Itovebi (Inavolisib)

• Itovebi (Inavolisib) acts on the PI3Kα pathway, which is frequently altered in certain cancers. It is evaluated in clinical settings for the following conditions:
• Advanced PIK3CA‑mutated breast cancer: provides targeted inhibition of PI3Kα to slow tumor progression in patients with metastatic disease.
• Hormone receptor‑positive, HER2‑negative breast cancer with PIK3CA mutation: investigated as part of combination therapy to improve outcomes.
• Other PIK3CA‑mutated solid tumors: studied in clinical trials to assess efficacy across various cancer types.

• Inavolisib selectively binds to the catalytic subunit of the phosphoinositide 3‑kinase alpha (PI3Kα) isoform, preventing its activation. By blocking PI3Kα, downstream AKT phosphorylation is reduced, leading to inhibition of cell growth, survival and proliferation pathways that are commonly up‑regulated in tumors harboring PIK3CA mutations.

Common side effects are generally mild to moderate and reflect the drug’s impact on metabolic and gastrointestinal systems.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Diarrhea: loose stools, often transient.
• Fatigue: reduced energy levels.
• Hyperglycemia: elevated blood sugar levels.
• Rash: skin irritation or redness.
• Decreased appetite: reduced desire to eat.

Serious or Rare Side Effects

• Severe hyperglycemia: may require medical intervention.
• Pneumonitis: inflammation of lung tissue.
• Hepatic enzyme elevation: increased liver function tests.
• Stevens‑Johnson syndrome: severe skin reaction.
• Colitis: inflammation of the colon.
• Interstitial lung disease: serious lung condition.

Before initiating therapy, clinicians should assess baseline health status and monitor specific parameters during treatment.

• Monitor blood glucose: hyperglycemia is a known effect.
• Assess liver function: periodic liver enzyme tests are recommended.
• Watch for infections: immunosuppression may increase risk.
• Evaluate pregnancy status: use only if benefits outweigh risks.
• Cardiac assessment: consider baseline ECG in patients with cardiac history.
• Store at ambient temperature: keep in the original container, protect from moisture.

Inavolisib may interact with other medicines that affect its metabolism or amplify its pharmacologic actions.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole): can increase drug exposure.
• Strong CYP3A4 inducers (e.g., rifampin): may reduce efficacy.
• Antidiabetic agents (e.g., insulin): risk of uncontrolled hyperglycemia.

Moderate Interactions (Monitor Closely)

• Other anticancer agents: potential additive toxicity.
• Anticoagulants (e.g., warfarin): monitor coagulation parameters.
• QT‑prolonging drugs: observe cardiac rhythm.
• CYP3A4 substrate medications: adjust dosing if needed.
• Immunosuppressants: increased infection risk.