Intralesional Rituximab: A New Therapeutic Approach for Patients with Conjunctival Lymphomas

Abstract

The tolerability and activity of the intralesional administration of rituximab, a chimeric monoclonal antibody that targets the CD20 antigen, was assessed in patients with conjunctival B-cell lymphoma. The systemic administration of rituximab has varying response rates with different types of lymphoma, generally with a mild toxicity level. Intralesional administration of this drug has increased local disease control in cases of cutaneous mucosa-associated lymphoid tissue (MALT) lymphoma. This was an interventional pilot study of 3 patients with relapsed CD20+ conjunctival lymphomas treated with intralesional injections of rituximab. Two patients with conjunctival MALT lymphoma refractory to previous systemic treatment with rituximab and 1 patient with relapsed follicular lymphoma of the eyelid were included in the study. Patients received 4 weekly intralesional injections followed by 6 monthly injections of undiluted rituximab together with xylocaine 2%. Side effects and tumor response were assessed before each intralesional injection and at 3-month intervals after treatment conclusion. The 2 conjunctival MALT lymphoma patients achieved complete remission after intraconjunctival rituximab treatment, which shows that this method of administration can overcome the primary resistance to this monoclonal antibody. The patient with the eyelid follicular lymphoma did not achieve tumor regression after the first intralesional injections of rituximab. In this patient, the addition of autologous serum resulted in lymphoma remission at the end of treatment, suggesting that drug inefficacy can be related to the low bioavailability of effectors in the tumor tissue. Although follow-up is still short, these preliminary findings suggest that intralesional rituximab is a well-tolerated strategy in marginal-zone and follicular lymphomas of the conjunctiva. An increased bioavailability of effectors in the tumor tissue, by means of the addition of autologous serum, may improve rituximab activity. This strategy could be used in other extranodal CD20+ indolent lymphomas to improve local control, even in patients who are initially refractory to systemic rituximab treatment.