AstraZeneca reports promising lung cancer results from Phase III immunotherapy drug trial

In Clinical Studies News by Barbara Jacoby

By: Alaric DeArment


The company said Imfinzi and chemotherapy, with or without tremelimumab, extended progression-free survival in first-line non-small cell lung cancer versus chemotherapy, setting up Imfinzi as a potential competitor to Merck’s Keytruda. Overall survival data are expected next year

A British drugmaker’s program to develop an immunotherapy combination for a type lung cancer that could compete with one of the more established drugs for the disease has partially paid off.

London-based AstraZeneca reported positive progression-free survival (PFS) results Monday from its Phase III POSEIDON trial of Imfinzi (durvalumab), tremelimumab and chemotherapy in first-line metastatic non-small cell lung cancer. The company did not disclose full data from the trial, but said it would submit the results for presentation at a future medical meeting and share them with regulators, along with continuing to assess the trial’s other primary endpoint of overall survival (OS), data for which are expected next year.

Imfinzi is a PD-L1 immune checkpoint inhibitor currently approved for treating certain patients with urothelial carcinoma and Stage III unresectable NSCLC after chemoradiation therapy. Merck & Co.’s PD-1 inhibitor, Keytruda (pembrolizumab), is approved for first-line metastatic NSCLC. Tremelimumab is a CTLA-4 inhibitor that is not yet approved; the only approved drug in that class is Bristol-Myers Squibb’s Yervoy (ipilimumab), given with its own PD-1 inhibitor, Opdivo (nivolumab) for melanoma.

POSEIDON enrolled 1,000 patients and randomized them to receive Imfinzi with tremelimumab and one of five platinum-based chemotherapy agents, Imfinzi with chemotherapy or chemotherapy alone, according to The company said the trial showed a statistically significant positive PFS benefit for patients on the doublet and triplet combination over chemotherapy by itself. In addition, the safety of the triplet combination was similar to that of the doublet, with no increased discontinuation of therapy.

AstraZeneca did not say whether the triplet combination outperformed the doublet combination. However, a spokesperson said by telephone that full results of the trial would dive into that, adding via email that results submitted for a future presentation would include further PFS analysis on the doublet and triplet combinations.

“Clinical benefit was observed in a trial population that included a high proportion of patients with squamous disease and multiple choices of chemotherapy regimens,” AstraZeneca executive vice president for oncology research and development Jose Baselga said in a statement. “Additionally, the potential to add tremelimumab to Imfinzi and chemotherapy may present an important treatment approach in this challenging setting, especially taking into consideration the favorable safety profile.”

AstraZeneca’s efforts to expand Imfinzi beyond its current indications and into other lung cancers have hitherto met mixed results. In June, it announced positive results from the Phase III CASPIAN study in extensive-stage small-cell lung cancer, encroaching on turf currently dominated by Roche’s PD-L1 inhibitor, Tecentriq (atezolizumab). However, the NEPTUNE study comparing Imfinzi and tremelimumab as a two-drug combination with chemotherapy in first-line metastatic NSCLC was not successful in extending overall survival.