Aggressive thyroid cancer: targeted therapy with sorafenib.

Sorafenib (Nexavar), is a multikinase inhibitor, which has demonstrated both antiproliferative and antiangiogenic properties in vitro and in vivo, inhibiting the activity of targets present in the tumoral cells (c-RAF [proto-oncogene serine/threonine-protein kinase], BRAF, (V600E)BRAF, c-KIT, and FMS-like tyrosine kinase 3) and in tumor vessels (c-RAF, vascular endothelial growth factor receptor [VEGFR]-2, VEGFR-3, and platelet-derived growth factor receptor ß). Sorafenib was initially approved for the treatment of hepatocellular carcinoma and advanced renal cell carcinoma. Experimental studies have demonstrated that sorafenib has both antiproliferative and antiangiogenic properties in vitro and in vivo, against thyroid cancer cells. Furthermore, several completed (or ongoing) studies have evaluated the long-term efficacy and tolerability of sorafenib in patients with papillary, follicular and medullary aggressive thyroid cancer. The results of the different studies showed good clinical responses and stabilization of the disease and suggested that sorafenib is a promising therapeutic option in patients with advanced thyroid cancer that is not responsive to traditional therapeutic strategies (such as radioiodine). Currently, USA Food and Drug Administration has approved the use of sorafenib for metastatic differentiated thyroid cancer.

TSH Normalization in Bariatric Surgery Patients After the Switch from L-Thyroxine in Tablet to an Oral Liquid Formulation.

OBJECTIVE: Drug malabsorption is one of the potential troubles after bariatric surgery. Evidence for diminished levothyroxine (L-T4) absorption has been reported in patients after bariatric surgery. METHODS: This study reports 17 cases of hypothyroid patients [who were well replaced with thyroxine tablets (for >1 year) to euthyroid thyrotropin (TSH) levels before surgery (13 Roux-en-Y gastric bypasses (RYGB); 4 biliary pancreatic diversions (BPD))]. From 3 to 8 months after surgery, these patients had elevated TSH levels. Patients were then switched from oral tablets to a liquid L-T4 formulation (with the same dosage, 30 min before breakfast). RESULTS: Two-three months after the switch, TSH was significantly reduced both in patients treated with RYGB, as in those treated with BPD, while FT4 and FT3 levels were not significantly changed (RYGB group, TSH µIU/mL: 7.58 ± 3.07 vs 3.808 ± 1.83, P < 0.001; BPD group, TSH µIU/mL: 8.82 ± 2.76 vs 3.12 ± 1.33, P < 0.01). CONCLUSIONS: These results first show that liquid L-T4 could prevent the problem of malabsorption in patients with BPD and confirm those of previous studies in patients submitted to RYGB, suggesting that the L-T4 oral liquid formulation could circumvent malabsorption after bariatric surgery.

Pyrazolopyrimidine Derivatives as Antineoplastic Agents: with a Special Focus on Thyroid Cancer.

Tyrosine kinase inhibitors (TKIs) are molecules that compete with ATP on tyrosine kinase receptors (TKRs), blocking tyrosine kinase (TK) activation and then oncogenic pathways; they have been studied, and some of them are right approved for the treatment of many types of cancer. Among TKIs, one of the most explored chemical template is the pyrazolo[3,4-d]pyrimidine (PP) heterocyclic core, which proved to be a useful scaffold for the obtainment of effective compounds. Actually, derivatives belonging to this structural class show a large spectrum of activity, thus standing out as multi-target agents. Different PP compounds have been shown to act as: a) ABL inhibitors and antiproliferative agents against human leukemia cell lines; b) Src kinase inhibitors in neuroblastoma, medulloblastoma and osteosarcoma; c) Phospholipase D inhibitors in different neoplasias; d) Urokinase plasminogen activator inhibitors, in breast cancer. In thyroid cancer (TC), PP1 and PP2 (inhibitors of RET, Hck, lck, and fynT kinases, and a good inhibitor of c-Src and platelet-derived growth factor receptor) showed antineoplastic actvity in human papillary TC cell lines that carry spontaneous RET/PTC1 rearrangements. More recently, new derivatives, (R)-1-phenethyl-N-(1-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidin-4- amine, namely, CLM3 and CLM29, have been demonstrated to exert a multiple signal transduction inhibition (including the RET-TK, BRAF, EGFR, and with antiangiogenic activity), showing antineoplastic activity, in vitro and in vivo, in papillary dedifferentiated, medullary and anaplastic TC. These data have shown the antineoplastic activity of PP in different neoplasias, opening the way to a future clinical evaluation in human cancers.

Molecular Targeted Therapies of Aggressive Thyroid Cancer.

Differentiated thyroid carcinomas (DTCs) that arise from follicular cells account >90% of thyroid cancer (TC) [papillary thyroid cancer (PTC) 90%, follicular thyroid cancer (FTC) 10%], while medullary thyroid cancer (MTC) accounts <5%. Complete total thyroidectomy is the treatment of choice for PTC, FTC, and MTC. Radioiodine is routinely recommended in high-risk patients and considered in intermediate risk DTC patients. DTC cancer cells, during tumor progression, may lose the iodide uptake ability, becoming resistant to radioiodine, with a significant worsening of the prognosis. The lack of specific and effective drugs for aggressive and metastatic DTC and MTC leads to additional efforts toward the development of new drugs. Several genetic alterations in different molecular pathways in TC have been shown in the past few decades, associated with TC development and progression. Rearranged during transfection (RET)/PTC gene rearrangements, RET mutations, BRAF mutations, RAS mutations, and vascular endothelial growth factor receptor 2 angiogenesis pathways are some of the known pathways determinant in the development of TC. Tyrosine kinase inhibitors (TKIs) are small organic compounds inhibiting tyrosine kinases auto-phosphorylation and activation, most of them are multikinase inhibitors. TKIs act on the aforementioned molecular pathways involved in growth, angiogenesis, local, and distant spread of TC. TKIs are emerging as new therapies of aggressive TC, including DTC, MTC, and anaplastic thyroid cancer, being capable of inducing clinical responses and stabilization of disease. Vandetanib and cabozantinib have been approved for the treatment of MTC, while sorafenib and lenvatinib for DTC refractory to radioiodine. These drugs prolong median progression-free survival, but until now no significant increase has been observed on overall survival; side effects are common. New efforts are made to find new more effective and safe compounds and to personalize the therapy in each TC patient.

Sorafenib in the treatment of thyroid cancer.

Sorafenib has been evaluated in several Phase II and III studies in patients with locally advanced/metastatic radioactive iodine-refractory differentiated thyroid carcinomas (DTCs), reporting partial responses, stabilization of the disease and improvement of progression-free survival. Best responses were observed in lung metastases and minimal responses in bone lesions. On the basis of these studies, sorafenib was approved for the treatment of metastatic DTC in November 2013. Few studies suggested that reduction of thyroglobulin levels, or of average standardized uptake value at the fluorodeoxyglucose-PET, could be helpful for the identification of responding patients; but further studies are needed to confirm these results. Tumor genetic marker levels did not have any prognostic or predictive role in DTC patients.The most common adverse events observed included skin toxicity and gastrointestinal and constitutional symptoms. Encouraging results have also been observed in patients with medullary thyroid cancer. Many studies are ongoing to evaluate the long-term efficacy and tolerability of sorafenib in DTC patients.

Autoimmune and neoplastic thyroid diseases associated with hepatitis C chronic infection.

Frequently, patients with hepatitis C virus (HCV) chronic infection have high levels of serum anti-thyroperoxidase and/or anti-thyroglobulin autoantibodies, ultrasonographic signs of chronic autoimmune thyroiditis, and subclinical hypothyroidism, in female gender versus healthy controls, or hepatitis B virus infected patients. In patients with "HCV-associated mixed cryoglobulinemia" (MC + HCV), a higher prevalence of thyroid autoimmune disorders was shown not only compared to controls, but also versus HCV patients without cryoglobulinemia. Patients with MC + HCV or HCV chronic infection show a higher prevalence of papillary thyroid cancer than controls, in particular in patients with autoimmune thyroiditis. Patients with HCV chronic infection, or with MC + HCV, in presence of autoimmune thyroiditis, show higher serum levels of T-helper (Th)1 (C-X-C motif) ligand 10 (CXCL10) chemokine, but normal levels of Th2 (C-C motif) ligand 2 chemokine, than patients without thyroiditis. HCV thyroid infection could act by upregulating CXCL10 gene expression and secretion in thyrocytes recruiting Th1 lymphocytes that secrete interferon-γ and tumor necrosis factor-α. These cytokines might induce a further CXCL10 secretion by thyrocytes, thus perpetuating the immune cascade, which may lead to the appearance of autoimmune thyroid disorders in genetically predisposed subjects. A careful monitoring of thyroid function, particularly where nodules occur, is recommended in HCV patients.