Orserdu (Elacestrant)

Orserdu is a hormone‑therapy agent that targets estrogen‑driven breast cancer pathways.

• Estrogen receptor‑positive advanced breast cancer: helps control disease progression in patients with metastatic or locally advanced ER+ tumors.
• Hormone‑resistant disease: provides an oral option when tumors have progressed on prior endocrine therapies.
• Post‑menopausal patients: offers a non‑injectable treatment alternative for eligible women with ER+ disease.

• Elacestrant binds selectively to estrogen receptors (ERα and ERβ) and induces conformational changes that promote receptor ubiquitination and proteasomal degradation. By removing functional ERs, the drug diminishes estrogen‑driven transcriptional activity, thereby inhibiting proliferation of ER‑positive breast cancer cells.

Adverse reactions reported with oral SERDs may vary in frequency and severity.

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Fatigue: general tiredness or lack of energy.
• Diarrhea: loose stools, often transient.
• Hot flashes: sudden feeling of warmth.
• Decreased appetite: reduced desire to eat.
• Musculoskeletal pain: aches in joints or muscles.

Serious or Rare Side Effects

• Liver enzyme elevation: significant increase in ALT/AST.
• Thromboembolic events: deep‑vein thrombosis or pulmonary embolism.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• QT interval prolongation: cardiac conduction changes on ECG.
• Interstitial lung disease: inflammation of lung tissue.
• Hyperglycemia: elevated blood glucose levels.

Patients should be evaluated for safety before starting therapy and monitored throughout treatment.

• Baseline labs: obtain liver function tests and electrolytes prior to initiation.
• Cardiac monitoring: perform ECG if patient has risk factors for QT prolongation.
• Pregnancy: avoid use; drug is contraindicated in pregnancy due to unknown fetal risk.
• Concomitant hormones: assess interactions with other endocrine agents.
• Renal impairment: adjust monitoring in patients with reduced kidney function.
• Store below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Elacestrant may interact with other medicines that affect its metabolism or cardiac safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase elacestrant exposure.
• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce therapeutic levels.
• QT‑prolonging drugs (e.g., sotalol, quinidine): additive risk of cardiac arrhythmia.

Moderate Interactions (Monitor Closely)

• Anticoagulants (e.g., warfarin): may require INR monitoring.
• Hormonal therapies (e.g., tamoxifen): potential pharmacodynamic overlap.
• Statins metabolised by CYP3A4 (e.g., atorvastatin): monitor for increased statin levels.
• Proton pump inhibitors: may modestly affect absorption.
• Herbal supplements (e.g., St St   ---