The purpose of precision cancer medicine is to define the genomic alterations in the cancers DNA that are driving that specific cancer. Precision cancer medicine utilizes molecular diagnostic testing, including DNA sequencing, to identify cancer-driving abnormalities in a cancer’s genome. Once a genetic abnormality is identified, a specific targeted therapy can be designed to attack a specific mutation or other cancer-related change in the DNA programming of the cancer cells. Precision cancer medicine uses targeted drugs and immunotherapies engineered to directly attack the cancer cells with specific abnormalities, leaving normal cells largely unharmed. Precision medicines are being used for the treatment of advanced thyroid cancer and patients should ask their doctor about whether testing is appropriate. The following precision cancer medicines have shown promise.
Tafinlar & MeKinist: Up to 44 percent of papillary thyroid cancer patients have a genetic mutation called BRAF that can be specifically targeted by existing cancer drugs. The BRAF gene belongs to a class of genes known as “oncogenes,” which send signals to normal cells that cause them to become cancerous. Studies show that Tafinlar alone or combined with MeKinist are well tolerated by patients, resulting in a 50 to 54 percent response rate among the patients advanced BRAF-mutated papillary thyroid cancer.1
Lenvatinib: As an oral anti-angiogenic therapy that targets new blood vessel growth, lenvatinib can “starve” cancer of the nutrients it needs to grow. Overall 65% of refractory thyroid cancer patients experienced a partial or complete disappearance of their cancer following treatment with levatinib. They survive on average 18.3 months without cancer progression compared to 3.6 months for individuals not treated with levatinib.2
Cometriq (cabozantinib) Although medullary thyroid cancers only account for approximately 2-3% of all thyroid cancers they tend to have a somewhat worse prognosis than more common types of thyroid cancer. Cometriq is a precision cancer medicine – a tyrosine kinase inhibitor. It targets specific biological pathways that contribute to the growth of several types of cancer, including the receptor tyrosine kinase RET as well as MET and VEGFR2. The drug is approved for the treatment of metastatic medullary thyroid cancer.
Nexavar (sorafenib): Differentiated thyroid cancer is the most common type of thyroid cancer and can often be cured with surgery and radioactive iodine (RAI) treatment. In some cases, however, the cancer is resistant to RAI. RAI-resistant thyroid cancers have had few effective treatment options.
Nexavar is an oral medicine that works by inhibiting certain proteins that contribute to cancer growth. It has been approved for use in patients with locally recurrent or metastatic, progressive differentiated thyroid cancer that no longer responds to RAI treatment because nexavar increased progression-free survival by 41 percent compared to treatment with a placebo.3
Sutent (sunitinib): Sutent is a targeted therapy that is approved for the treatment of several cancers. It works by inhibiting multiple proteins in cancer cells to limit cancer cell growth and division and is active in the treatment of thyroid cancer.4
2 Schlumberger M, Makoto T, Wirth L, et al. The New England Journal of Medicine; 372:621-630 February 12, 2015.
3 FDA approves Nexavar to treat type of thyroid cancer. [FDA News Release]. U.S. Food and Drug Administration website. Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm376443.htm
4 Advanced Thyroid Cancer Responds to Targeted Therapy with Sunitinib [press release]. Endocrine Society website. Available at: https://www.endocrine.org/news-room/current-press-releases/advanced-thyroid-cancer-responds-to-targeted-therapy-with-sunitinib.