[Orbital myositis associated with ipilimumab].

BACKGROUND: Ipilimumab is a monoclonal antibody targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) that allows increased survival and, occasionally, complete remission, in the treatment of metastatic melanoma. The most frequent adverse effects are attributed to dysimmunity. We report the case of a female patient who developed orbital myositis during treatment with ipilimumab. PATIENTS AND METHODS: A woman on ipilimumab for a heel melanoma with mediastinal metastases was referred for evaluation of painful diplopia and proptosis that began three days after the fourth infusion of ipilimumab. The clinical examination disclosed a left abductiondeficit associated with conjunctival hyperaemia and palpebral oedema. Orbital MRI disclosed enlargement of the left lateral rectus, enhancing after contrast. An extensive work-up did not find any evidence for thyroid-related eye disease, as well as other orbital inflammatory processes, orbital cellulitis or orbital metastases. Treatment with high-dose oral steroids resulted in complete clinical recovery within a few days. DISCUSSION: To our knowledge, this is the first clinical report of orbital myositis as an adverse event related to anti-CTLA-4 antibody treatment. Both timing and usual profile of adverse events support the hypothesis that orbital myositis has to be attributed there to ipilimumab. Several dysimmune toxicities were observed with ipilimumab. Ophtalmic toxicity has unusually been described. Most cases were uveitis. Whether immune-related adverse events correlate with clinical response to ipilimumab treatment remains to be determined.