What labs should be checked for patients on sunitinib (Sunitinib malate)?

Laboratory Monitoring for Patients on Sunitinib

Patients on sunitinib require regular monitoring of complete blood count, liver function, thyroid function, blood pressure, and cardiac function to prevent and manage potential toxicities.

Essential Laboratory Tests

Hematologic Monitoring

• Complete blood count (CBC) with differential to monitor for neutropenia, thrombocytopenia, and anemia, which are common hematologic toxicities with sunitinib 1
• Neutropenia occurs in up to 77% of patients (with Grade 3-4 in 17%) 1
• Thrombocytopenia occurs in up to 68% of patients (with Grade 3-4 in 9%) 1

Hepatic Function Monitoring

• Liver function tests (LFTs) including ALT, AST, alkaline phosphatase, and bilirubin 1
• ALT elevations occur in up to 61% of patients (with Grade 3-4 in 4%) 1
• AST elevations occur in up to 56% of patients (with Grade 3-4 in 2%) 1

Renal Function Monitoring

• Serum creatinine to assess renal function 1
• Urinalysis to monitor for proteinuria 2
• Creatinine elevations occur in up to 70% of patients 1

Thyroid Function Monitoring

• Thyroid stimulating hormone (TSH) every 3-6 months 3
• Hypothyroidism occurs in up to 62% of patients and risk increases with duration of therapy 3

Cardiac Monitoring

• Blood pressure measurements regularly 3
• Left ventricular ejection fraction (LVEF) assessment in patients with cardiac risk factors or symptoms 3
• Hypertension occurs in up to 34% of patients (with Grade 3-4 in 13%) 1

Metabolic Parameters

• Electrolytes (sodium, potassium, calcium, phosphorus, magnesium) 1
• Blood glucose levels 1
• Amylase and lipase to monitor for pancreatic toxicity 1

Monitoring Schedule

Baseline Tests (Before Starting Therapy)

• Complete blood count with differential 1
• Comprehensive metabolic panel (liver and renal function) 1
• Thyroid function tests (TSH) 3
• Urinalysis 2
• Cardiac evaluation including blood pressure and LVEF assessment 3

During Treatment

• CBC, liver function, and renal function tests should be checked regularly (typically every 2-4 weeks during the first few cycles) 1
• TSH should be monitored every 3-6 months 3
• Blood pressure should be monitored closely, especially during the first cycle 3, 4
• LVEF assessment should be considered in patients with cardiac symptoms or risk factors 3

Special Considerations

Cardiac Toxicity Monitoring

• For patients receiving sunitinib who develop signs and symptoms of heart failure, assessment of blood pressure control is recommended 3
• Measurement of LVEF and/or cardiac biomarkers should be considered 3
• Sunitinib should be interrupted until cardiac status is fully assessed 3

Renal Toxicity Monitoring

• Close monitoring of renal function is important as sunitinib is associated with increased risk of renal dysfunction (RR: 1.36,95% CI: 1.20 to 1.54) 4
• Proteinuria should be monitored regularly through urinalysis 2

Thyroid Dysfunction

• If hypothyroidism is detected, patients should receive thyroid hormone replacement therapy 3
• The risk of hypothyroidism increases with the duration of sunitinib therapy 3

Management of Abnormal Results

• Dose interruptions or reductions may be necessary for significant laboratory abnormalities 3
• For severe neutropenia, thrombocytopenia, or hepatotoxicity, consider dose reduction or temporary discontinuation 1
• For hypertension, appropriate antihypertensive therapy should be initiated 3
• For hypothyroidism, thyroid hormone replacement therapy should be started 3

Therapeutic Drug Monitoring Considerations

• Studies suggest that therapeutic drug monitoring of sunitinib could be useful for avoiding severe toxicities 5
• Total sunitinib concentration ≥100 ng/mL has been associated with higher incidence of Grade ≥3 toxicities 5

By following this comprehensive laboratory monitoring protocol, clinicians can effectively manage the potential toxicities associated with sunitinib therapy and optimize treatment outcomes for patients.