TAS-108, also known as SR-16234, is a drug discovered by Masato Tanabe and under development by SRI International and Taiho Pharmaceutical. It is a steroid hormone that has shown signs of treating and preventing breast cancer, even in patients where tamoxifen has failed.[1] [2]
Masato Tanabe's team at SRI has focused on the development of steroid hormones. A compound discovered in a previous SRI contract from the National Institutes of Health showed potential – it acted like "anti-estrogen" in the breasts and uterus but like normal estrogen elsewhere in the body, and was more "tissue-selective".[3] A contract was proposed to Taiho Pharmaceutical in July 1996, and within six years and slightly under $3 million (an unusually short amount of time), two new drugs were discovered and tested on people (particularly people for which tamoxifen has failed): SR-16234 and SR-16287.[3]
The first of those, SR-16234, also inhibited the growth of blood vessels angiogenesis and accelerated the death of cancer cells apoptosis and thus was particularly well suited to be an anti-cancer drug.[3] As of August 2010, the drug had been through five Phase I and two Phase II studies,[4] and Phase III studies are being planned.[5]