What Is Relugolix (Orgovyx)? FDA Approval, Licensing and Reimbursement in Turkey

 Oral Hormone Therapy for Prostate Cancer

A revolutionary step in prostate cancer treatment, Relugolix (Orgovyx®)is an innovative option intended to improve quality of life, eliminate injections and protect heart health. Its details are presented below.

Drug Profile

 Approved Indications

Relugolix targets the hormone dependence of prostate cancer. FDA-approved uses include:

• Advanced Prostate Cancer: When disease extends beyond the prostate capsule or spreads to distant organs, testosterone must be suppressed to stop tumor growth. Relugolix is a treatment cornerstone in this setting.
• Castration-Sensitive and Resistant Stages: Used while disease remains responsive to hormonal therapy (sensitive), and to continue testosterone suppression even after progression (resistant stage).
• Situations Requiring Urgent Suppression: Because it does not cause a “flare,” it can be started safely in patients at risk of spinal cord compression or with very severe bone pain.

 FDA Approval History

Approval progressed rapidly because of its clinical advantages:

• December 18, 2020 (Official Approval): The FDA approved Orgovyx based on successful HERO results. This was historically significant as prostate cancer's “first oral antagonist.”
• June 3, 2020 (Priority Review): Because of its potential substantial advantages over existing treatments, particularly cardiac safety, the FDA accelerated assessment through “Priority Review.”
• HERO Phase 3 Trial: The trial established the basis for approval, demonstrating faster testosterone reduction than leuprolide (standard injectable treatment) and halving heart attack risk.

 What Is Relugolix and How Does It Work?

Relugolix is a targeted molecule acting on the brain's testosterone “command center,” the pituitary gland.

 Comparison: Relugolix vs. Other Agents

This table summarizes key differences between relugolix (oral antagonist), degarelix (injectable antagonist) and leuprolide (injectable agonist):

 Administration and Dosage

Consistent dosing is essential for full effectiveness:

• Loading Dose (Start): On the first treatment day, to reach effective levels quickly, 360 mg (3 tablets) is taken at once.
• Maintenance Dose (Continuation): From the second day onward, take 120 mg (1 tablet) 1 time each day.
• How Should It Be Taken? Swallow tablets whole; do not break, chew or crush them. As stomach acid and food do not affect them, they may be taken with or without food.
• What If a Dose Is Missed? If fewer than 12 hours have passed since the scheduled dose, take it immediately. If more than 12 hours have passed, skip that dose and resume at the normal time the next day. Never double the dose to compensate.

 Precautions During Use

Pharmacokinetic Properties

The drug's journey through the body:

• Absorption: Rapidly enters the bloodstream after oral dosing, reaching peak blood levels in approximately 1-2 hours.
• Distribution: Rather than circulating freely, 68% is transported bound to proteins (albumin).
• Metabolism (Processing): Broken down by hepatic CYP3A enzymes, so liver activity can affect drug levels.
• Elimination: Most (80%) is excreted in feces, with very little renal excretion (4-5%). This provides patients with renal impairment a major advantage because dose adjustment is unnecessary. The half-life is approximately 25 hours, explaining why daily dosing is sufficient.

 Resistance Mechanisms

Disease may progress despite treatment (castration-resistant stage). Tumor cells may develop these survival routes:

1. Androgen Receptor (AR) Mutations: The tumor changes the shape of testosterone-binding receptors, allowing growth even at very low testosterone levels.
2. Alternative Pathways (Plan B): Tumor cells begin using other signaling pathways, such as PI3K/AKT, instead of testosterone for growth signals.
3. Identity Change (Neuroendocrine Differentiation): Prostate cancer cells may evade treatment by becoming another cell type (neuroendocrine cells) unaffected by hormonal therapy.
4. Drug Efflux: Cells increase “P-glycoprotein” pumps, immediately expelling the drug after entry and eliminating its effect.

 Drug Interactions

 Adverse Effects

Most adverse effects naturally result from testosterone withdrawal (andropause-like effects):

• Very Common:
  • Hot Flushes (54%): Sudden increases in body temperature and sweating episodes. The most common complaint.
  • Fatigue (21%): Reduced energy and weakness.
  • Diarrhea (12%): Generally mild, but should be monitored.
• Other Effects: Reduced libido, muscle-joint pain, weight gain (fat accumulation), breast tenderness or enlargement.
• Serious but Rare Effects: Cardiovascular problems (risk remains despite being lower than with other drugs), ECG changes.

 Special Situations and Precautions

• Fertility (Having Children): This drug stops sperm production. Production may return after discontinuation, but this is not guaranteed. Discuss sperm freezing before treatment.
• Partner Safety: If a partner is pregnant during treatment, the drug may harm the baby. Male patients must use effective contraception during treatment and for a period afterward.
• Bone Health (Osteoporosis): Testosterone keeps bones strong. Prolonged use may increase osteoporosis and fracture risk. Calcium and vitamin D supplementation, with bone density testing when needed, are recommended.