There have been, to date, 9,300 scripts written for Xtandi, distributed among 1,600 physicians and 300 institutional acounts. Virtually all of he prescribing physicians are oncologists, rather than urologists. (less than 2% were urologists). Over 90%of oncologists and 81% of urologists were aware of Xtandi. The low number of prescriptions written by urologists was due to the fact that only about 25% of the urologists see post-chemo patients (which is the approved indication for Xtandi). Also urologists are reluctant to prescribe off-label. 98% of Medicare and commercial insurance plans now cover Xtandi.
Schmidt, the Cowen analyst, probably cost his clients a lot of money by floating that report this morning based on a survey which covered only urologists. One of the callers on the CC, David Miller of Biotech Stocks, noted that his organization had conducted a survey of urologists who did see post-chemo patients at ASCO, and that 100% of them had preferred Xtandi to Zytiga.
There is some use of Xtandi in the pre-chemo setting, and the assumption is that almost all of this is among oncologists, who are more ready to prescribe off-label.
The initial detailing for Xtandi was directed at oncologists, who have the vast majority of post-chemo patients. In a short time, Xtandi has 90% awareness and a very high percentage of use among these physicians. By polling urologists, 75% of whom don't even treat post-chemo patients, the Cowen & Co. analyst was missing the point.
An addendum: It was noted that if the PREVAIL trial shows Xtandi to be equal or superior to Zytiga in the pre-chemo setting, there might be another factor which would provide an advantage for Xtandi: All of these patients will presumably eventually undergo treatment with docetaxel, which is administered with prednisone. Since Zytiga, unlike Xtandi, must also be administered wtih prednisone, the patients, mostly older men, would be exposed to prednisone over a longer period than if they were pretreated with Xtandi. Which would mean more bruising, bone weakness, and other side effects.