Phase 1 study of galunisertib, a TGF-beta receptor I kinase inhibitor, in Japanese patients with advanced solid tumors

Inhibition of transforming growth factor-beta receptor I (TGF-beta RI)-mediated signaling pathways blocks tumor growth and metastases in nonclinical studies. Galunisertib (LY2157299), a small molecule inhibitor of TGF-beta RI serine/threonine kinase, had antitumor effects with acceptable safety/tolerability in a first-in-human dose (FHD) study conducted mainly in Caucasian patients with glioma. In this nonrandomized, open-label, dose-escalation study, we assessed safety/tolerability, pharmacokinetics (PK), and tumor response in Japanese patients. Patients with advanced and/or metastatic disease refractory were assigned sequentially to Cohort-1 (80 mg) or Cohort-2 (150 mg) of galunisertib, administered twice daily and treated using 2-week on, 2-week off treatment cycles. Dose escalation was guided by predefined PK criteria and dose-limiting toxicities (DLT). Safety assessments included treatment-emergent adverse events (TEAEs) and cardiac safety (ultrasound cardiography/Doppler imaging, electrocardiogram, chest computed tomography, and cardiotoxicity serum biomarkers). Twelve patients (Cohort-1, n = 3; Cohort-2, n = 9) were enrolled and the most common types of cancer were pancreatic (n = 5) and lung cancer (n = 3). Seven patients (Cohort-1, n = 2; Cohort-2, n = 5) experienced possibly galunisertib-related TEAEs. The most frequent related TEAEs were brain natriuretic peptide increased (n = 2), leukopenia (n = 2), and rash (n = 2). No cardiovascular toxicities or other DLTs were reported. PK profile of galunisertib was consistent with the FHD study. Maximum plasma concentration was reached within 2 h post-dose, and the mean elimination half-life was 9 h. Galunisertib had an acceptable tolerability and safety profile in Japanese patients with advanced cancers. NCT01722825.