In this video, health-care analyst David Williamson takes a closer look at two of the recent European Medicines Agency opinions -- one positive and one negative, even though both drugs have U.S. approval. Watch and find out what it means for Medivation investors and its competitors Johnson & Johnson and Dendreon now that metastatic prostate cancer drug Xtandi received a big thumbs-up from the agency. On the other side of the coin, Pfizer's first-in-class JAK-3 inhibitor for rheumatoid arthritis was knocked on both safety and efficacy, getting hit with a negative opinion. Pfizer's loss may be AbbVie's gain, as its injected best-selling RA drug, Humira, won't have to face an oral competitor.