Numerous studies in pre-clinical models and in human clinical trials have clearly established the potential for the use of rexinoids in the treatment and prevention of cancer. NRX 194204, a second generation rexinoid, is a highly potent and specific activator of RXRs (retinoid X receptors). Because NRX 194204 is significantly more selective for the RXRs relative to the RARs (retinoic acid receptors) than a first generation approved drug, it is associated with fewer adverse events in clinical use. This study seeks to investigate NRX 194204 monotherapy in patients with castration- and taxane- resistant prostate cancer.