FDA Grants Orphan Drug Designation to Selumetinib for Thyroid Cancer

Selumetinib (AZD6244, ARRY-142886) has received Orphan Drug Designation status by the US Food and Drug Administration (FDA) to be used as an adjuvant treatment in patients with stage III or IV differentiated thyroid cancer (DTC).

This drug was granted Orphan Drug Designation which means that certain drugs and biologics, which are defined as those intended for the safe and effective treatment, diagnosis, or prevention of rare diseases or disorders that affect fewer than 200,000 people in the United States.

Selumetinib is classified as a mitogen-activated protein kinase enzyme (MEK) inhibitor, which is a drug that inhibits the enzymes MEK1 and/or MEK2. It can be used to affect the MAPK/ERK pathway which is often overactive in certain cancer types.

Some patients do not benefit from treatment with adioactive iodine (RAI) if 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 intention that this may become a new treatment for patients whose thyroid cancer cells do not respond well to RAI.

“Uptake of RAI is crucial for patients with thyroid cancer where no other therapies have proven beneficial,” said Sean Bohen, Executive Vice President, Global Medicines Development and Chief Medical Officer, at AstraZeneca, in a press release.

“Selumetinib could significantly enhance currently available treatment options for these patients. The Orphan Drug Designation is an important achievement as we advance our development plans for this potential treatment in differentiated thyroid cancer,” Bohen added.

Although the death rate from thyroid cancer remains relatively low, compared with other cancer types, the number of those diagnosed annually is fairly substantial. About 62,450 new cases of thyroid cancer (49,350 in women, and 19,950 in men) will be diagnosed this year and about 1,980 deaths from thyroid cancer (1,070 women and 910 men) will occur, according to the American Cancer Society. The uptick in diagnoses may be due to improved diagnostic tools.

In addition to thyroid cancer, selumetinib is currently being tested in the SELECT-1 trial, a phase III trial of patients with KRAS-mutant advanced non-small cell lung cancer and in a phase II registration trial of pediatric and adolescent patients with neurofibromatosis Type 1.