Entrectinib-D4 is the deuterium-labeled isotope of Paquinimod. Entrectinib (T3678) is an orally active inhibitor of TrkA/B/C, ROS1, and ALK, capable of crossing the blood-brain barrier and possessing central nervous system activity, with IC50 values of 1, 3, 5, 12, and 7 nM, respectively. It induces apoptosis and cell cycle arrest in cancer cells, exhibits antitumor efficacy, and mitigates bleomycin-induced pulmonary fibrosis in mice.