MEK Inhibitor-Associated Ocular Hypertension.

Introduction: Mitogen-activated protein kinase kinase (MEK) inhibitors are targeted anticancer agents that are prescribed to treat a broad range of cancers. Despite their strong efficacy profile, MEK inhibitors have been associated with ocular toxicities, most notably, self-limited serous detachments of the neurosensory retina. In this report, we outline 3 cases of a rarely documented toxicity, MEK inhibitor-associated ocular hypertension. Case Presentations: In the first case, a 69-year-old female with metastatic cholangiocarcinoma presented with an intraocular pressure (IOP) of 25 mm Hg right eye (OD) and 27 mm Hg left eye (OS) 2 months after starting trametinib therapy. Similarly, in the second case, a 26-year-old female with Langerhans cell histiocytosis presented with an elevated IOP of 24 mm Hg bilaterally (OU) 13 months after beginning treatment with an investigational MEK inhibitor. In the third case, a 46-year-old male with Langerhans cell histiocytosis presented with a new onset of elevated IOP of 24 mm Hg 21 days after initiating treatment with cobimetinib. All 3 patients' IOP returned to normal following dorzolamide/timolol administration and continued their cancer therapy. Discussion/Conclusion: This report presents 3 cases of elevated IOP in patients taking three distinct MEK inhibitors which would suggest that IOP-elevating effects exist across the class of MEK inhibitors. All 3 patients had a satisfactory response to topical pressure-lowering drops while continuing their life-preserving MEK inhibitor drug dose, indicating that discontinuation of therapy may not be necessary. Due to the increasing use of MEK inhibitors, it is important that ophthalmologists familiarize themselves with the broad range of potential adverse ocular effects of MEK inhibitors.