The FDA recently granted regulatory approval for tocilizumab (Actemra, Genentech), the first approved therapy for the treatment of adults with giant cell arteritis.
Tocilizumab, a humanized interleukin-6 (IL-6) receptor antagonist, already is approved to treat various autoimmune disorders including rheumatoid arthritis (RA).
GCA, a chronic and severe autoimmune condition that can result in vision loss (including irreversible blindness) and other systemic sequelae, is the common form of vasculitis in people over 50 years. It is characterized by an inflammation of the blood vessels branching off of the heart, including those supplying the scalp, neck, and arms.1
The eye care community is “well aware” of the devastating effects of GCA, also known as temporal arteritis, said Mark Robinson, MD, University of South Carolina Department of Ophthalmology, Columbia. “This disease is one of the well-known vision-threatening emergencies,” he added.
Permanent visual impairment may occur in about 20% of patients with GCA.2 Unfortunately, the cause of the disease is unknown, and no one single test is definitive.”
Before the tocilizumab approval, Dr. Robinson said the only successful treatment was high doses of glucocorticoids (usually prednisone) for many months, tapering to a moderate or lower doses for one to two years—if not longer.
But when patients taper off steroids, relapse rates can be high, said Anne Fung, MD, in private practice in San Francisco and associate group medical director, Genentech.
The lengthier amount of time spent on corticosteroids can lead to side effects, including hyperglycemia, insomnia, and bone fractures, she added.
Dr. Robinson noted GCA may initially present as a transient–but painless–vision impairment, or cause transient double vision. Symptoms that occur before or after vision loss are the onset of a new kind of headache, scalp tenderness, aching, and fatigue of the jaw while chewing (jaw claudication), weight loss, muscle aches, and fever.
“If suspicion is high enough based on the clinical presentation and laboratory values, the patient should be started on oral prednisone and referred for a temporal artery biopsy (perhaps bilaterally if the initial one is negative),” he said.