Bayer and Orion Corporation said interim Phase 3 results showed higher four-year metastasis-free survival for patients with very-high-risk, clinically localized prostate cancer assigned darolutamide plus hormone therapy and radiation, versus placebo plus the same therapies.
Four-year metastasis-free survival, measured using conventional imaging, was 95% in the darolutamide group and 88% in the placebo group. The estimated hazard ratio for metastasis or death was 0.42 (95% confidence interval: 0.27 to 0.66; p=0.0001) after a median follow-up of 3.8 years.
The randomized, placebo-controlled DASL-HiCaP trial tested darolutamide at 600 milligrams twice daily for 96 weeks. Both groups received androgen deprivation therapy (ADT) and radiation. Bayer describes ADT with radiation as standard treatment for people at high risk of recurrence, while noting that cancer can still return or spread in this group.
Four-year prostate-specific antigen progression-free survival was 91% with darolutamide and 83% with placebo. Overall survival at four years was 97% and 95%, respectively; the hazard ratio was 0.88, with a 95% confidence interval of 0.49 to 1.59. The companies said follow-up is continuing to assess longer-term outcomes, including overall survival.
Grade 3 or higher adverse events occurred in 43% of patients receiving darolutamide and 36% of those receiving placebo. Bayer said darolutamide is not approved for this treatment setting.
Dr. Tamim Niazi, an associate professor of oncology at McGill University and co-lead investigator, called the interim metastasis-free survival finding a “clear improvement.” The results are scheduled for presentation at the European Society for Medical Oncology Congress on Saturday.
