Recently published in PNAS, "PROTAC-induced BET protein degradation as a therapy for castration-resistant prostate cancer" uses the Proteolysis-Targeting Chimera (PROTAC) technology developed by Arvinas.

In this PNAS study, they show how their PROTAC-mediated degradation of BRD4 is efficacious against prostate cancer boht in cell culture and in some xenograft mouse models. In their press release, they indicate that this is the first published in vivo data of their PROTAC technology. It must be delivered subcutaneously (or potentially IV) and is not an orally available molecule. In one mouse model, they were able to perform daily dosing. But they note in another of their mouse models that "the lack of tolerance for daily dosing does suggest potentially significant toxic effects," necessitating intermittent dosing schedules.

http://www.ncbi.nlm.nih.gov/pubmed/27274052

This will be interesting to keep an eye on. However, as best as I can tell no PROTAC molecules are in clinical trials yet.

BearDownAZ