal of Medicine. Amgen sponsored the trial, with partial funding and Imfinzi supplied by AstraZeneca. It randomized 563 patients 1:1 to the combination or Imfinzi alone, with overall survival as the primary outcome.

Median progression-free survival was 7.4 months with the combination versus 1.9 months with Imfinzi alone, a 66% reduction in the risk of progression or death. An objective response occurred in 26.4% of patients on the combination and 4.1% on Imfinzi alone. Amgen said survival benefits appeared across prespecified subgroups, including patients with brain or liver metastases.

Grade 3 or higher treatment-related adverse events occurred in 20.9% of patients on the combination and 10.8% of those on Imfinzi alone. Cytokine release syndrome occurred in 49.6% of patients who received Imdelltra, mostly Grade 1 or 2, with one Grade 3 event and none at Grade 4 or higher. Immune effector cell-associated neurotoxicity syndrome occurred in 1.1% of Imdelltra patients, with no Grade 3 or higher events.

"We are moving with urgency to share these results with regulatory authorities worldwide," Jay Bradner, Amgen's executive vice president of research and development, said in a statement. In the U.S., Imdelltra is approved for adults with extensive-stage small cell lung cancer whose disease progressed on or after platinum-based chemotherapy.

The study did not test the combination against other first-line approaches, according to CNBC. Jacob Sands, who is associate chief of Dana-Farber Cancer Institute's Lowe Center for Thoracic Oncology, told CNBC that the 21-month figure "may evolve further and hopefully will substantially improve" with longer follow-up.