Search

Legends for all included Supplementary Figures

Heat map of cell cycle gene expression. Gene expression was normalized and compared between the primary MTC, metastasis one, and metastasis two lesions from the whole transcriptome RNA-seq data. Purple indicates lower and yellow indicates higher expression. Values to generate colors are z-scores across each genes' relative transcript levels [log2(FPKM)].

Weight-for-age and height-for-age growth curves. Male patient weights (A), heights (B) and female patient weights (C), and heights (D) were monitored during the follow up period. Patient weight-for-age and height-for-age values were compared to U.S. Center for Disease Control reference growth curves.

Doubling time of calcitonin and CEA for patient #12 was suggestive of progressive disease. Patient #12 experienced best response 434 days after starting vandetanib, with stable lesions in the thyroid bed (showed on T2-weighted MRI of the neck, A) and the mediastinum (showed on CT of the chest, B). In August 2016, the sum of longest diameter (per RECIST) of target lesions was consistent with SD (C,D) (note that not all target lesions are shown). Biomarker response in the two years prior (E) showed CEA doubling time 1.2 years (F) and calcitonin doubling time 1.67 years (G). Patient #12 was confirmed to have PD via RECIST February 2017.

Purpose: Vandetanib is well-tolerated in patients with advanced medullary thyroid carcinoma (MTC). Long-term outcomes and mechanisms of MTC progression have not been reported previously.Experimental Design: We monitored toxicities and disease status in patients taking vandetanib for hereditary, advanced MTC. Tumor samples were analyzed for molecular mechanisms of disease progression.Results: Seventeen patients [8 male, age 13 (9–17)* years] enrolled; 16 had a RET p.Met918Thr germline mutation. The duration of vandetanib therapy was 6.1 (0.1–9.7+)* years with treatment ongoing in 9 patients. Best response was partial response in 10, stable disease in 6, and progressive disease in one patient. Duration of response was 7.4 (0.6–8.7+)* and 4.9 (0.6–7.8+)* years in patients with PR and SD, respectively. Six patients died 2.0 (0.4–5.7)* years after progression. Median progression-free survival (PFS) was 6.7 years [95% confidence interval (CI): 2.3 years–undefined] and 5-year overall survival (OS) was 88.2% (95% CI: 60.6%–96.9%). Of 16 patients with a RET p.Met918Thr mutation, progression-free survival was 6.7 years (95% CI: 3.1–undefined) and 5-year overall survival was 93.8% (95% CI: 63.2%–99.1%). No patients terminated treatment because of toxicity. DNA sequencing of tissue samples (n = 11) identified an increase in copy number alterations across the genome as a potential mechanism of drug resistance [*median (range)].Conclusions: This study demonstrates that vandetanib is safe and results in sustained responses in children and adolescents with hereditary MTC. Our preliminary molecular data suggest that an increase in copy number abnormalities may be associated with tumor progression in hereditary MTC patients treated with vandetanib. Clin Cancer Res; 24(4); 753–65. ©2017 AACR.

Legends for all included Supplementary Figures

Doubling time of calcitonin and CEA during vandetanib therapy. Calcitonin and CEA slopes and doubling times were calculated from the change during the initial four months of vandetanib (A,B), from values the year before experiencing PD or the data cutoff (C,D) and in patients that experienced progressive disease (E).

Patients #2, #5, #10, #11, #13, #15, and #16 experienced durable SD or PR during the follow up period. Calcitonin and CEA are shown as percent change from baseline at the start of vandetanib therapy (left y-axis). Tumor size is the sum of longest diameter of lesions per RECISTv1.0 (right y-axis).