Abstract
Relugolix is a novel orally administered gonadotropin-releasing hormone (GnRH) antagonist approved for androgen deprivation therapy (ADT) in advanced prostate cancer. Its oral formulation, rapid onset of action, and potentially improved cardiovascular safety profile distinguish it from traditional injectable GnRH antagonists. This review evaluates current primary research on the clinical effectiveness and safety of Relugolix compared to established ADT agents. A structured literature search was conducted using PubMed, targeting primary research articles that assessed the efficacy and safety of oral Relugolix. Inclusion criteria comprised original studies with clinical endpoints such as testosterone suppression, prostate-specific antigen (PSA) response, and castration resistance-free survival (CRFS). Exclusion criteria included reviews, meta-analyses, and studies not investigating Relugolix. Searches were completed by two independent reviewers compared following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Nine primary studies met the inclusion criteria, including randomized controlled trials (RCTs), subgroup analyses, pharmacokinetic modelling, and observational studies. In the HERO trial, Relugolix achieved castration-level testosterone (<50 ng/dL) in 96.7% of patients, outperforming Leuprolide (88.3%) in both speed (median = 4 days vs. 29 days) and magnitude of suppression. Subgroup analyses demonstrated consistent efficacy across patients receiving concomitant therapies with a lower incidence of major cardiovascular events in the Relugolix group. Additional studies confirmed its effectiveness when combined with radiotherapy in comparison with Degarelix. Pharmacokinetic modelling supported rapid and sustained testosterone suppression even during short treatment interruptions. Relugolix is an effective and well-tolerated oral GnRH antagonist for patients with advanced prostate cancer. It offers rapid testosterone suppression, high rates of CRFS, and a potentially favorable cardiovascular safety profile compared to injectable ADT agents. These advantages, along with oral administration, support its use as a viable alternative in clinical practice. Further long-term studies are warranted to confirm sustained outcomes and optimize treatment regimes.