Study data support higher-dose lenvatinib for radioactive iodine-refractory thyroid cancer
An 18 mg starting dose of the oral tyrosine kinase inhibitor lenvatinib did not meet the noninferiority requirement compared with the approved, 24 mg starting dose for adults with radioactive iodine-refractory thyroid cancer, data show.
Topline results from study 211, a phase 2 trial evaluating the efficacy and safety of two starting doses of lenvatinib (Lenvima, Eisai) showed that the lower, 18 mg starting dose was not noninferior to the approved, 24 mg starting dose in adults with radioactive iodine-refractory differentiated thyroid cancer (DTC) as measured by objective response rate (ORR) at week 24. The data from this study support the selection of 24 mg as an appropriate starting dose, Eisai said in a press release.
Study 211 was conducted as a post-marketing commitment to the FDA, the European Medicines Agency and other regions following priority review designation and approval of lenvatinib for adults with locally recurrent or metastatic, progressive, radioactive iodine-refractory DTC.
"These findings help reinforce the efficacy and safety of Lenvima for patients living with RAI-refractory differentiated thyroid cancer while supporting the appropriate starting dose for these patients," Takashi Owa, MD, chief medicine creation and chief discovery officer, Oncology Business Group at Eisai, said in the release. "Studies like this post-marketing trial represent Eisai's continued commitment to prioritizing patients' needs and safety through the ongoing examination of our medicines.”
The primary objective of the randomized, double-blind study was to determine whether an 18 mg starting dose of lenvatinib once daily would provide comparable efficacy based on ORR at 24 weeks with an improved safety profile compared with the 24 mg starting dose, based on treatment-emergent adverse events of grade 3 or higher. The 18 mg dose did not show noninferiority in efficacy to the 24 mg dose as measured by ORR at week 24. The primary safety endpoint demonstrated that the incidences of grade 3 or higher treatment-emergent adverse events through week 24 were similar between dose arms.
With an estimated incidence of four cases per million population year, thyroid cancer that does not respond to radioactive iodine therapy is rare. As Healio previously reported, for most of those patients, the prognosis is poor, with a 10-year survival rate of 10% from the time metastatic lesions are detected. In 2020, it is estimated that there will be 52,890 new cases of thyroid cancer in the U.S. and that women are three times more likely to develop thyroid cancer as men.
Eisai said the full results of the study will be presented at an upcoming medical conference.
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