LuciAvap Avapritinib Tablets

Avapritinib: Detailed Product Information

I. Basic Information

Generic Name: Avapritinib

Brand Name: Taijihua (Mainland China), Ayvakit (Global)

Specification: 100 mg × 30 tablets per box

Manufacturer: Lucius Pharmaceutical (Laos) Co., Ltd.

II. Indications and Limitations

1. Indications:

Gastrointestinal Stromal Tumor (GIST) with *PDGFRA* Exon 18 Mutation:

Unresectable or metastatic adult patients, including those with the *PDGFRA* D842V mutation.

Indolent Systemic Mastocytosis (ISM):

Approved by the US FDA (June 2023); not yet approved in China.

2. Limitations of Use:

Contraindications: Pregnant women, breastfeeding women, and patients with severe hepatic or renal impairment.

III. Mechanism of Action

Target: Selectively inhibits KIT and *PDGFRA* tyrosine kinases, thereby blocking signal transduction mediated by mutated kinases and inhibiting tumor proliferation.

Unique Advantage: The only highly effective inhibitor specifically targeting the *PDGFRA* D842V mutation; effective against drug-resistant mutations.

IV. Dosage and Administration

1. Recommended Dosage:

GIST: 300 mg orally once daily, taken on an empty stomach (at least 1 hour before or 2 hours after a meal).

Dosage Adjustment:

Concomitant use with moderate CYP3A inhibitors: Reduce dose to 100 mg once daily.

Management of Adverse Reactions: Stepwise dose reduction (200 mg → 100 mg → Discontinuation).

2. Management of Missed Doses and Vomiting:

If a dose is missed, it may be taken within 8 hours of the scheduled time; otherwise, skip the missed dose. If vomiting occurs after taking the medication, do not take an additional dose.

V. Adverse Reactions

1. Common Adverse Reactions (≥20%):

Gastrointestinal System: Nausea (45%), Diarrhea (26%), Vomiting (24%).

Systemic Symptoms: Fatigue (40%), Edema (33% periorbital edema; 23% peripheral edema), Anemia (39%). 2. Serious Risks:

Intracranial hemorrhage (requiring permanent discontinuation), liver injury (elevated ALT/AST), rhabdomyolysis (myalgia, elevated CPK). 

Dose-related toxicity: 48.7% of patients required dose reduction; 9.6% permanently discontinued treatment.

VI. Precautions and Contraindications

1. Monitoring Requirements:

At baseline and during treatment: Liver function, complete blood count (CBC), and CPK levels; assess for tumor progression every 3 months.

2. Special Populations:

Pregnant Women: Animal studies have demonstrated embryotoxicity; strict contraception is required. 

Hepatic/Renal Impairment: No dose adjustment is required for mild to moderate impairment; use with caution in cases of severe impairment.

3. Drug Interactions:

CYP3A Inhibitors/Inducers: Avoid concomitant use with strong or moderate inhibitors/inducers; adjust dosage if necessary.

VII. Pharmacokinetics

Half-life: Approximately 70 hours; the active metabolite, GFT1007, has a half-life of 15 hours.

Excretion Route: 77% excreted via feces; 19% excreted via urine.

VIII. Storage and Packaging

Storage Conditions: 15–30°C; protect from light and moisture; keep sealed in the original container.

Note: The information above is compiled from clinical trials and the product prescribing information. Specific medication use should strictly follow a physician's instructions. In the event of severe adverse reactions, discontinue the medication immediately and seek medical attention.