Cabozantinib, a medication for the treatment of medullary thyroid cancer, has shown promising results in final-stage testing. Until now, there was no medication available in Belgium for treating this rare form of thyroid cancer. Dr. Patrick Schöffski, professor of oncology at the University of Leuven (KU Leuven), presented the results at the annual meeting of the American Society of Clinical Oncology in early June.
Medullary thyroid cancer accounts for 5 to 10 per cent of all malignant thyroid cancers. Medullary thyroid cancer occurs when the C-cells in the thyroid gland – and not the thyroid cells themselves – become malignant. C-cells produce the hormone calcitonin and regulate calcium content in the blood and bones. Medullary thyroid cancer can metastasise to the lymph nodes, lungs and bones. Treatment consists of surgical removal of the thyroid and of the lymph nodes in the neck. Until now, only palliative treatment was available for patients with progressive, unresectable, locally advanced or metastatic medullary thyroid cancer.
In an international trial in which University Hospitals Leuven participated, the effect of the drug cabozantinib was studied in patients with advanced, aggressive medullary thyroid cancer. Cabozantinib, which is available in pill form, is a molecule that inhibits the growth of blood vessels in a tumour. 330 patients from 74 hospitals in 25 countries were screened in the double-blind, randomised trial; two-thirds were given cabozantinib and one-third received a placebo. A significant reduction in tumour size was observed in 28 per cent of cabozantinib-treated patients compared with zero per cent in placebo-treated patients. In the cabozantinib group, 47 per cent of patients were stable (without relapse) after one year compared with only 7.2 per cent in the placebo group. In patients who experienced a relapse, relapse occurred after 11.2 months on average in cabozantinib-treated patients. For placebo-treated patients, the average was 4 months.
“The good news is not only the drug’s effectiveness, but also the duration of that effect: in cases where the tumour is significantly reduced, reduction persists for a median of 14.6 months. That is an exceptionally good result in comparison with the disease’s rapid evolution in the placebo group of this trial. Additionally, the results are independent of patients’ past treatments, be it chemotherapy, radiation or other medications. The drug is also effective against both the genetic variant of medullary thyroid cancer and the spontaneously occurring variant,” explains Professor Schöffski.
The biotechnology company Exelixis, which sponsored the trial, is currently pursuing certification by the Food and Drug Administration in theUnited Statesand the European Medicines Agency inEuropeto bring cabozantinib to the market.