The FDA’s Orphan Drug designation offers a special status to drugs or biologics designed to treat rare conditions. In the United States, a rare disease is one that impacts less than 200,000 people. Recently, biotechnology company Exicure, Inc. shared that its drug candidate cavrotolimod (AST-008) received Orphan Drug status for the treatment of Merkel cell carcinoma (MCC).
Cavrotolimod
So what is cavrotolimod? This therapy was created with Exicure’s proprietary Spherical Nucleic Acid (SNA) technology. Exicure describes the treatment as:
a toll-like receptor 9 agonist designed to activate the innate immune system and induce a potent anti-cancer immune response, especially in combination with checkpoint inhibitors.
Data from prior clinical trials showed that cavrotolimod, used in conjunction with pembrolizumab, was able to inhibit tumor growth. Exicure is still evaluating the treatment for patients with MCC or cutaneous squamous cell carcinoma (CSCC) in a Phase 2 clinical trial. Thus far, the treatment has been relatively safe and well-tolerated, with injection site reactions being one of the more common side effects.
Outside of Orphan Drug designation, cavrotolimod also received Fast Track designation for MCC and CSCC. With Orphan Drug status, Exicure will receive tax credits, waived fees, and up to 7 years of market exclusivity.
Merkel Cell Carcinoma (MCC)
According to merkelcell.org, Merkel cell carcinoma (MCC) is a rare and aggressive form of skin cancer also known as neuroendocrine carcinoma of the skin. MCC begins in Merkel cells, which merkelcell.org describes as:
touch cells [which] relay touch-related information such as texture and pressure to the brain. While they are present in human skin at varying levels according to body site, they are at highest density on the fingertips and lips/face where touch sensation is most acute.
While researchers are not exactly sure what causes MCC, many believe risk factors include Merkel cell polyomavirus, age (50+), having a history of skin cancer, excessive sunlight exposure, and having a weakened immune system. MCC usually appears as a flesh- or red-colored nodule on sun-exposed skin. Typically, this is on the head, neck, or face. In most cases, this nodule quickly grows and can spread to other areas on the body, such as the lymph nodes, bones, lungs, liver, or brain. Most commonly, the quickly-growing and painless nodules are the sole symptom of MCC.
If you see a mole or lesion which is growing quickly, which bleeds easily, or which changes in size or color, please see your doctor immediately. While MCC can be life-threatening, it is possible to treat if detected early.
