Can oclacitinib treat COVID-19?

What do JAK inhibitors do?

JAK inhibitors are a class of drugs used to treat conditions affecting the immune system, including cancers, allergies, and autoimmune disorders. JAK inhibitors work by blocking specific processes in the human body that affect inflammation. By inhibiting these processes, JAK inhibitors effectively reduce the body’s response to inflammation. Several JAK inhibitors, including tofacitinib (Xeljanz^®), baricitinib (Olumiant^®), and upadacitinib (Rinvoq^®), are currently approved by the US Food and Drug Administration (FDA) to treat conditions such as rheumatoid arthritis and ulcerative colitis. 

Unlike many other prescription anti-inflammatory medications such as adalimumab (Humira^®) and etanercept (Enbrel^®), which are only given by injection, JAK inhibitors are available as tablets or oral solutions. The ability to take these medications by mouth makes JAK inhibitors an attractive option for many patients who suffer from inflammatory or autoimmune conditions.

Can JAK inhibitors be used for COVID-19?

COVID-19 infection can result in widespread inflammation throughout the human body, including the development of a condition called “cytokine storm,” which can cause severe illness or death. Because of the severe inflammation that often accompanies COVID-19 infection, JAK inhibitors have been explored as potential treatments for COVID-19. In patients hospitalized with moderate to severe COVID-19 infection, use of the JAK inhibitor baricitinib has been shown to improve lung function and shorten recovery times from the virus. In 2020, the FDA granted an Emergency Use Authorization for baricitinib for patients aged 2 years and older who are hospitalized with COVID-19 infection requiring oxygen treatment.

Do JAK inhibitors have side effects?

JAK inhibitors are associated with significant side effects, including an increased risk of serious infections and blood clots. Patients who take JAK inhibitors might also be at increased risk for developing certain types of cancer. Doctors who prescribe JAK inhibitor drugs will generally monitor their patients closely for these conditions and order blood testing at regular intervals.

What is oclacitinib used for?

Since animals can also experience inflammation and allergies, JAK inhibitor drugs have been developed for use in animals. Oclacitinib (Apoquel^®) is a JAK inhibitor used for the treatment of allergic skin conditions and itching in dogs. It is available in an oral formulation for dogs. Oclacitinib has not been studied for use in humans and is not approved by the FDA for use in humans. 

In dogs, oclacitinib is associated with serious side effects, including vomiting, diarrhea, lethargy, seizures, some cancers, and death. Given the concerning side effect profile of oclacitinib in animals and the lack of human studies regarding this drug, people should not take this veterinary drug. In addition, there is no evidence to suggest that oclacitinib is effective in treating or preventing COVID-19 infections.