Alectinib-Induced Pleural and Pericardial Effusions in ALK-Positive NSCLC.

Alectinib is the first-line targeted treatment for advanced ALK-positive non-small-cell lung cancer. Although it has a relatively mild toxicity profile, adverse events (AEs) do occur. We present a case of alectinib-induced bilateral pleural effusions and pericardial effusion that has not previously been reported. The patient developed severe dyspnea 3 months after starting alectinib. He underwent thorough clinical examination including evaluations of heart function. The heart function was normal. There was no sign of pneumonitis or progressive disease on the CT scans. Cytology samples of the pleural fluid from multiple thoracocenteses were examined and showed no malignant cells. Next-generation sequencing (NGS) analysis of circulating tumor DNA from sequential blood samples was also carried out. NGS identified no known driver mutations associated with the effusions. Hence, the effusions were suspected to be an alectinib-induced AE. Alectinib was withdrawn, and the patient commenced brigatinib. The effusions subsequently regressed.