Marcia S. Brose, MD, Ph.D. of the Pearlman School of Medicine at The University of Pennsylvania discusses the ESMO 2020 abstract Final analysis of RIFTOS MKI, a global, non-interventional study assessing the use of multikinase inhibitors (MKIs) for the treatment of patients with asymptomatic radioactive iodine-refractory differentiated thyroid cancer (RAI-R DTC).
Abstract 1918P
Background
In patients with RAI-R DTC, MKIs effectively extend progression-free survival but are associated with notable toxicity. There is currently no consensus about when systemic therapy should be initiated by patients with asymptomatic RAI-R DTC.
Methodology
A global non-interventional research, enrolling patients with asymptomatic RAI-R DTC, RIFTOS MKI is designed to assess the results of patients treated at the start of the study with/without MKIs. From the final review, we report baseline characteristics and protection here; results of effectiveness are pending.
Outcomes
Of the 656 patients enrolled and valid for study, 45% were male, with a median age of 67 years and a median weight of 75 kg, with a median observation period of 27.7 months. Most patients had a performance rating of 0 or 1 in the Eastern Cooperative Oncology Community at study entry (95 percent), papillary histology was the most normal (74 percent), and 91 percent of patients had metastatic disease. The median time from initial DTC diagnosis to study entry was 6.7 years, and the lack of RAI adoption (64 percent) was mainly due to RAI refractoriness. The median mean dose and median cumulative dose were 127.8 mCi (4.73 GBq) and 250.0 mCi (9.25 GBq) respectively for prior RAI treatment. Overall, 205 patients (31 percent) received sorafenib, and 217 patients (33 percent) received another MKI, including lenvatinib (30 percent), at any time during the study. The median period of exposure to sorafenib was 13.1 months, and the initial dosage was 800 mg/day for the majority of patients. Of the 205 patients included in the safety review of sorafenib, 181 (88%) had about 1 adverse event (AE) and 68 (33%) had about 1 extreme AE; 86 patients (42%) reported hand-foot skin reaction (HFSR) and 18 patients (9%) reported grade 3 HFSR.
Findings
For patients with asymptomatic RAI-R DTC in real-life conditions, the final review of RIFTOS MKI offers baseline characteristics and clinical practices. Safety evidence from patients treated with sorafenib is consistent with the known safety profile of sorafenib. Of note, in real-life practice, HFSR seems to be documented less frequently than in phase III clinical trials.
Identification of Clinical Trial
About NCT02303444.