Impact of lung metastases on overall survival in the phase 3 SELECT study of lenvatinib in patients with radioiodine-refractory differentiated thyroid cancer
Makoto Tahara, Naomi Kiyota, Ana O. Hoff, Corin Badiu, Taofeek K. Owonikoko, Corina E. Dutcus, Takuya Suzuki, Min Ren, Lori J. Wirth
Abstract
BACKGROUND: Lung metastases may worsen overall survival (OS) in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC). We investigated (post hoc) the impact of lung metastases on survival in SELECT (a phase 3 study). PATIENTS AND METHODS: 392 patients with RR-DTC were randomised 2:1 to lenvatinib 24 mg daily (n = 261) or placebo (n = 131). Placebo-treated patients could crossover to open-label lenvatinib following progression. Patients were grouped by size of baseline lung metastases. Safety/efficacy outcomes, collated by these lung-metastases subgroups, were generated. RESULTS: Lenvatinib-treated population distributions per baseline lung metastases subgroup were any lung metastases (target/nontarget lesions; n = 226), and by maximum size of target lung lesions ≥1.0 cm (n = 199), ≥1.5 cm (n = 150), ≥2.0 cm (n = 94) and <2.0 cm (n = 105). In patients with any lung metastases, no statistically significant difference in OS was observed between treatment arms (HR: 0.76; 95% CI: 0.57-1.01; P = 0.0549). Median OS for lung metastases of ≥1.0 cm was 44.7 months (lenvatinib) versus 33.1 months (placebo) (HR: 0.63; 95% CI: 0.47-0.85; P = 0.0025). OS was significantly prolonged with lenvatinib versus placebo among patients with lung metastases of ≥1.0 cm, ≥1.5 cm, ≥2.0 cm and <2.0 cm; median OS was shorter in the ≥2.0 cm subgroup (lenvatinib: 34.7 months) versus other subgroups (lenvatinib: 44.1-49.2 months). Multivariate analysis demonstrated lenvatinib significantly prolonged OS in patients with lung metastases of ≥1.0 cm after adjustment for baseline characteristics. CONCLUSIONS: Lenvatinib treatment resulted in longer OS in patients with lung metastases of ≥1.0 cm versus placebo (even with the 89% crossover rate). Early initiation of lenvatinib may improve outcomes in patients with RR-DTC and lung metastases of ≥1.0 cm. SOURCE STUDY REGISTRATION: ClinicalTrials.Gov Identifier: NCT01321554.