With FDA nod, Pfizer and Astellas’ Xtandi gets its shot at blockbuster sales boost

Pfizer and Astellas have their chance to bring Xtandi to prostate cancer patients before their disease has spread through the body. But it’ll be a mano a mano with Johnson & Johnson, whose rival drug Erleada has a head start, thanks to an earlier-than-expected FDA approval.

The drug, already approved for metastatic disease, nabbed an agency green light Friday for nonmetastatic prostate cancer, a goal Pfizer and Astellas have had squarely in their sights since February, when they unveiled data from their phase 3 Prosper trial.

It’s a key moment for Xtandi—and for Pfizer, because the drug was the centerpiece of its $14 billion Medivation buyout two years ago. Xtandi sales, which had been on an impressive upward trajectory, had started lagging previous growth figures, and with J&J neck and neck with its trials in nonmetastatic disease, market watchers had started questioning whether the deal would pay off as hoped, and executives themselves said the med wasn’t performing up to their own expectations.

But as CFO Frank D’Amelio said when growth began to slow early last year, "as we've said all along, the real critical pivot point for that deal is the nonmetastatic, the earlier stage prostate cancer." And now that’s here.

In its Prosper trial, Xtandi added to standard hormone therapy held off cancer’s spread for a bit more than three years at the median, 21.3 months more than hormone therapy alone could manage. Though Erleada delivered slightly better numbers in its Spartan trial—with a survival advantage over standard therapy of 24 months at the median, 40 months total—analysts said at the time that the numbers were essentially on par.

"We recognize that cross-trial comparisons are fraught with issues, but Spartan and Prosper in our view essentially delivered identical outcomes," Barclays analyst Geoff Meacham, Ph.D., wrote in a note after the data were presented.

Xtandi—which delivered a combined $2.59 billion for Astellas and Pfizer last year—is set to grow to $4.71 billion in 2022, EvaluatePharma has said, putting it among the top 15 best-selling cancer drugs that year, according to data compiled for FiercePharma last year. Barclays predicts that Erleada can peak at $1.3 billion, well within blockbuster territory.

The new indication based on Prosper would be "a significant expansion for the drug," Astellas SVP and oncology chief Steven Benner said in an interview with FiercePharma at the European Society for Medical Oncology meeting last fall. "If it works out as expected, it’s a way to bring Xtandi to a new patient population."

Plus, the drug is also under study in other sub populations that could add to its reach. The partners are running trials two different trials in hormone-sensitive disease, one focused on patients whose cancer has metastasized, called Arches, and the other, dubbed Embark, on patients whose cancer hasn’t yet spread.

"This is an example where we just need to get additional data out that will help show the benefits of Xtandi in additional patient populations," Benner said—and add further to its market potential. The first data from Arches isn’t due until 2020, however, and Embark won’t deliver primary results until 2021, according to ClinicalTrials.gov pages updated last week.

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