A postmarketing pharmacovigilance analysis of avapritinib, a medication used in the treatment of systemic mastocytosis (SM), discovered that elderly male patients were at an increased risk of experiencing serious adverse events related to treatment. The study was published in the British Journal of Clinical Pharmacology.

The study authors extracted 3120 avapritinib-related reports submitted to the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) by June 2022. To evaluate the link between the medication and adverse events, they calculated the reporting odds ratio, proportional reporting ratio, information component, and empirical Bayes geometric mean using disproportionality analysis and Bayesian analysis.

According to the study results, there were 331 distinct adverse events related to the use of avapritinib. The most common events were fatigue, nausea, and diarrhea, with no apparent differences between sexes. Moreover, 44% of the events were reported within 30 days of treatment onset.

The scientists found a small number of adverse events linked to abnormal skin texture and executive dysfunction to be strongly associated with the use of the medication.

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Subgroup analysis indicated a higher frequency of serious adverse events in elderly male patients compared with female patients. However, no significant difference was found between the hemorrhage and nonhemorrhage groups.

Analysis of fatalities due to avapritinib-associated adverse events showed significant correlations between mortality and sex, age, and time to onset.

“Our analysis showed that the number of [adverse events] has gradually increased over recent years,” Rong and colleagues wrote. “This may simply be due to the increased use of avapritinib, the fact that the clinical efficacy of this drug has gradually been recognized since its launch, and because indications have increased since June 2021.”

The medication has also been approved for the treatment of patients with unresectable gastrointestinal stromal tumors and PDGFRA exon 18 mutations.

Reference

Rong L, Xie M, Jiang M, Qiu H, Kong L. A post-marketing pharmacovigilance study of avapritinib: adverse event data mining and analysis based on the United States Food and Drug Administration Adverse Event Reporting System databaseBr J Clin Pharmacol. Published online January 26, 2023. doi:10.1111/bcp.15673