OBJECTIVES:This study aims in the identification of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) associated with vemurafenib using disproportionality analysis of the FDA database of Adverse Event Reporting System (FAERS).

METHODS:Data were obtained from the public release of data in FAERS. Case/non-case method was adopted for the analysis of association between vemurafenib use and DRESS. The data mining algorithm used for the analysis was Reporting Odds Ratio (ROR) and Proportional Reporting Ratio (PRR). A value of ROR-1.96SE>1, PRR≥2 were considered as positive signal.

RESULTS:A total of 7,869 reports for DRESS have been reported in the FDA database. Amongst which 101 reports were associated with vemurafenib. DRESS ranked 49^th among 900 vemurafenib associated adverse drug events. The mean age was 55.87 (95% CI, 52.21- 59.52) and female to male ratio was 1.466:1. A positive signal was obtained with ROR: 13.10 and PRR: 13.12. Four deaths were reported and the non-death serious reports included hospitalization, life-threatening, disability, and other serious events with 61, 11, 2 and 39 reports respectively. Linear regression analysis indicated there was a significant correlation between the PRR and time (R=0.810; p=0.027) and ROR and time (R=0.807; p=0.028). The Log Likelihood ratio for DRESS with vemurafenib was found to be 151.14 and the reporting ratio was 11.11 (Critical value-5.59).

CONCLUSIONS:A positive signal was observed for vemurafenib associated DRESS, although a causal relation cannot be definitively proved. Health care professionals should be cautious about the possibility of encountering serious adverse events associated with vemurafenib and should be reported to the regulatory authorities.