Abstract
Purpose :
MEK inhibitors have been reported to cause retinopathy characterized by subretinal fluid (SRF) accumulation. Understanding the clinical characteristics of this retinopathy helps assess the risks and benefits of treatment, and may shed light on its etiology. Our data characterizes the retinopathy associated with the MEK inhibitor binimetinib, and correlates the symptoms, signs, and resolution to the time course of treatment.
Methods :
Retrospective cohort study of clinical trial participants on binimetinib reviewed at the Royal Melbourne Hospital between November 2011 and October 2013.
Results :
22 eyes of 11 subjects were included. The mean subject age was 60.8 years. 20/22 eyes developed SRF at a mean of 14.9 days after commencement of binimetinib, with 10% of eyes being symptomatic. In those whose dose of binimetinib was immediately reduced (8 eyes), resolution of the SRF occurred at a mean of 7.1 days. In those whose original dose of binimetinib was maintained (6 eyes), the SRF resolved at a mean of 21.0 days. Six eyes were lost to follow up. Of those that developed SRF, half were subfoveal and half were extrafoveal. The mean number of fluid foci per eye was 6.7 ± 4.8. All foci were less than 2-disc diameters in size, appearing as yellow-gray globules on color fundus photography. Near-infrared reflectance images showed lesions with a hyperreflective center surrounded by hyporeflective ring. On optical coherence tomography, the SRF was located between the interdigitation zone (IZ) and the retinal pigment epithelium. There was no statistically-significant difference in LogMAR best corrected visual acuity when comparing baseline vision to the vision while SRF was present (p = 0.72), or when comparing baseline vision to the vision after SRF resolution (p = 0.54). On average, the IZ thickness was 50% greater than baseline while SRF was present (p < 0.01) and normalized after SRF resolution.
Conclusions :
The presence of SRF is common in patients undergoing treatment with binimetinib, but is usually asymptomatic. SRF resolution occurred in our cohort regardless of whether the dose of binimetinib was reduced, and in all cases central visual acuity was preserved. Cessation or reduction of binimetinib is not indicated when SRF is present. Binimetinib retinopathy is characterized by IZ thickening, a feature that may inform future studies on its etiology.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.