Doxycycline Prophylaxis in Adolescent Patients Treated With MEK Inhibitors.

Mitogen-activated protein kinase inhibitors (MEKi) are used to treat various conditions, including plexiform neurofibromas, brain tumors, and cancers. Our study aimed to determine whether doxycycline prophylaxis could reduce the frequency and/or severity of acneiform eruptions and paronychia, common side effects of MEKi. Our retrospective study included data from 43 patients aged 12 to 18 years, who received MEKi treatment at the Hospital for Sick Children, Toronto, Canada, between 2010 and 2023. We found that while doxycycline prophylaxis did not significantly impact the frequency or severity of acneiform eruptions (based on CTCAE grading), it appeared to be associated with fewer MEKi discontinuations due to skin toxicities and decreased rates of paronychia.