A case of panuveitis and retinal vasculitis associated with pembrolizumab therapy for metastatic lung cancer

PURPOSE: To report a case of panuveitis and retinal vasculitis associated with pembrolizumab therapy for metastatic lung cancer. OBSERVATIONS: A 71-year-old man, who was diagnosed with metastatic lung cancer (squamous cell carcinoma), presented with blurry vision 2 weeks after the initiation of pembrolizumab monotherapy. His best-corrected visual acuity (BCVA) was 20/20 OU, and slitlamp examination revealed fine keratic precipitates, anterior chamber cells (1+) and flare (1+) in both eyes. Dilated fundus examination showed no remarkable finding in the right eye and vitreous haze (2+), perivascular exudates, and vessel sheathing in the left eye. Fluorescence angiography demonstrated dye leakage from the optic disc and both retinal arteries and veins extending from the posterior to the peripheral retina in both eyes. The patient was diagnosed with panuveitis and retinal vasculitis as Grade 3 immune-related adverse event (irAE). Pembrolizumab was discontinued and oral prednisone 70mg/day was given for 1 week. The dose was reduced to 30mg/day for the next 3 weeks and was then stopped. One month after the treatment, intraocular inflammation became quiescent. With a good response to the treatment of irAE, pembrolizumab was restarted. Recurrence of ocular inflammation occurred over the next 1.5 years, but all of which were successfully treated with sub-Tenon's injection of triamcinolone acetonide (STTA). The patient maintained BCVA of 30/20 OU at the latest visit. CONCLUSIONS AND IMPORTANCE: We showed a case of retinal vasculitis occurred as an irAE of pembrolizumab for metastatic lung cancer. Retinal vasculitis was well managed with transient pembrolizumab discontinuation and oral corticosteroid therapy, and pembrolizumab was restarted with the aid of STTA. As ocular irAEs might be controlled by local corticosteroid therapy, the decision to continue immune checkpoint inhibitor therapy should be made on a case-by-case basis.