5N-Bicalutamide, or 5-azabicalutamide, is a highly potent nonsteroidal antiandrogen (NSAA) which was discovered in 2016. It is a structural modification of bicalutamide differing it from it only by the replacement of a carbon atom with a nitrogen atom in one of its phenyl rings. Similarly to bicalutamide, the drug acts as a selective antagonist of the androgen receptor (AR). However, unlike bicalutamide, it is a reversible covalent antagonist and stays bound to the receptor for a far longer amount of time. As a result of this difference, 5N-bicalutamide has markedly improved potency relative to bicalutamide, with approximately 150-fold higher affinity for the AR (Ki = 0.15 nM versus 22.3 nM) and about 20-fold greater functional inhibition (IC50 = 15 nM versus 310 nM) of the AR. Future stud