Endocrine Abstracts

Introduction: Lenvatinib is a multitarget tyrosine kinase inhibitor that has shown substantial efficacy in patients with progressive radioiodine refractory thyroid cancer (RAIRDTC) (progression free survival (PFS) 19.4 months and objective response rate 64.8%; SELECT trial) despite common adverse events (AEs).

Objective: To evaluate efficacy and toxicity of lenvatinib treatment for RAIRDTC in daily clinical practice.

Methods: Retrospective clinical record review of 12 RAIRDTC patients treated with lenvatinib from April 2015 to December 2017 in our hospital.

Results: Twelve patients were analyzed (4 females, median age 62 years (range, 47-82)). Every patient had distant metastasis (83% lung, 67% bone, 58% lymph nodes, 25% liver) and 11 out of 12 had evidence of progressive disease (PD) within 6 months prior to lenvatinib start. Only 4 patients received lenvatinib as first line treatment (range, 1^st−6^th line). Initial dose was 24 mg in 11 out of 12 patients and 10 mg in 1 patient (82 years, ECOG 3, several comorbidities). Median follow-up (duration of treatment) was 14.9 months [0.3-33.5]. Median PFS was 24.3 months (CI 14.7 - 33.8) although data are immature since only 4 patients had progressed at the time of analysis. In 2 patients lenvatinib was not stopped despite PD; both show stable disease at last follow up (6.1 and 3.1 months after first progression). 4 of the 8 patients (50%) in which evaluation of tumour response was available achieved a partial response; 4 (50%) stable disease. No complete responses were observed. All patients presented grade 3 (G3) or superior AEs. The most frequent AEs related to treatment were fatigue (100%; 16% G3), hypertension (83%; 83% G3), nausea (75%; 8% G3), weight loss (67%; 8% G3), diarrhea (50%; 0% G3), arthralgia (50%, 0% G3), mucositis (33%; 0% G3), hand-foot syndrome (25%; 0% G3) and proteinuria (17%, 0% G3). Seven (58%) and ten (83%) patients had dose reductions or interruption of lenvatinib due to AEs. Median time to dose reduction or interruption was 1.9 months. Most dose interruptions were very brief (median duration 2 days). Median dose at last follow-up was 14.9 mg/d (range 7.1 – 24 mg/d). Two deaths occurred, one considered to be drug related (bleeding during cervical abscess surgery).

Conclusion: Remarkable benefit of lenvatinib treatment for RAIRDTC is achieved in daily clinical practice. Our results, in heavily pretreated patients, are in agreement with those of the SELECT trial. AEs are frequent and require close management and dose titration.