Intralesional rituximab injections for orbital granulomatosis with polyangiitis: a case series and literature review

Rituximab, an anti-CD-20 monoclonal antibody, has garnered increasing interest as a therapeutic option in orbital inflammatory disease (OID). We report our institutional experience with intralesional rituximab injections in two cases of orbital granulomatosis with polyangiitis (GPA), and additionally review the literature surrounding intralesional rituximab in OID. Two patients (a 74-year-old male (Case 1) and a 63-year-old female (Case 2)) with orbital GPA received intralesional rituximab injections at our tertiary institution. Case 1 had evidence of left optic neuropathy in extensive bilateral inferomedial orbital inflammation, while Case 2 had severe refractory and relapsing left orbital inflammation. Both patients received intralesional rituximab injections (Riximyo 10 mg/ml), administered weekly over 8-11 weeks. Rituximab injections were adjunctive to systemic induction therapy, including corticosteroids and rituximab infusion in Case 1, and a course of corticosteroids only in Case 2. Both patients demonstrated a clinico-radiological response to treatment. In conclusion, we present our experience with intralesional rituximab injections, used as an adjunctive treatment modality for orbital GPA, in a case of optic neuropathy and another of severe, refractory, and relapsing disease. Further prospective studies are required to define its utility and the long-term outcomes of intralesional rituximab injections in OID.