Analysis of the Reasons for Dose Reduction or Discontinuation of Sunitinib in Korean Patients

Sunitinib, an oral multi-targeted kinase inhibitor, is used as a primary treatment agent in patients with metastatic or recurrent renal cell carcinoma. High incidence of sunitinib adverse drug reactions was reported in Asian patients. The objective of this study was to identify and characterize the reason for dose reduction or discontinuation of the sunitinib treatment. We, retrospectively, collected the data from patients who received sunitinib from March 2007 to August 2011. A total of 171 patients were included in this study. Among them, 77 patients (45.0%) required dosage reduction of sunitinib. 59 patients (34.5%) discontinued sunitinib immediately without dosage reduction. Of all patients who required dosage reduction, 37 patients (48.1%) continued with sunitinib. Dosage reduction or discontinuation due to adverse effects was observed in 96 of 171 patients (56.1%). The type of adverse effects, which required dosage modification, was as follows : intolerance (30.2%), hematologic toxicity (13.5%), dermatologic toxicity (11.5%), gas-trointestinal toxicity (11.5%), hypertension (8.3%), bleeding (7.0%) and others. Dosage reduction or discontinuation due to adverse events was significantly more common in patients who were female, old and known to have brain metastasis. In conclusion, this study confirmed that the incidence of dose reduction or discontinuation of sunitinib due to adverse events is high in Korean patients. The main type of adverse effect that required dosage modification is intolerance, hematologic toxicity, and skin toxicity. Women, old age and patients with brain metastasis are more susceptible to sunitinib adverse effect. This information might be helpful for pharmacists to counsel patients receiving sunitinib and to improve their medication adherence