BioPharma, Pharma

AstraZeneca lung cancer immunotherapy trial fails, dealing blow to company

Data from the Phase III MYSTIC study showed Imfinzi and tremelimumab did not extend survival in first-line NSCLC. AstraZeneca’s shares were down on the news.

A cancer immunotherapy trial by AstraZeneca failed to show improved survival for patients, sending the company’s stock downward.

The British drugmaker said Friday that data from the Phase III MYSTIC study of PD-L1 inhibitor Imfinzi (durvalumab) and the CTLA4 inhibitor tremelimumab did not show an improvement in overall survival among patients with previously untreated metastatic non-small cell lung cancer when compared with platinum-based chemotherapy.

AstraZeneca’s shares opened down 3.5 percent Friday morning on the New York Stock Exchange.

The data showed that among patients in the trial receiving Imfinzi alone, the overall survival result did not reach statistical significance. The combination of Imfinzi with tremelimumab likewise did not show a significant OS improvement.

On the other hand, the company highlighted a potentially favorable hazard ratio of 0.76 among patients receiving Imfinzi alone, adding that the data support further subgroup analysis. “We are encouraged to see that Imfinzi monotherapy activity is in line with that of the anti-PD-1 class in previously untreated patients with Stage IV non-small cell lung cancer; however, we are disappointed that these results missed statistical significance,” AstraZeneca Chief Medical Officer Sean Bohen said in a statement. Stage IV refers to metastatic disease.

Currently, the only checkpoint inhibitor approved for first-line NSCLC is Merck & Co.’s PD-1 inhibitor Keytruda (pembrolizumab), alone or in combination with pemetrexed and platinum chemotherapy. The Food and Drug Administration granted full approval for the combination in August, having given accelerated approval in 2017. Two other checkpoint inhibitors – Bristol-Myers Squibb’s PD-1 inhibitor Opdivo (nivolumab) and Roche’s PD-L1 inhibitor Tecentriq (atezolizumab) – are approved for NSCLC that has progressed during or following chemotherapy treatment. Imfinzi has accelerated approval for urothelial carcinoma.

As such, MYSTIC’s failure is a significant setback for AstraZeneca, effectively taking its drugs out of the running as potential competitors to Keytruda in the large first-line NSCLC space. According to the American Cancer Society, NSCLC accounts for 80-85 percent of lung cancers, while cancers of the lung generally account for around 14 percent of new cancers overall. The organization estimates there will be about 234,030 new cases of lung cancer in the US this year.

Tremelimumab also failed in a Phase IIb study of mesothelioma published in 2017. Bristol-Myers Squibb already has a CTLA4 inhibitor on the market, Yervoy (ipilimumab), approved for treating melanoma, renal cell carcinoma and certain patients with colorectal cancer.

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