AstraZeneca's Imfinzi breaks new I-O ground with landmark $1B lung cancer nod

Backed by convincing survival data, AstraZeneca’s Imfinzi is breaking out on its own. Friday, the drug snagged an FDA green light in previously treated, stage 3 lung cancer patients whose tumors can't be removed, a market without a single competitor in sight.

That's an entirely new experience for Imfinzi, the fifth-to-market PD-1/L1 immunotherapy, which faces four other contenders in its only other approved indication, bladder cancer.

With those rivals years away from gaining a similar nod in lung cancer, Imfinzi could hit $1 billion in worldwide sales from that indication alone, Leerink Partners analyst Seamus Fernandez has predicted. Bernstein’s Tim Anderson has estimated that the opportunity in the world's top seven markets tallies about 47,000 patients.

RELATED: ESMO: AstraZeneca wows with Imfinzi's 11-month survival edge in lung cancer

The FDA approved the new use based on phase 3 data showing Imfinzi could stave off disease progression for a whopping 11.2 months longer than chemo achieved, good for a 48% reduction in the risk of disease progression and death. But even before AZ rolled out those numbers at September’s European Society for Medical Oncology (ESMO) annual meeting, its top-line data from that trial, dubbed Pacific, were generating plenty of buzz.

Bernstein’s Anderson, for one, called the trial success a “special kind of surprise,” adding that it shows immuno-oncology “has a place in non-metastatic disease.” The other checkpoint inhibitors are approved only for lung cancers that have spread through the body.

The trial “is the kind of breakthrough that promises to pull upward on the I-O market size,” he wrote to clients in July.

AstraZeneca certainly hopes so. The company is counting on Imfinzi to help it come out of what CEO Pascal Soriot earlier this month called a “really difficult period,” and he ensured investors that there was just one more year to go before “fast growth” sets in.

RELATED: AstraZeneca's Mystic shortfall is an immuno-oncology shake-up for Bristol-Myers and a bolster for Merck and Roche

Plus, in the all-important first-line lung cancer market, Imfinzi’s future is uncertain. After fielding a high-profile trial flop last summer, the British drugmaker is waiting for overall survival data from the Mystic trial, which pairs Imfinzi with its CTLA4 candidate tremelimumab. A loss in that column could not only severely dent Imfinzi’s sales potential, but it could leave AstraZeneca vulnerable to a new takeover attempt from Pfizer, analysts have surmised.

Meanwhile, while AstraZeneca is currently peerless in Imfinzi’s new market, the company has plenty of work to do to help the therapy take off. “A lot of education will be required,” executives said on the company’s Q4 conference call. Still, Oddo BHF analyst Pierre Corby noted to his own clients Tuesday that “we anticipate rapid and significant adoption for Imfinzi in this indication.”