Indications:

Treatment of hormone receptor (HR)-positive, HER2-negative locally advanced or metastatic breast cancer with specific PIK3CA/AKT1/PTEN alterations, in combination with fulvestrant, after progression on endocrine-based therapy.

Dosage & Administration

Standard Dose:

            ●    160 mg (two 80 mg tablets) taken orally twice daily (morning and evening, ~12 hours apart).

            ●    Treatment schedule: 4 days on, 3 days off (e.g., take Monday–Thursday, skip Friday–Sunday).

            ●    Take with food to improve absorption (avoid grapefruit/seville oranges).

            ●    Swallow whole—do not crush, split, or chew.

Missed Dose:

            ●    If a dose is missed by ≤4 hours, take it as soon as possible.

            ●    If >4 hours late, skip the dose and resume the next scheduled dose.

            ●    Do not double dose.

Dose Modifications:

            ●    Severe side effects may require dose reduction to 120 mg or 80 mg twice daily or temporary interruption.

Precautions

1. Hyperglycemia (High Blood Sugar)

            ●    Monitor blood glucose before starting and regularly during treatment.

            ●    May require antidiabetic medications (e.g., metformin, insulin).

2. Diarrhea

            ●    Can be severe; manage with antidiarrheals (e.g., loperamide) and hydration.

            ●    Interrupt treatment if Grade 3+ diarrhea occurs.

3. Skin Reactions

            ●    Rash, dry skin, or nail changes may occur.

            ●    Use moisturizers and sunscreen; avoid harsh skincare products.

4. Liver Toxicity

            ●    Monitor LFTs (ALT/AST) before and during treatment.

5. Drug Interactions

            ●    Avoid strong CYP3A inhibitors (e.g., ketoconazole, clarithromycin)—may increase toxicity.

            ●    Avoid strong CYP3A inducers (e.g., rifampin, carbamazepine)—may reduce effectiveness.

Common Side Effects

            ●    Diarrhea, nausea, vomiting

            ●    Fatigue, headache

            ●    Hyperglycemia, decreased  appetite

            ●    Rash, dry skin, nail disorders

Storage

Store at room temperature (20–25°C) in original packaging, away from moisture.

Note: Genetic testing (PIK3CA/AKT1/PTEN alterations) is required before use.