Oncoprescribe Blog: Pazopanib in Thyroid Cancer

December 6th, 2010

Pazopanib (Votrient) is a Tyrosine Kinase Inhibitor (TKI) that  targets Vascular Endothelial Growth Factor Receptor (VEGFR), Platelet-Derived Growth Factor Receptor (PDGFR), c-kit and Ret. This drug is presently approved by the FDA for the treatment of metastatic renal cell carcinoma. Data presented at the ASCO 2010 demonstrated impressive responses using Pazopanib (Votrient) in advanced radioiodine-refractory Follicular, Papillary and even Hurthle cell thyroid carcinomas.

This is an important step forward, in addressing this malignancy, as the benefit seen with chemotherapy is at best marginal, in the subset of patients studied. VEGF (Vascular Endothelial Growth Factor) appears to play a very important role in the pathogenesis of Thyroid Carcinomas. Learning and targeting the molecular mechanism of a malignancy is clearly the wave of the future.

Oncoprescribe Blog: Vandetanib (Zactima) in Medullary Thyroid Cancer

December 1st, 2010

Medullary Thyroid Cancer accounts for about 6% of all thyroid cancers. This cancer originates from the parafollicular cells, also called C cells, of the thyroid. Calcitonin is a hormone produced by the C cells. For this reason, measuring serum calcitonin following complete resection of Medullary Thyroid Carcinoma can be helpful in diagnosing recurrent disease.

There is presently no active treatment approved by the FDA,  for the treatment of advanced Medullary Thyroid Carcinoma (MTC). A new oral Tyrosine Kinase Inhibitor (Vandetanib) has shown promising results and may soon become available. This agent is a dual inhibitor and targets the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR). It also appears to inhibit RET-tyrosine kinase activity, an important  driver of cell growth in MTC.

Results from a double blind phase III trial (ZETA study) presented at ASCO 2010, showed that treatment with Vandetanib significantly extended progression free survival with a 54% reduction in the rate of disease progression compared to placebo.

Vandetanib (Zactima) is very likely to be studied in other solid tumors given its ability to target multiple receptors. Stay Tuned.