Cabozantinib As Salvage Therapy for Patients With Tyrosine Kinase Inhibitor–Refractory Differentiated Thyroid Cancer: Results of a Multicenter Phase II International Thyroid Oncology Group Trial
Mené sur 25 patients atteints d'un cancer différencié de la thyroïde réfractaire à l'iode radioactif (âge médian : 64 ans), cet essai de phase II évalue l'efficacité, du point de vue du taux de réponse objective, et la toxicité du cabozantinib en traitement de sauvetage après l'échec d'une thérapie ciblée anti-VEGF
Purpose : Sorafenib and lenvatinib are oral multikinase inhibitors targeting vascular endothelial growth factor receptor (VEGFR) and approved for radioiodine (RAI)-refractory differentiated thyroid cancer (DTC). However, there are no approved second- or third-line therapies. MET is implicated in resistance to VEGFR inhibitors. Cabozantinib is an oral multikinase inhibitor targeting MET in addition to VEGFR and is approved for medullary thyroid cancer. In a phase I study of cabozantinib, five of eight patients with DTC previously treated with a VEGFR-targeted therapy had an objective response to cabozantinib. Patients and Methods : Patients with RAI-refractory disease with Response Evaluation Criteria in Solid Tumor (RECIST) measurable disease and evidence of progression on prior VEGFR-targeted therapy were enrolled in this single-arm phase II study. The cabozantinib starting dose was 60 mg/day orally but could be escalated to 80 mg if the patient did not experience a response. Patients underwent tumor assessment according to RECIST v1.1 every 8 weeks. In this study, if at least five of 25 response-evaluable patients had an objective response, cabozantinib would be considered a promising agent in this patient population. Results : Twenty-five patients were enrolled. The median age was 64 years, and 64% of patients were men. Twenty-one patients had received only one prior VEGFR-targeted therapy (sorafenib, pazopanib, or cediranib), and four patients had received two such therapies. The most common treatment-related adverse events were fatigue, weight loss, diarrhea, palmar-plantar erythrodysesthesia, and hypertension. One drug-related death was noted. Of the 25 patients, 10 (40%) had a partial response, 13 (52%) had stable disease, and two (8%) had nonevaluable disease. The median progression-free survival and overall survival were 12.7 months and 34.7 months, respectively. Conclusion : Cabozantinib demonstrated clinically significant, durable objective response activity in patients with RAI-refractory DTC who experienced disease progression while taking prior VEGFR-targeted therapy.