Recurrent Macular Edema Associated With Belzutifan Therapy for Metastatic Renal Cell Carcinoma

<b>Purpose:</b> To report a case of rapidly reversible cystoid macular edema (ME) associated with belzutifan therapy. <b>Methods:</b> A single case was reviewed. <b>Results:</b> A 70-year-old man with sporadic metastatic renal cell carcinoma developed acute symptomatic cystoid macular edema (CME) within 2 weeks of initiating belzutifan therapy. The CME began to improve within 1 week after treatment cessation and resolved completely thereafter. Belzutifan was subsequently restarted at a lower dose, following which CME recurred within 2 weeks. <b>Conclusions:</b> This is the first reported instance of rapidly reversible CME associated with the use of belzutifan in a real-world clinical setting, highlighting the need for ophthalmic monitoring in patients receiving hypoxia-inducible factor-2α inhibitors.