Actemra for Giant Cell Arteritis
Dr. Jeffrey Landis, April 2019
Giant cell arteritis is the most common primary vasculitis in the US and Europe. Patients develops signs of systemic inflammation and poor blood flow in the extracranial arteries. 80-90% of the time, giant cell arteritis can be detected in the superficial temporal arteries. It is also commonly found in the vertebral artery and arteries to the eye. The temporal artery may feel thickened, tender, nodular, and have decreased pulses.
There are many symptoms of giant cell arteritis. It can cause throbbing, sharp or dull headaches. Some patients have scalp tenderness. Due to the low blood flow, they can develop patchy hair loss and scalp ulcerations over these areas of the scalp. Jaw claudication may also occur. This is pain in the muscles that work the jaw while chewing food due to the lack of blood flow. Claudication of the tongue can occur, but this is rare. Patients can also develop fatigue, weight loss, fever, night sweats, and chills. Polymyalgia rheumatica is frequently seen with pain and morning stiffness in the hips and shoulders.
Vision loss is the most feared complication of giant cell arteritis. It is a sudden, painless, and permanent complete vision loss most of the time. With quick action, aspirin and pulse steroids have helped return vision, but this is a rare occurrence.
Diagnosis is made when a patient is over 50 years old and experiences a combination of unexplained headaches, loss of vision, signs of ischemia in the extracranial region, jaw claudication, polymyalgia rheumatica and an elevated sedimentation rate (on average >50). When giant cell arteritis is suspected, the patient is immediately started on prednisone 60mg a day and daily aspirin. The patient is then referred for temporal artery biopsy. When the patient is diagnosed with giant cell arteritis, the prednisone is slowly tapered off over the next 1-2 years depending on symptoms and lab values.
Some patients have difficulty tapering off the prednisone or even getting down to low doses of prednisone. Recently, Actemra has been approved for the treatment of giant cell arteritis. This infusion is typically infused over the course of an hour, and it is given every 4 weeks. When effective, the patient can taper off the prednisone. Prednisone is known for its high incidence of side effects. Some will be known to the patient, like weight gain and high sugar levels, if they are a diabetic. Some they will not know about, like osteoporosis, until it is too late.
In the Actemra studies for giant cell arteritis, 56% of the patients receiving Actemra were responders and 14% on prednisone alone were labeled as responders at week 26. The prednisone tapers for each group were tapered to 0mg at week 26, which is fast for giant cell arteritis. Those maintaining remission over the 26 weeks were labeled responders. The overwhelming response to Actemra is logical as Actemra inhibits IL-6 and giant cell arteritis is an IL-6 driven disease.
Side effects to Actemra are uncommon but can include infections, malignancy, allergic reaction, infusion reactions, intestinal perforation, multiple sclerosis, low blood counts, high cholesterol, and elevated LFT’s. Of these side effects, I have seen elevated LFT’s, low white blood counts and allergic reactions. The patient is monitored with routine labs to screen for any developing side effects or suggestions that a side effect may occur.