Case Report: Severe QL1706-associated immune-related inflammatory myopathy presenting with respiratory dysfunction, bulbar weakness, ocular motility impairment, and suspected cardiac involvement.

QL1706 is a novel bifunctional antibody targeting PD-1 and CTLA-4 that has received conditional approval in China for cervical cancer. Its full immune-related adverse event profile remains incompletely defined. Here, we report a 61-year-old woman with endometrial clear cell carcinoma who developed severe immune-related inflammatory myopathy 4 weeks after the first cycle of QL1706 combined with paclitaxel and carboplatin. She presented with dyspnoea, generalised weakness, dysphagia and ocular motility impairment. Laboratory tests showed marked elevations in creatine kinase, CK-MB, lactate dehydrogenase and cardiac troponin T, and electrophysiological findings supported a predominant myopathic process. The final diagnosis was QL1706-associated severe immune-related inflammatory myopathy with respiratory and ocular involvement and clinically suspected cardiac involvement. Myocarditis, ocular myositis and myositis-myocarditis-myasthenia gravis overlap syndrome could not be definitively confirmed. The patient improved after high-dose methylprednisolone, intravenous immunoglobulin and tacrolimus. This case highlights the need for early recognition, multidisciplinary evaluation and prompt immunosuppressive treatment for severe neuromuscular immune-related adverse events during QL1706-based therapy.