WOODCLIFF LAKE, NJ, USA I August 28, 2017 I Eisai Inc. announced data from a prespecified subgroup analysis, which was published in the Journal of Clinical Oncology, showing treatment with lenvatinib (marketed as Lenvima®) resulted in a statistically significant improvement in overall survival (OS) for patients older than 65 years of age with radioactive iodine-refractory differentiated thyroid cancer (RAI-R DTC) when compared with placebo (HR: 0.53; 95% CI: 0.31 – 0.91; nominal p=0.020), despite crossover of placebo patients to lenvatinib after progressive disease. Lenvatinib is a multiple receptor tyrosine kinase inhibitor (TKI) (including fibroblast growth factor receptors [FGFR] 1 – 4) approved by the U.S. FDA for locally recurrent or metastatic, progressive, RAI-R DTC.
The article, “Effect of Age on the Efficacy and Safety of Lenvatinib in Radioiodine-Refractory Differentiated Thyroid Cancer in the Phase III SELECT Trial,” reports the results of a prespecified subanalysis of younger patients (65 years of age or younger) and older patients (older than 65 years of age) in the pivotal Phase 3 SELECT study evaluating lenvatinib versus placebo in patients with progressive, radioactive iodine-refractory differentiated thyroid cancer (RAI-R DTC) that had recurred locally or had metastasized. The median age was 56 for the younger group (n=155 treated with lenvatinib; n=81 treated with placebo) and 71 for the older group (n=106 treated with lenvatinib; n=50 treated with placebo). Other baseline characteristics were generally similar among all groups, including ECOG performance status, prior VEGF-targeted therapy, histology, and presence of BRAF mutations.
“These data are important to consider because older patients are more likely to have RAI-refractory disease which is associated with a poorer prognosis,” said Marcia Brose, MD, PhD, an associate professor of otorhinolaryngology in the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, and lead author of the study. “The results are a major milestone as they show, for the first time, that a tyrosine kinase inhibitor can significantly improve overall survival in patients older than 65 with advanced, progressive, RAI-refractory differentiated thyroid cancer.”
The OS results of this subanalysis demonstrate the efficacy of lenvatinib for older patients and indicate the association between age and poorer survival outcomes is diminished by treatment with lenvatinib. Progression-free survival (PFS) and objective response rate (ORR) benefits were also maintained in patients treated with lenvatinib regardless of age group as compared with placebo. All p-values other than for the overall population are nominal. Results of safety analyses by subgroup demonstrated that toxicity with lenvatinib was manageable for most patients, including older patients, and dose modification and discontinuation of lenvatinib was more common for older patients.
Specifically, median OS was reached only in the older placebo-treated patients (18.4 months; 95% CI; 13.3 – 20.3) – survival data was not mature in the younger patient group – and younger patients who received placebo had statistically significantly longer OS than older patients who received placebo (HR: 0.48; 95% CI: 0.27 – 0.85; p=0.010), demonstrating the known effect of age on prognosis. Despite this, overall survival was not significantly different between age groups for patients who were treated with lenvatinib (HR: 0.78; 95% CI: 0.49 – 1.26; p=0.30). Additionally, older patients who received lenvatinib experienced a statistically significant improvement in OS as compared with older patients who received placebo (HR: 0.53; 95% CI: 0.31 – 0.91; p=0.020). These data further support that treatment with lenvatinib lessened the effect of age as a predictor of poorer survival. Exploratory analyses examining patient baseline characteristics and post-study interventions (including crossover and post-progression therapy) did not identify any confounding factors that could potentially explain the improvement in OS in older patients who received lenvatinib.
In addition to showing a benefit in overall survival for older patients treated with lenvatinib, this analysis showed the PFS benefit of lenvatinib versus placebo was maintained in both age groups (younger patients: median PFS 20.2 vs. 3.2 months, HR: 0.19, 95% CI: 0.13–0.27, p<0.001; older patients: 16.7 vs. 3.7 months, HR: 0.27, 95% CI: 0.17–0.43, p<0.001) and treatment with lenvatinib resulted in better ORR compared with placebo regardless of age (younger patients: odds ratio [OR]: 45.7, 95% CI: 14.8-141.0, p<0.001; older patients: OR: 16.8, 95% CI: 4.7-60.0, p<0.001).
Results for treatment exposure and safety indicated that older patients had a shorter time to first dose reduction and more patients in the older group required a dose reduction to 10 mg/day compared with younger patients. While treatment-related adverse events (AEs) were recorded for nearly all patients, the incidence of severe (grade 3 or higher) treatment-related AEs was significantly higher in older patients than in younger patients (89% and 67%, respectively) and older patients were more likely to experience AEs that required dose modifications. Percentages of patients who experienced serious treatment-emergent AEs were similar in younger (48%) and older (55%) patients in the lenvatinib arm. Fatal treatment-emergent AEs were also similar in younger and older patients (7%, with 1% reported as treatment-related; versus 9%, with 4% reported as treatment-related). The most common treatment-related AEs were the same for both older and younger patients and were hypertension (69% and 67%), diarrhea (57% and 61%), decreased appetite (58% and 45%), decreased weight (50% and 43%) and nausea (46% and 37%).
“These results provide further evidence of the efficacy of Lenvima for older patients, a critical insight as we progress toward fully understanding the role of Lenvima as a treatment option for adult patients of all ages with this aggressive form of thyroid cancer,” said Alton Kremer, MD, PhD, Chief Clinical Officer and Chief Medical Officer, Oncology Business Group at Eisai. “Eisai is committed to the ongoing study of the SELECT trial results and other clinical trials with Lenvima, and we are pleased that this important analysis has been published in the Journal of Clinical Oncology.”