4-MU

A study of prostate cancer in a mouse model published this month [PMID: 25868577] concludes that "4-MU is an effective nontoxic, oral chemopreventive, and therapeutic agent that targets PCa development, growth, and metastasis by abrogating HA signaling." 4-MU (short for 4-Methylumbelliferone). It is also known as Hymecromone. It works by inhibiting hyaluronic acid.

Regarding the animal studies the researchers said:
"We found that when treatment started early, at eight or 12 weeks it completely inhibited prostate cancer development and growth ...  At 22 weeks, we found small cancers that had stopped growing and even regressed in some cases. Also to our amazement, while 60 percent of the animals in the control group experienced metastasis to distant organs, none in the treatment group developed metastasis. 4-MU did all of this without causing any toxicity to the host." Quoted in this News article

Although success in mice models is far from success in humans if 4-MU were effective for prostate cancer in humans as well, it would have the advantages that:

1. it is already an approved for use in Europe and Asia (in Italy it goes by the name Cantabilin® for biliary applications and is called Cantabiline® in France and Belgium and in other countries by other names).
2. Numerous human trials of 4-MU have been carried out.  See Table; however, these trials were for use in non-cancer applications and safety in cancer applications does not necessarily follow.  For example, if higher doses were required for cancer application at those higher doses there could be additional safety concerns; nevertheless, this is better from the viewpoint of unknown risks than a completely new drug.

A March, 2015 review of 4-MU appears here: [PMID: 25852691]