Case Report: A case of immune checkpoint inhibitor therapy in a patient with multiple sclerosis

Abstract

Immune checkpoint inhibitors (ICIs) have rapidly shifted the landscape of treatments in malignancy with significant improvements in survival paradigm. They have been an attractive armamentarium to the oncologists given the limited immune adverse effects with potential for deeper and durable benefits that haven't been previously noticed with chemotherapy. However, they result in unique toxicities by limiting immune self-tolerance and cause immune-mediated endocrinopathies, such as hypothyroidism, pneumonitis, colitis, hepatitis, myocarditis, meningitis, hypophysitis, etc. As such, they are contraindicated in patients with autoimmune disorders or recipients of organ transplants given the risk for reactivation or flare of the underlying autoimmune disease and rejection of the donor organ in transplants, although sporadic cases have been reported with the use of immunotherapy in such patients. Malignant melanoma is a highly aggressive cancer, with only 15-20% five-year survival rate once it has spread to the lymph nodes or has distant metastasis. ICIs have changed the landscape of advanced melanoma with exponential improvements in survival, the 5-year survival rates are about 50%. Multiple sclerosis (MS) is recognized as T cell-mediated immune response causing inflammation, which causes local inflammatory plaques and demyelination. ICIs are likely to generate an immune response that causes molecular mimicry and cross-react with CNS autoantigens, in turn exacerbating pre-existing immune response and subsequent flare-ups in MS. There is little knowledge about treating such patients with immunotherapy, short of a few case reports and series; in this report, we describe another such case. We present a case of checkpoint inhibitor therapy in a patient with multiple sclerosis who underwent immune checkpoint inhibitor therapy with pembrolizumab for metastatic malignant melanoma who had a complete response to treatment at the cost of MS relapse, which was managed with high-dose steroids.