Ocular Changes in Metastatic Melanoma Patients Treated with MEK Inhibitor Cobimetinib and BRAF Inhibitor Vemurafenib

Background

Mitogen-activated protein kinase kinase (MEK) inhibitor cobimetinib and V-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitor vemurafenib have significantly improved the prognosis of BRAF-mutated metastatic melanoma. Some ocular symptoms and signs were recently recognized to follow this treatment. The study was aimed to investigate ocular toxicity in patients with metastatic melanoma treated with cobimetinib in combination with vemurafenib.

Patients and methods

In the prospective, observational study, patients with BRAF-mutated metastatic melanoma treated with cobimetinib in combination with vemurafenib at the Institute of Oncology Ljubljana were asked to participate. Ophthalmic examination was performed including measurement of visual acuity and intraocular pressure, slit lamp examination, funduscopy (CF), infrared-reflectance (IR) imaging and optical coherence tomography (OCT).

Results

Five out of 7 patients noticed changes in vision few days after starting the therapy with cobimetinib. In all patients, small circular lesions, described as MEKAR lesions, were documented in outer retinal layers demonstrated with OCT, IR, and CF. Changes were in the center and/or scattered over the retina almost symmetrical in both eyes in 6 patients, and asymmetrical in one patient, the latter presented also with unilateral anterior uveitis and cystoid macular edema.

Conclusions

Multiple bilateral foveal and extrafoveal small retinal lesions in the outer retinal layers develop in patients treated with MEK inhibitor in combination with BRAF inhibitor. Ophthalmologists and oncologists need to be aware of this common, yet relatively benign and often transient ocular side effect to avoid needless intervention, including the discontinuance of a potentially life-prolonging therapy.

Ocular toxicities associated with targeted anticancer agents: an analysis of clinical data with management suggestions

Ocular toxicities are among the most common adverse events resulting from targeted anticancer agents and are becoming increasingly relevant in the management of patients on these agents. The purpose of this study is to provide a framework for management of these challenging toxicities based on objective data from FDA labels and from analysis of the literature. All oncologic drugs approved by the FDA up to March 14, 2015, were screened for inclusion. A total of 16 drugs (12 small-molecule drugs and 4 monoclonal antibodies) were analyzed for ocular toxicity profiles based on evidence of ocular toxicity. Trials cited by FDA labels were retrieved, and a combination search in Medline, Google Scholar, the Cochrane database, and the NIH Clinical Trials Database was conducted. The majority of ocular toxicities reported were low severity, and the most common were conjunctivitis and "visual disturbances." However, severe events including incidents of blindness, retinal vascular occlusion, and corneal ulceration occurred. The frequency and severity at which ocular toxicities occur merits a more multidisciplinary approach to managing patients with agents that are known to cause ocular issues. We suggest a standardized methodology for referral and surveillance of patients who are potentially at risk of severe ocular toxicity.