EMBARK Study: Enzalutamide +/- ADT - Fight Prostate Ca...

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EMBARK Study: Enzalutamide +/- ADT

MateoBeach profile image
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Results of the EMBARK study was published this week (10/19/23) in NEJM. It compared high risk BCR PCa treated in 3 groups: Lupron ADT alone. Enzalutamide plus ADT. And Enzalutamide monotherapy. 5 year follow up for metastasis free survival. Results below. Interesting that Enza monotherapy (No ADT) was superior to ADT and nearly as good as the combined treatment.

Details are worth looking at in the full text. Castrate resistance was much lower with combination over ADT as was PSA progression and distant metastasis rates. Enza monotherapy has significant fatigue for many, and significant side effect of gynecomastia as expected with this. (Can be managed by breast radiation or tamoxifen). I don't see where they reported castrate resistance in the monotherapy arm??

This pretty much is the end of ADT monotherapy for the SOC in high risk BCR (or beyond). Those who cannot tolerate enza should pursue the darolutamide as the preferred ARSI in my opinion. Paul/MB

nejm.org/doi/pdf/10.1056/NE...

BACKGROUND

Patients with prostate cancer who have high-risk biochemical recurrence have an increased risk of progression. The efficacy and safety of enzalutamide plus an- drogen-deprivation therapy and enzalutamide monotherapy, as compared with androgen-deprivation therapy alone, are unknown.

METHODS

In this phase 3 trial, we enrolled patients with prostate cancer who had high-risk biochemical recurrence with a prostate-specific antigen doubling time of 9 months or less. Patients were randomly assigned, in a 1:1:1 ratio, to receive enzalutamide (160 mg) daily plus leuprolide every 12 weeks (combination group), placebo plus leuprolide (leuprolide-alone group), or enzalutamide monotherapy (monotherapy group). The primary end point was metastasis-free survival, as assessed by blinded independent central review, in the combination group as compared with the leu- prolide-alone group. A key secondary end point was metastasis-free survival in the monotherapy group as compared with the leuprolide-alone group. Other secondary end points were patient-reported outcomes and safety.

RESULTS

A total of 1068 patients underwent randomization: 355 were assigned to the com- bination group, 358 to the leuprolide-alone group, and 355 to the monotherapy group. The patients were followed for a median of 60.7 months. At 5 years, metas- tasis-free survival was 87.3% (95% confidence interval [CI], 83.0 to 90.6) in the combination group, 71.4% (95% CI, 65.7 to 76.3) in the leuprolide-alone group, and 80.0% (95% CI, 75.0 to 84.1) in the monotherapy group. With respect to metas- tasis-free survival, enzalutamide plus leuprolide was superior to leuprolide alone (hazard ratio for metastasis or death, 0.42; 95% CI, 0.30 to 0.61; P<0.001); enzaluta- mide monotherapy was also superior to leuprolide alone (hazard ratio for metastasis or death, 0.63; 95% CI, 0.46 to 0.87; P=0.005). No new safety signals were observed, with no substantial between-group differences in quality-of-life measures.

CONCLUSIONS

In patients with prostate cancer with high-risk biochemical recurrence, enzalu- tamide plus leuprolide was superior to leuprolide alone with respect to metastasis- free survival; enzalutamide monotherapy was also superior to leuprolide alone. The safety profile of enzalutamide was consistent with that shown in previous clinical studies, with no apparent detrimental effect on quality of life. (Funded by Pfizer and Astellas Pharma; EMBARK ClinicalTrials.gov number, NCT02319837.)

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11 Replies
Papillon2 profile image
Papillon2

Thanks.

PCaWarrior profile image
PCaWarrior

Monotherapy should be over. But it isn't.

Sartor said that over half (I forgot the exact number) the guys who should be using double hormone blockade are on basic ADT.

NPfisherman profile image
NPfisherman in reply to PCaWarrior

I put out a post a while back on how the medical community is failing us.. From 2015-2021, it was 32% of MO's were using doublet therapy, and only 12% of Urologists...The PCF, AUA, and other organizations should be all over this issue...How do we get to a greater than 50% survival rate for 5 years in advanced prostate cancer??

Here's a place to start...long overdue...

Fish

PCaWarrior profile image
PCaWarrior in reply to NPfisherman

My opinion for many of society's ills is education. If the old school doctors were forced to not only register for continuing education but be tested on their knowledge this problem should become less severe.

The latest therapies are a moving target so continuing education is paramount.

pakb profile image
pakb in reply to PCaWarrior

Agree. And urologists should be referring all patients with Pca to oncologists who specialize in Pca before treatment. Seems so many men just continue with urologists and don't see an oncologist.

MateoBeach profile image
MateoBeach in reply to PCaWarrior

Most medical specialty boards now require taking a comprehensive (hard!) recertification test periodically, typically every 7 to 10 years to maintain "Board Certification". However many practice institutions do not require this, so it just gets dropped. We can always ask our doctors "When was the last time you tested and were re-certified in your specialty board?"

MrFireworks profile image
MrFireworks in reply to NPfisherman

Urologists do a lot of things, and may not have the bandwidth to keep up with the fast moving field of PCa treatments.For any other type of cancer, full-time board certified oncologists advise on treatments. Men may get a urologist.

Why do we tolerate this?

NPfisherman profile image
NPfisherman in reply to MrFireworks

Urologists have no excuse... I am on my walk, but I belive Stampede results came out in 2017, which showed the superiority of abiraterone plus ADT to ADT alone...I did a post on the medical community failing us and an update is due... along with vaccine updates review...

Tolerate it... we should never tolerate it... The Dog of Terror and I ALWAYS tell newbies, "Get thee to a Center of Excellence !!!" ... stay with your local urologist and you may have signed your own death warrant...

Fish

KocoPr profile image
KocoPr

Any idea why ENZA mono therapy had more severe fatigue than ENZA+ADT?

pca2004 profile image
pca2004

Hi Paul,

I was interested in the duration of suspension periods.

Starting at week 37 if PSA=5 (no RP) or >=2ng/mL (if RP).

Median suspension: [weighted]

ENZA+ADT: 90.9% for 20.2 months [18.36]

ADT mono: 67.8% for 16.8 months [11.39]

ENZA mono: 85.9% for 11.1 months [9.31] ***

*** due to no T suppression?

-Patrick

MateoBeach profile image
MateoBeach in reply to pca2004

Yes Patrick. If they had an undetectable PSA at week 36 then they could go onto suspended treatment ("vacation"). 91% in the ADT + Enza group suspended for a mean of 20.2 months and were "on" the treatment or 32.4 mo. 44% did not receive Tx for 24 months.

For ADT mono only 68% qualified for suspension which averaged 16.8 months (On treatment 35.4 mo. 32% did not receive Tx for 24 months.

Eza mono was again intermediate: 86% qualified for treatment suspension which averaged 11.1 months. 20.4% did not receive treatment for 24 months. So they had the longest time-on-treatment of 45.9 mo average.

But the other question is how did these hormonal treatments affect emergence of castrate resistance? They formally report this as 3.9% (14/355) for ADT+ E vs 34% for ADT mono. (!) They cannot report it for Enza mono as they could always add Lupron, and these had supra-physiologic Testosterone levels, so do not meet criteria for CR. It is an additional unmeasured possible advantage of ARSI monotherapy as it could be followed with ADT when monotherapy fails.

Another measure is PSA progression which is available for all groups as a proxy for regimen failure: This is 2.3% (8/355) for ADT+E combo; 26% (93/358) for ADT mono; and 10% (37/355) for Enzalutamide monotherapy.

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