Clinical course of tarlatamab as third-line therapy for small-cell lung cancer on haemodialysis: a case report

Tarlatamab, a DLL3-directed, CD3-engaging bispecific T-cell engager, has demonstrated efficacy in extensive-stage small cell lung cancer (ES-SCLC) after platinum-based chemotherapy; however, evidence for its efficacy in patients with renal dysfunction requiring dialysis remains scarce. We describe the case of a 76-year-old man with chronic kidney disease on maintenance haemodialysis and ES-SCLC (cT4N3M1c with malignant pleural effusion and adrenal and brain metastases; stage IVB) receiving four carboplatin/etoposide/atezolizumab cycles, followed by 11 amrubicin cycles. During treatment, whole-brain radiotherapy (30 Gy/10 fractions) and stereotactic radiotherapy to the right frontal brain metastasis (35 Gy/10 fractions) were performed. Upon subsequent mediastinal and right adrenal progression, third-line tarlatamab treatment was initiated. On day 12 after treatment initiation, immune effector cell–associated neurotoxicity syndrome grade 3 was diagnosed, and dexamethasone treatment was started. The patient’s course was complicated by aspiration pneumonia with acute respiratory failure. Follow-up computed tomography demonstrated 31% reduction in the target lesions. However, treatment was discontinued because of performance status decline, and he was transitioned to best supportive care. The survival time was approximately 17.5 months from the initial diagnosis of SCLC and 2.3 months from the initiation of tarlatamab therapy. Although radiologic evaluation demonstrated shrinkage of the target lesions, continuation of tarlatamab was not feasible in this case because of performance status deterioration associated with ICANS and pneumonia. Given the limited evidence regarding the safety of tarlatamab in dialysis patients, its use in this population requires careful consideration and close monitoring.