Interim baseline characteristics from RIFTOS MKI, a global non-interventional study assessing the use of multikinase inhibitors (MKIs) in the treatment of patients with asymptomatic radioactive iodine-refractory differentiated thyroid cancer (RAI-R DTC).

Abstract

6084 Background: RIFTOS MKI was designed to compare the time to symptomatic progression from study entry in patients with RAI-R DTC for whom there was a decision to treat or not to treat with an MKI in the real-life setting. Here, we report interim baseline characteristics for the first 274 patients enrolled in the study. Methods: RIFTOS MKI is a non-interventional study enrolling patients with asymptomatic RAI-R DTC. The decision to initiate MKIs at study entry was at the discretion of the treating physician. Final analysis will be performed once 700 patients have been enrolled and the last enrolled patient has been followed for 24 months. Results: Of 274 patients, the median duration of observation was 169.5 days. Patients have been enrolled from USA (n = 74), Japan (n = 55), Europe (n = 80), and rest of the world (n = 65); 54% were female and the median age was 68 years. Most patients had an ECOG performance status of 0 or 1 (97%) and distant metastases (81%). The most frequent histology was papillary (73%). The median time from initial diagnosis of DTC to study entry was 7 years. RAI refractoriness was mainly due to lack of RAI uptake (60%), primarily in Japan (80%). Japan also had the shortest median time from RAI classification to initial visit (2 months) vs other regions, and the average dose per RAI treatment and median cumulative activity of RAI were lower in Japanese patients (3.4 and 3.7 GBq, respectively) (Table). Conclusions: The RIFTOS MKI study is the largest non-interventional study in RAI-R DTC. The regional differences in treatment history observed in the RIFTOS MKI study reflect differences in accessibility and treatment practice. The study is ongoing. Clinical trial information: NCT02303444. [Table: see text]