Johnson & Johnson's (NYSE:JNJ) drug Zytiga was just approved in a pre-chemotherapy indication for late-stage metastatic castration-resistant prostate cancer. This came as no surprise to investors; it received approval in Europe recently for a first-line therapy as well. In the following video, Motley Fool health-care analyst David Williamson talks about why this wasn't a big needle-mover for Johnson & Johnson share prices, but he also tells us that it was a critical step forward not only for J&J, which wants to see Zytiga hit the $1 billion mark, but also for Dendreon (NASDAQ:DNDN), which is working on some tandem treatment trials with Zytiga and its pre-chemo immunotherapy drug Provenge, that could prove to be huge share price drivers if successful.

David Williamson has no positions in the stocks mentioned above. The Motley Fool owns shares of Dendreon and Johnson & Johnson. Motley Fool newsletter services recommend Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.