Locked in a prostate cancer market battle with rival Johnson & Johnson, Pfizer and its partner Astellas have accelerated trial timelines for Xtandi in two studies in patients with hormone-sensitive prostate cancer.
The companies now expect the phase 3 Arches trial, which is testing Xtandi plus androgen deprivation therapy (ADT) versus ADT alone in metastatic HSPC patients, to wrap up at the end of the year, instead of in April 2020 as previously expected.
Another study, Embark, is testing Xtandi plus the hormone therapy leuprolide, compared with Xtandi alone and leuprolide alone in men with high-risk nonmetastatic HSPC. Embark is now expected to finish in mid-2020, compared with a previous estimate of March 2021.
The trial changes come as Pfizer and Astellas face prostate cancer rivals in Johnson & Johnson’s Zytiga and its newer Erleada. In February, J&J’s Erleada secured the FDA’s first-ever nonmetastatic prostate cancer nod. Following up in July, Xtandi won approval in the patient group, setting up the head-to-head duel in the population.
Meanwhile, both rivals hope to expand their treatments to patients with hormone-sensitive prostate cancer. J&J’s Erleada is two phase 3 trials in patients with HSPC, according to ClinicalTrials.gov; they're set to complete in late 2019 and late 2020. Zytiga already boasts a European approval in combo with prednisone or prednisolone in patients with newly-diagnosed high-risk metastatic HSPC.
Astellas SVP and oncology chief Steven Benner previously told FiercePharma the Arches and Embark studies are an “example where we just need to get additional data out that will help show the benefits of Xtandi in additional patient populations."
Xtandi was a key component of Pfizer’s $14 billion buyout of Medivation in 2016. The drug won approval in 2012 to treat metastatic castration-resistant prostate cancer in patients who’ve received docetaxel. For J&J, Zytiga won its initial nod in 2011, and Erleada won a green light this year as the first U.S. drug to treat nonmetastatic, castration-resistant prostate cancer.
Pfizer and Astellas’ Xtandi turned in $2.59 billion in global sales last year. J&J’s Zytiga generated $2.5 billion in global sales.