FGFR, BRAF, MEK, ERK and Checkpoint Inhibitor Retinopathy

This 67YO male presented with 3 weeks of mild bilateral blurred vision after starting dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor) for metastatic melanoma. Vision was 20/25 OU.

Pseudocolor SLO imaging shows multifocal bilateral macular blisters with serous subretinal fluid, confirmed on OCT.

Learning Points:
Recent drugs targeting the BRAF and MAPK pathways have emerged as therapy for metastatic melanoma. These agents, which include BRAF and MEK inhibitors, are characterized by transient, bilateral, multifocal serous retinal detachments and subretinal fluid often mimicking central serous chorioretinopathy on OCT but without angiographic leakage (Bravetti et al, Acta Ophthalmologica 2024;102:e651-e656). The serous detachments usually develop within days to weeks of initiating therapy, are dose- and time-dependent, and are usually reversible upon drug discontinuation or even with continued treatment. The pathogenesis is thought to involve disruption of the retinal pigment epithelium’s pump function due to inhibition of the MAPK pathway.