Important clinical trial update with more mature data. Risk of death is 34% lower in combined enzalutamide and LHRH analog versus the latter alone.
In primary analysis, enzalutamide plus androgen deprivation therapy (ADT) improved radiographic progression-free survival (rPFS) in patients with metastatic hormone-sensitive prostate cancer (mHSPC); however, overall survival data were immature. In the phase III, double-blind, global ARCHES trial (ClinicalTrials.gov identifier: NCT02677896), 1,150 patients with mHSPC were randomly assigned 1:1 to enzalutamide (160 mg once daily) plus ADT or placebo plus ADT, stratified by disease volume and prior docetaxel use. Here, we report the final prespecified analysis of overall survival (key secondary end point) and an update on rPFS, other secondary end points, and safety. After unblinding, 180 (31.3%) progression-free patients randomly assigned to placebo plus ADT crossed over to open-label enzalutamide plus ADT. As of May 28, 2021 (median follow-up, 44.6 months), 154 of 574 patients randomly assigned to enzalutamide plus ADT and 202 of 576 patients randomly assigned to placebo plus ADT had died. Enzalutamide plus ADT reduced risk of death by 34% versus placebo plus ADT (median not reached in either group; hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P < .001). Enzalutamide plus ADT continued to improve rPFS and other secondary end points. Adverse events were generally consistent with previous reports of long-term enzalutamide use. In conclusion, enzalutamide plus ADT significantly prolongs survival versus placebo plus ADT in patients with mHSPC.
10-year metastasis-free survival was 71.9% in the short-course ADT group (6 months) and 78% in the long-course ADT group (24 months). So, it seems the longer the duration, the better the outcome. 93% had a Gleason score of 7 or higher.
We know that combination PARP and antiandrogen is better than antiandrogen alone. I have wondered if we need antiancrogen on those patients. This shows that, YES, we do. The combination also was better than PARP inhibitor monotherapy in those patients carrying HRRm.
It might be costly to get the PET scans but helps with prognosis and directing patients to palliative care since positive lesions in all predicts shorter overall survival.
The role for immunotherapy in combination with multitargeted therapy in prostate cancer, for patients who had previous docetaxol, or had visceral disease (liver) showed more benefit from the combination vs. second novel hormonal therapy. Recall that patients who had exposure to docetaxol can be treated with pluvicto. Genomic and genetic testing is encouraged for those patients as PARP targeted mutations can be found (homologous recombination-repair mutations).
SBRT improves PFS in addition to antiandrogen therapy. The question is, with oligomets, do we need systemic therapy in all patients? Or will SBRT be sufficient?
I encourage our FCS radiation oncologists to provide their input on this study, as well.
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