AS-601811 is a 5ñ-reductase inhibitor of type 1 of the enzyme which was under development for the treatment of acne, benign prostatic hyperplasia, hirsutism, male-pattern baldness, and prostate cancer but was never marketed. It is taken orally. The drug reached phase 1 clinical trials prior to the discontinuation of its development. It was being developed by Merck Serono.