Imatib 400mg Tablet (Imatinib mesylate)

Imatib 400mg Tablet contains imatinib 400 mg, an oral tyrosine kinase inhibitor that blocks BCR::ABL1, KIT, and PDGFR kinases. It transformed chronic myeloid leukemia (CML) by directly targeting the BCR::ABL1 fusion oncoprotein generated by the Philadelphia chromosome.

Imatinib 400mg Tablet is also used in gastrointestinal stromal tumors (GIST) driven by KIT/PDGFRA and several rarer kinase-driven diseases. The Imatinib 400 mg tablet is commonly used for adult dose strength, but exact dosing varies by disease phase, mutation profile, age, and treatment response.

Major indications include newly diagnosed Philadelphia-chromosome-positive CML in the chronic phase and other CML phases; Ph-positive ALL in appropriate combinations; unresectable/metastatic KIT-positive GIST and adjuvant GIST after resection in selected high-risk patients; and certain PDGFR-rearranged myelodysplastic/myeloproliferative disorders, hypereosinophilic syndrome, aggressive systemic mastocytosis, and dermatofibrosarcoma protuberans when the relevant molecular features are present. In GIST, PDGFRA D842V mutations are resistant to imatinib 400 mg tablet and require other treatment.

Imatinib 400mg tablets bind the ATP-binding site of BCR::ABL1, KIT, and PDGFR kinases and lock them in an inactive conformation, shutting down proliferative signalling.

IRIS trial: The imatinib 400 mg tablet produced dramatically better cytogenetic and long-term outcomes than interferon-based therapy in newly diagnosed chronic-phase CML.

GIST trials: Imatinib 400 mg tablets produced durable disease control in advanced KIT-positive GIST and improved recurrence-free survival as adjuvant therapy in high-risk resected GIST.

Just like any other medication, the Imatib 400mg Tablet is also associated with some side effects. Most of the side effects are minor and usually go away within some time. Here are some of the symptoms, including:

Common side effects

• Fluid retention/edema
  
• Nausea
  
• Diarrhea
  
• Muscle cramps
  
• Rash
  
• Fatigue
  
• Low blood counts
  

Serious side effects

• Severe fluid retention/heart failure
  
• Hepatotoxicity
  
• Severe cytopenias
  
• Tumor lysis syndrome
  
• GI bleeding/perforation in GIST
  
• Growth retardation in children
  

Important: Dose and regimen must be prescribed by the treating specialist. Tablet/vial strength is not necessarily the patient dose. Do not start, stop, split, combine, or substitute treatment based on website information.

Take a missed dose when remembered unless close to the next dose; do not double. If vomiting occurs, do not automatically repeat the dose.

• CBC
  
• Liver function
  
• BCR::ABL1 transcript levels in CML
  
• Mutation testing if treatment failure occurs
  
• Weight/edema
  
• Disease-specific imaging in GIST
  

• Current imatinib 400 mg tablet prescribing information (Gleevec/reference). https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/021588s047lbl.pdf​
  
• O’Brien SG, et al. IRIS. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa1609324
  
• Demetri GD, et al. Imatinib in advanced GIST. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa020461
  
• Current ELN/NCCN CML and GIST guidelines. https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1427​
  
• Nature. Blood camcer journal. https://www.nature.com/articles/s41408-026-01485-z​