Saiweijian Raltitrexed for Injection

1. Indications and Usage
Advanced Colorectal Cancer:
Treatment of adult patients with advanced colorectal cancer who are unsuitable for 5-fluorouracil (5-FU) and folinic acid combination chemotherapy.
2. Dosage and Administration
Route of Administration:
For Intravenous (IV) Infusion ONLY.
Recommended Dosage:
Standard Dose: 3 mg/m².
Frequency: Administered once every 3 weeks.
Maximum Dose: Doses greater than 3 mg/m² are not recommended due to increased risk of life-threatening or fatal toxicities.
Critical Administration Instructions:
Dilution: Dilute in 50 to 250 mL of 0.9% Sodium Chloride Injection or 5% Glucose Injection.
Infusion Time: Administer over approximately 15 minutes.
Single Agent: Must be administered as a single agent; do not mix with other drugs in the same infusion bag or line.
Light Protection: The diluted solution must be protected from light and used within 24 hours.
3. Mechanism of Action
TS Inhibition:
Raltitrexed is a novel water-soluble antifolate that enters cells via the reduced folate carrier system.
DNA Synthesis Blockade:
Inside the cell, it is rapidly metabolized into polyglutamate derivatives, which potently and selectively inhibit thymidylate synthase (TS). This blockade depletes thymidine triphosphate pools, preventing DNA synthesis and leading to cell cycle arrest and apoptosis.
4. Safety and Warnings
Severe Gastrointestinal and Hematologic Toxicity:
The most common severe adverse reactions include diarrhea, stomatitis/mucositis, neutropenia, and thrombocytopenia. These toxicities can be life-threatening.
Renal Impairment:
Raltitrexed is primarily excreted by the kidneys. It is contraindicated in patients with severe renal impairment (creatinine clearance <25 mL/min). Dose reduction is required for mild-to-moderate renal insufficiency.
Hepatic Impairment:
Use with caution in patients with mild-to-moderate hepatic impairment; it is not recommended for patients with severe hepatic impairment (e.g., decompensated cirrhosis).
5. Adverse Reactions and Clinical Research
Most Common Adverse Reactions:
Nausea, vomiting, diarrhea, anorexia, stomatitis, neutropenia, thrombocytopenia, anemia, and elevated liver enzymes (AST/ALT).
Clinical Research Highlights:
Clinical trials have demonstrated that Raltitrexed provides comparable efficacy to standard 5-FU-based regimens, with a more favorable profile regarding cumulative cumulative neurotoxicity, but with a higher incidence of acute GI and hematologic toxicity.
6. Drug Interactions
Folic Acid and Derivatives:
Concomitant use with folic acid, folinic acid (leucovorin), or multivitamins containing these components can antagonize the therapeutic effect of raltitrexed and should be avoided.
Nephrotoxic or Myelosuppressive Drugs:
Caution is required when co-administering other agents that cause bone marrow suppression or nephrotoxicity, as the effects may be additive.
7. Pharmaceutical Information
Chemical Composition:
Active Ingredient: Raltitrexed.
Appearance: White or off-white lyophilized cake or powder.
Packaging: Single-use vial (2 mg).
Storage: Store at room temperature (15-30°C). Do not freeze.