AstraZeneca announced Monday that it voluntarily withdrew the indication for Imfinzi (durvalumab) in the US for previously treated adults with locally advanced or metastatic bladder cancer. Dave Fredrickson, executive vice president of the company's oncology business unit, called the decision "disappointing," adding "we respect the principles the FDA set out when the accelerated approval pathway was founded."
Imfinzi gained accelerated approval in the US in 2017 based on tumour response rates and duration of response data from the Phase I/II Study 1108. Results from 182 patients with locally advanced or metastatic urothelial carcinoma whose disease progressed after prior platinum-containing chemotherapy showed that Imfinzi had an objective response rate of 17%, regardless of PD-L1 status, and 26.3% in those with PD-L1 high-expressing tumours.
However, continued approval in this indication hinged on results from the Phase III DANUBE trial in the first-line metastatic bladder cancer setting, which AstraZeneca reported last year as having failed to meet its primary endpoints. Specifically, Imfinzi, both as monotherapy and in combination with the anti-CTLA4 antibody tremelimumab, failed to improve overall survival versus standard-of-care chemotherapy.
Imfinzi, which generated sales of $555 million in the fourth quarter of 2020, is approved in a number of indications, including in the curative-intent setting of unresectable, Stage III non-small-cell lung cancer after chemoradiation and extensive stage small-cell lung cancer (SCLC).
AstraZeneca's announcement comes shortly after Bristol Myers Squibb decided to withdraw the SCLC indication for Opdivo (nivolumab) in the US after confirmatory studies failed to show a survival benefit for the PD-1 immune checkpoint inhibitor. Opdivo had been granted FDA accelerated approval in this indication in 2018 based on response rates and duration of response data.
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