AstraZeneca has released positive progression-free survival (PFS) results for both Imfinzi (durvalumab) on its own, and in combination with tremelimumab for certain patients with non-small cell lung cancer (NSCLC).

The company announced that the Phase III POSEIDON trial, evaluating the drug in patients with previously-untreated Stage IV (metastatic) strains of the disease, showed statistically significant and clinically meaningful improvement in the final PFS result, compared to chemotherapy alone.

The results also showed that the triple combination of Imfinzi, tremelimumab and chemotherapy demonstrated a similarly significant improvement in PFS, and also did not result in increased discontinuation of therapy.

Clinical benefit was observed in a trial population that included a “high proportion of patients with squamous disease and multiple choices of chemotherapy regimens,” explained José Baselga, executive vice president, Oncology R&D.

The drug is a human monoclonal antibody that binds to PD-L1 and blocks the interaction of PD-L1 with PD-1 and CD80, countering the tumour's immune-evading tactics and releasing the inhibition of immune responses.

“Additionally,” José continued “the potential to add tremelimumab to Imfinzi and chemotherapy may present an important treatment approach in this challenging setting, especially taking into consideration the favourable safety profile.”

The POSEIDON trial is being conducted in 153 centres across 18 countries, including the US, Europe, South America, Asia and South Africa, and will continue to assess the additional primary endpoint of overall survival (OS), with AZ confirmng that data is anticipated in 2020.

Lung cancer is the leading cause of cancer death among both men and women and accounts for about one-fifth of all cancer deaths - broadly split into NSCLC and SCLC, with 80-85% classified as NSCLC. For patients with metastatic variations of the disease, prognosis is particularly poor, as only one in 10 will be alive five years after diagnosis.