A matter of definition. I can argue that it's a bone oriented therapy with anti cancer activity, so the more accurate title would be an "anti bone metastases" drug : "About Alpharadin...This compound mimics many of the behaviors of calcium in the bone." (http://www.bayer.com/en/news-detail.aspx?newsid=14775). Anyway, my point was about a bone targeted therapy in cancer that can benefit OS.
Xgreva is different.
Agree. Still, Xgreva inhibits bone turnover so it's a pure "bone" drug by it's mechanism, but it can impact OS in CRPC patients, which makes it an "anti cancer" therapy as well.