The FDA has granted breakthrough status to AstraZeneca’s PD-L1 inhibitor Imfinzi in an early-stage form of lung cancer, sparking a rise in its share price.
The modest increase came on the back of dramatic share reductions last week however, AZ reported that Imfinzi (durvalumab) had failed to meet its objectives in the MYSTIC trial involving patients with more advanced non-small cell lung cancer (NSCLC), denting its hopes of turning the drug into a $6.5bn blockbuster.
The US regulator gave the breakthrough designation to Imfinzi as a treatment for patients with locally-advanced NSCLC that cannot be treated surgically and has not progressed after platinum-based chemoradiation therapy.
Sean Bohen, AZ’s chief medical officer, said that for these patients “the only current option is active monitoring [but] unfortunately for the majority of patients their cancer will progress to metastatic disease, typically within 12 months”.
He said that Imfinzi is the first of the immuno-oncology therapies to show a significant benefit in this earlier (stage III) form of NSCLC, where patients’ tumours have not yet spread (metastasized) to other parts of the body.
If approved, Imfinzi could grab a slice of the NSCLC monotherapy market currently unaddressed by rival checkpoint inhibitors such as Bristol-Myers Squibb’s Opdivo (nivolumab), Merck & Co’s Keytruda (pembrolizumab) and Roche’s Tecentriq (atezolizumab), that some analysts have predicted could be worth $1.75bn or more.
The new status – which gives Imfinzi a quicker route through the regulatory process – comes on the back of data from the phase III PACIFIC trial reported in May, which showed that AZ’s drug was able to achieve a statistically-significant increase in progression-free survival (PFS) compared to placebo.
It is estimated that there were around 100,000 stage III NSCLC patients in the G7 countries in 2016 – around a third of the total incidence of this form of lung cancer, with around half of that group having tumours that were not amenable to surgery.
AZ was awarded accelerated approval by the FDA for Imfinzi in previously-treated patients with advanced bladder cancer in May, pulling in just $1m in sales in the first half according to AZ’s results announcement.
The company said last week that it would continue the MYSTIC trial in the hope that Imfinzi – either alone or in combination with AZ’s CTLA4 inhibitor tremelimumab – could show a benefit on overall survival.
The news comes after AZ’s chief executive Pascal Soriot re-affirmed his commitment to the company despite a rumoured move to Teva, saying he intends to stay at least until the company’s flagship new headquarters and R&D campus in Cambridge opens – something that is scheduled to occur towards the end of next year, after the outcome of the MYSTIC trial is known.
He also said that AZ had decided to put any new capital investment decision on hold in the UK until the outcome of the Brexit negotiations becomes clearer – including a £120m expansion of a facility in Macclesfield intended to support high demand for prostate cancer drug Zoladex.