Investigator Perspectives on Emerging Concepts in the Management of Genitourinary CancersSTRIVE trial: Enzalutamide versus bicalutamide for men with nonmetastatic or metastatic CRPC
2:43 minutes.
TRANSCRIPTION:
DR GEORGE: I think that’s a fascinating study to me, because all the other studies with enzalutamide had been up against placebo. And one could argue, “Gee. Is that really the standard of care for that population?” And so in using a proven antiandrogen like bicalutamide — in fact, a really related drug from a chemistry perspective — and demonstrating such a dramatic difference in progression-free survival. DR LOVE: Looks like a hazard rate of 0.24. DR GEORGE: It was dramatic, yes, and both for PSA progression as well as for metastasis-free survival. Now, this was not a large Phase III study. That large Phase III study is really against placebo and is ongoing. But this Phase II study looking at both M0 as well as M1 patients, comparing enzalutamide to bicalutamide, I think it really hallmarks just how different these drugs are in their efficacy by just how dramatic we see this delay in this setting. And it’s really largely eliminated bicalutamide from my practice in castrate-resistant prostate cancer patients. No longer do I feel compelled to say, “Let’s start with bicalutamide, and we’ll switch to another agent when that stops working.” I feel comfortable going straight into enzalutamide or abiraterone in that setting, that up-front setting. I don’t need to have them fail a weaker secondary hormonal therapy first. DR LOVE: But now you’re talking about PSA-only disease? DR GEORGE: And this is in patients primarily with castrate-resistant disease. And again, typically in the metastatic setting. For patients who are M0, so no metastatic disease, castrate resistant, we really don’t have therapy indicated in that space. And the reason is because it’s not a life-threatening condition. I mean, these patients don’t die from microscopic disease. And so to me, really, the standard of care is to follow them closely, closely for evidence of metastasis and to pick that up while they’re asymptomatic, because we do have therapies indicated for asymptomatic, low-volume, metastatic castrate-resistant disease. And that to me is still the optimal time to use these agents. This M0 disease state to me is still a little bit of an unproven disease state. It’s not clear to me that that’s one disease state. There could be a mix of microscopic metastatic disease patients, as well as patients who have only localized-only disease recurrence. |