Posterior segment inflammation with venous involvement following a switch to a ranibizumab biosimilar (Ximluci®): a case report

Purpose To describe an unusual case of posterior segment inflammation occurring in temporal association with a switch from reference ranibizumab to its biosimilar, Ximluci®. Observations A 77-year-old woman with neovascular age-related macular degeneration presented for an unscheduled visit reporting mild subjective visual loss one day after the second monthly intravitreal injection of ranibizumab biosimilar Ximluci following ten consecutive monthly injections of reference ranibizumab without adverse events. Clinical examination revealed mild optic disc edema, and peripapillary venous leakage on fluorescein angiography, without arteriovenous filling delay or ischemic signs. Multimodal imaging findings were consistent with posterior segment inflammation with venous involvement. Infectious and systemic inflammatory work-up was negative. The patient was treated with systemic and topical corticosteroids, resulting in progressive resolution of inflammatory signs. Due to suboptimal anatomical response of the underlying neovascular lesion and the recent inflammatory episode, therapy was subsequently switched to 2 mg Aflibercept, which was well tolerated without recurrence of intraocular inflammation. Conclusion and importance This case highlights a rare episode of posterior segment inflammation occurring in temporal association with a switch to a ranibizumab biosimilar. Although ranibizumab biosimilars have demonstrated a favorable safety profile in clinical trials and regulatory assessments, uncommon inflammatory reactions may emerge in real-world settings. Careful clinical monitoring following treatment switching and continued post-marketing surveillance are essential to further characterize the ocular safety of these agents.