Use of Xtandi in early stage prostate cancer on top of standard hormone therapy reduces the risk of disease spreading or death by 71 per cent compared with hormone therapy alone, US study results show.
The findings could lead to significantly increased sales of the Pfizer Inc and Astellas Pharma Inc medicine.
The data from a highly anticipated study released on Monday showed that it took 36.6 months for the disease to spread to other parts of the body in patients who received Xtandi plus androgen deprivation therapy (ADT), a measure known as median metastasis-free survival. That compared with 14.7 months for ADT alone, a highly statistically significant difference of nearly two years.
Subjects in the 1400-patient study were deemed at elevated risk of developing metastases in the bones or elsewhere.
"The findings from the trial are quite impressive in terms of delaying the visibility of the cancer," said Dr Maha Hussain, the study's lead investigator who will present the data at a cancer meeting in San Francisco later this week.
She noted that current treatments for this patient population are not life prolonging, so there is a high unmet need for delaying development of metastases and progression to advanced cancer.
"The data is very likely practice changing," added Hussain, from the Robert H Lurie Comprehensive Cancer Center of Northwestern University.
That would be good news for Pfizer and Astellas, providing a lucrative new outlet for Xtandi. The data has been submitted for review to US and European regulators, the companies said.
Xtandi and rival drug Zytiga from Johnson & Johnson are currently approved for advanced cancer that has spread beyond the prostate.
"The treatment opportunities are almost double than the current indication," Pfizer Chief Operating Officer Albert Bourla told Reuters in a recent telephone interview. "And the financial interest is larger because the duration of treatment is longer."
Prostate cancer is the second most common cancer in men worldwide.
