Trends in Reports of Statin-Associated Immune-Mediated Necrotizing Myopathy Using the Japanese Adverse Drug Event...

Area of Science:

• Pharmacovigilance
• Clinical Pharmacology
• Drug Safety

Background:

• Package insert precautions for statin drugs were updated in October 2016 to address immune-mediated necrotizing myopathy (IMNM).
• Assessing the impact of these revised precautions on reported IMNM cases is crucial for patient safety.

Purpose of the Study:

• To evaluate the trend of statin-associated IMNM in Japan before and after the 2016 revision of drug safety precautions.
• To quantify the incidence of IMNM cases attributed to statin therapy.

Main Methods:

• Utilized the Japanese Adverse Drug Event Report and Japan Medical Data Center (JMDC) databases for case identification and incidence rate estimation.
• Identified IMNM cases using the preferred term "immune-mediated myositis" from MedDRA version 27.1.
• Analyzed case reports from April 2004 to March 2023.

Main Results:

• A total of 172 statin-associated IMNM cases were identified in 145 reports.
• Rosuvastatin was the most frequently suspected statin (34.3%), followed by pitavastatin (25.0%) and atorvastatin (22.1%).
• Reported IMNM cases rose from 3 in 2015 to a peak of 51 in 2019, with an estimated annual incidence rarely exceeding 5 per 1,000,000 patients.

Conclusions:

• An increasing trend in statin-associated IMNM cases was observed following the release of revised package insert precautions.
• The findings underscore the importance of pharmacovigilance in detecting and monitoring drug-induced adverse events.