The FTSE 100 drugmaker revealed that its phase III lung cancer trial, called Neptune, had missed its primary endpoint.
Astra had been hoping to show that the combination of two of its oncology drugs, Imfinzi and tremelimumab, was more effective in treating certain lung cancer patients than chemotherapy.
Researchers thought that the combo might be particularly useful in treating people whose tumours had lots of mutations.
But the initial analysis of the data has shown that the drugs weren’t any better than chemo in improving overall survival rates.
José Baselga, Executive Vice President, Oncology R&D said: “We are fully committed to a deep analysis of the vast clinical and biomarker data from this trial to gain further insights to improve Immuno-Oncology approaches for patients with metastatic non-small cell lung cancer.”