Sustained Response with Dose Reduced Selpercatinib in a Pediatric
Patient with Metastatic NCOA4-RET Fusion Papillary Thyroid Carcinoma
Abstract
Understanding the molecular landscape of papillary thyroid carcinoma
(PTC), the most common thyroid cancer in children, creates additional
therapeutic approaches. RET gene rearrangements are observed in
pediatric PTC and selective inhibition of RET is now possible with
specific tyrosine kinase inhibitors designed to target diverse
RET-activating mutations. We present a 13-year-old female with
radioactive iodine-refractory metastatic PTC, found to harbor a
NCOA4-RET fusion, who responded to treatment with selpercatinib
with elimination of supplemental oxygen need, marked reduction in
pulmonary nodules and mediastinal lymphadenopathy, and substantial
improvement in thyroglobulin levels. Response was maintained despite 2
dose reductions for possibly-related weight gain.