AstraZeneca announced that the U.S. FDA has granted Orphan Drug Designation for the investigational MEK 1/2 inhibitor, selumetinib (AZD6244, ARRY-142886) for adjuvant treatment of patients with stage III or IV differentiated thyroid cancer (DTC).  DTC is diagnosed in approximately 60,000 people in the US each year, and radioactive iodine (RAI) is recommended for those with known/suspected metastases at diagnosis and those at high risk of recurrence. A small proportion of patients do not benefit from currently available treatment with RAI because they do not express sufficient sodium/iodine symporter (NIS) which is important for RAI uptake into thyroid cells. Selumetinib is being tested for its ability to increase expression of NIS with the potential to add a treatment option for patients who do not respond well to RAI.

Selumetinib inhibits the MEK pathway in cancer cells to prevent tumour growth. It is being tested in the Phase III ASTRA trial in patients with DTC who are at high risk of recurrence.