The present invention concerns pharmaceutical formulations of ARN-509, which can be administered to a mammal, in particular a human, suffering from an androgen receptor (AR)-related disease or condition, in particular cancer, more in particular prostate cancer, including but not limited to castration-resistant prostate cancer, metastatic castration resistant prostate cancer, chemotherapy-naive metastatic castration resistant prostate cancer, biochemically relapsed hormone sensitive prostate cancer, or high-risk, non-metastatic castration-resistant prostate cancer. In one aspect, these formulations comprise a solid dispersion of ARN-509 and a poly(meth)acrylate copolymer. In one aspect, the solid dispersion of ARN-509 and a poly(meth)acrylate copolymer is obtainable, in particular is obtained, by melt-extruding a mixture comprising ARN-509 and a poly(meth)acrylate copolymer and optionally subsequently milling said melt-extruded mixture. In one aspect, the solid dispersion of ARN-509 and a poly(meth)acrylate copolymer is obtainable, in particular is obtained, by spray drying a mixture comprising ARN-509 and a poly(meth)acrylate copolymer in a suitable solvent.La presente invención se refiere a formulaciones farmacéuticas de ARN-509, que pueden administrarse a un mamífero, en particular a un humano, que sufre de una enfermedad o trastorno relacionado con el receptor andrógeno (AR), en particular cáncer, más en particular cáncer de próstata, incluyendo pero no limitado a cáncer de próstata resistente a la castración, cáncer de próstata resistente a la castración metastático, cáncer de próstata resistente a la castración metastático que no ha tenido quimioterapia, cáncer de próstata sensitivo a hormonas reincidido bioquímicamente o cáncer de próstata resistente a la castración no metastático de alto riesgo； en un aspecto, estas formulaciones comprenden una dispersión sólida de ARN-509 y un copolímero de poli(met)acrilato； en un aspecto, la dispersión sólida de ARN-509 y
