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AstraZeneca's lung cancer immunotherapy trial fails to meet primary endpoint

PBR Staff Writer Published 28 July 2017

AstraZeneca’s Imfinzi (durvalumab) in combination with tremelimumab failed to improve progression-free survival (PFS) significantly in a phase 3 trial in previously untreated patients having advanced lung cancer.

PFS is one of the three primary endpoints in the randomised, open-label, multi-centre, global trial, dubbed MYSTIC, which compared Imfinzi as a monotherapy or in combination with tremelimumab against platinum-based standard-of-care (SoC) chemotherapy in patients with metastatic 1st-line non-small cell lung cancer (NSCLC).

Imfinzi is a human monoclonal antibody that targets PD-L1 and blocks its interaction with PD-1 and CD80 on T cells. Thereby, it counters the immune-evading tactics of the tumour while inducing an immune response.

AstraZeneca said that it believes that Imfinzi as a monotherapy would not have met one of the secondary endpoints which is a pre-specified threshold of PFS benefit compared to SoC. The company had come to a conclusion without having to formally test it.

Despite the setback, AstraZeneca says that it will continue with the MYSTIC trial to measure the remaining two primary endpoints which are overall survival (OS) for Imfinzi as a monotherapy and OS for the Imfinzi-tremelimumab combination.

It expects the final OS data from the two primary endpoints to be registered in the first half of 2018.

AstraZeneca chief medical officer and global medicines development executive vice president Sean Bohen said: “While the results from the MYSTIC trial for progression-free survival in first-line Stage IV non-small cell lung cancer compared with standard of care are disappointing, the trial was designed to assess overall survival and we look forward to evaluating the remaining primary endpoints of overall survival for both mono- and combination therapy.”

In another development, AstraZeneca found success with Tagrisso (osimertinib) which passed a phase 3 trial dubbed FLAURA.

Tagrisso, an irreversible EGFR tyrosine kinase inhibitor, was shown to have significantly improved PFS in lung cancer patients.

Image: AstraZeneca’s lung cancer drug Imfinzi could not improve PFS significantly in a phase 3 trial. Photo: courtesy of AstraZeneca.