Ogsiveo (Nirogacestat)

Nirogacestat is a gamma‑secretase inhibitor used in the management of desmoid tumors, a rare fibromatosis condition.

• Desmoid tumor (aggressive fibromatosis): Reduces tumor size and slows disease progression.
• Familial adenomatous polyposis‑associated desmoid disease: Decreases lesion growth and improves symptom control.
• Post‑surgical desmoid recurrence prevention: Delays recurrence after tumor resection.

• Nirogacestat selectively inhibits the gamma‑secretase complex, which is essential for activation of the Notch signaling pathway. By blocking Notch receptor cleavage, the drug reduces transcription of genes that drive fibroblast proliferation and extracellular matrix production, thereby limiting tumor growth in desmoid disease.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Fatigue: generalized tiredness.
• Diarrhea: loose stools, sometimes watery.
• Decreased appetite: reduced desire to eat.

Serious or Rare Side Effects

• Severe infections: opportunistic bacterial or fungal infections.
• Hepatic enzyme elevation: increased ALT/AST indicating liver stress.
• Interstitial lung disease: inflammation of lung tissue.
• Cardiac toxicity: arrhythmias or reduced cardiac function.
• Neutropenia: low neutrophil count increasing infection risk.
• Anaphylactic reactions: severe allergic response requiring immediate care.

Before initiating therapy, clinicians should consider several safety measures.

• Liver monitoring: Perform baseline and periodic liver function tests.
• Infection vigilance: Assess for active infections and advise patients to report fever.
• Cardiac assessment: Evaluate cardiac history and monitor ECG if indicated.
• Pregnancy avoidance: Do not use in pregnant or breastfeeding women unless benefits outweigh risks.
• Gastrointestinal caution: Use carefully in patients with pre‑existing GI disorders.
• Store at ambient temperature: keep in original packaging, protect from moisture and direct sunlight.

Nirogacestat may interact with other medications; awareness of interaction severity is essential.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin): may reduce drug exposure.
• Concurrent QT‑prolonging agents: increase risk of cardiac arrhythmias.
• Other gamma‑secretase inhibitors: additive pharmacologic effects.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inhibitors (e.g., erythromycin): may increase plasma levels.
• Antacids containing aluminum or magnesium: could affect absorption.
• Warfarin: potential alteration of INR, requiring closer monitoring.