Obnyx 40 mg Capsules Obnyx contains Enzalutamide, an androgen receptor signaling inhibitor. It works by blocking androgen binding to androgen receptors, preventing nuclear translocation of the receptor, and inhibiting DNA binding. It is indicated for the treatment of adult men with metastatic and non-metastatic castration-resistant prostate cancer (CRPC) as well as metastatic castration-sensitive prostate cancer (mCSPC).