A 77-year-old male patient was referred to our hospital with frailty, accompanied with muscle weakness and gait disturbance, and bilateral lower leg resting pain. Blood tests showed severe thrombocytopenia without remarkable coagulopathy, and cranial CT revealed multiple focal hemorrhages (Fig. 1a), which suggested a potential cause for the gait disturbance. At the onset of intracranial hemorrhage, the patient’s platelet count was 0.3 × 104/μL. Diagnostic testing for thrombocytopenia was performed by examining bone marrow aspirate. We diagnosed idiopathic thrombocytopenic purpura (ITP) based on the unrepressed proliferation of megakaryocytes in the hyperplastic bone marrow (day 0). His presentation was not consistent with any other possible differential diagnosis. We did not observe any immunological abnormalities in the blood tests, including anti-cardiolipin antibody and lupus anticoagulant (anti-CL–β2GP1 complex). Soon after the diagnosis of ITP, the patient was treated with prednisolone at 1.0 mg/kg/day. His platelet count immediately recovered from 0.2 × 104 to 13.8 × 104/μL 10 days after corticosteroid treatment. Seventeen days after prednisolone treatment for ITP, the pain in the patient’s right leg was exacerbated, and ischemia and cyanosis were observed (day 17). CT angiography revealed arterial sclerosis obliterans in the right leg (Fig. 1b), with a platelet count of 17.0 × 104/μL and rhabdomyolysis, showing creatinine kinase elevation to 6798 U/L (normal range 40–200 U/L). After recovery of the platelet count, he underwent catheter intervention that restored the blood flow (day 83) (Fig. 1c).
Antibody–drug conjugates (ADCs) are novel agents that have shown promise across multiple tumor types. Explore the current landscape of ADCs in breast and lung cancer with our experts, and gain insights into the mechanism of action, key clinical trials data, existing challenges, and future directions.