Phillip Koo:

So now we're going to sort of move forward into patients who have recurrence. So, we've talked a lot about biochemical recurrence on our PCF webinars. And we've heard about this trial called EMBARK. A lot of excitement around this, it's a big trial, but they had new data they presented at ASCO as well.

And this is something we see often, right? Where you have sort of different ideas or different things that come out of a trial at later time points. So, can you tell us sort of about that process and what we learned at this past meeting at ASCO?

Zachary Klaassen: 

Yeah, absolutely. So, one of our three big meetings, typically either ASCO or ESMO, which is the European equivalent to the American Society Clinical Oncology. And then also the third meeting is GU ASCO, which is just specifically on genitourinary cancer. Those are sort of what we call the big three meetings.

So, as you mentioned, EMBARK was presented now 18 months ago or so as a big plenary session. And then this gets approval. This gets published in the New England Journal Medicine. And then what happens is there's secondary analyses. There's extended follow-up. And so, we see these at subsequent meetings, often for years after the initial presentation.

And so, what they presented at ASCO, I think, it sort of supports this combination of enzalutamide plus Lupron or enzalutamide alone versus ADT. So, it's a three-arm trial. Basically, what this trial showed is if you have high-risk biochemical recurrence, which is a PSA doubling time less than 10 months after a primary treatment, and these patients had conventional imaging, CT scans or MRIs or bone scans, if those were negative, they were considered high risk, non-metastatic.

They were then randomized to one of these three arms. And basically, what this showed 18 months ago is that if you get enzalutamide plus Lupron or enzalutamide alone versus ADT, both of those combinations led to improved metastasis-free survival. And so that was the big outcome, which was presented previously.

What they showed at ASCO, I thought was interesting and why I wanted to bring it up is: No matter what your type of primary therapy was, whether that was surgery alone, radiotherapy alone, surgery followed by radiotherapy, the outcomes were exactly the same. 

So, I think as a urologist who's sitting there seeing patients, that their primary therapy may have been one of those three combinations of surgery, radiation, or surgery and radiation, we know that this EMBARK protocol, which is nine months of treatment, so it's a very specific nine months of enzalutamide plus Lupron or enzalutamide by itself.

And then we see if the PSA goes down to less than 0.2. If that happens at nine months, we give patients a break from treatment and then reinitiate if the PSA starts going up. So, I think this is a nice secondary analysis that tells us that no matter how you got to that biochemical recurrence standpoint where you're high-risk, this is the right treatment for you, regardless of whether you had surgery or radiotherapy.

Phillip Koo: 

Great, so for patients, I guess… the take-home messages are if you have biochemical recurrence, a lot of different options, but if it's high risk, based on a [PSA] doubling time of less than 10 months, really one of these options could improve your outcomes. So be sure to have that conversation with your treating physician.