What is the diagnosis and treatment of Giant Cell Arteritis (GCA)?

From the Guidelines

Giant Cell Arteritis (GCA) is a medical emergency requiring immediate treatment with high-dose corticosteroids to prevent vision loss, and the recommended initial treatment is prednisone 40-60mg daily, started immediately upon clinical suspicion without waiting for biopsy results, as recommended by the 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of giant cell arteritis and Takayasu arteritis 1.

Initial Treatment

The initial treatment should be started immediately, without waiting for biopsy results, to prevent vision loss.

• The recommended initial dose of prednisone is 40-60mg daily (or weight-based at 1mg/kg/day) 1.
• For patients with visual symptoms, methylprednisolone 500-1000mg IV daily for 3 days may be given before transitioning to oral prednisone 1.

Tapering and Maintenance

• The steroid dose should be maintained for 2-4 weeks until symptoms resolve and inflammatory markers normalize, then gradually tapered over 12-18 months 1.
• Temporal artery biopsy should be performed within 1-2 weeks of starting treatment to confirm diagnosis 1.

Adjunctive Therapy

• For patients requiring prolonged steroid therapy or with relapsing disease, steroid-sparing agents like methotrexate (15-25mg weekly) or tocilizumab (162mg subcutaneously weekly) may be added, as recommended by the 2018 update of the EULAR recommendations for the management of large vessel vasculitis 1.
• The decision to use adjunctive immunosuppressive therapy in the individual patient should be balanced against potential risks for treatment-related complications 1.

Monitoring and Prevention

• Regular monitoring of symptoms, inflammatory markers (ESR, CRP), and potential steroid side effects is essential throughout treatment 1.
• Long-term steroid use requires bone protection with calcium (1200mg daily), vitamin D (800-1000 IU daily), and often a bisphosphonate 1.

From the FDA Drug Label

The safety of subcutaneous tocilizumab has been studied in one Phase III study (WA28119) with 251 GCA patients. The overall safety profile observed in the tocilizumab-SC treatment groups was generally consistent with the known safety profile of tocilizumab. There was an overall higher incidence of infections in GCA patients relative to RA patients.

The treatment of Giant Cell Arteritis (GCA) with tocilizumab has been studied, and the overall safety profile was consistent with the known safety profile of tocilizumab.

• The incidence of infections was higher in GCA patients compared to RA patients.
• The rate of infection/serious infection events was 200.2/9.7 events per 100 patient years in the tocilizumab-SC weekly group and 160.2/4.4 events per 100 patient years in the tocilizumab-SC every other week group.
• Tocilizumab can be used to treat GCA, but patients should be monitored for infections 2.

From the Research

Treatment of Giant Cell Arteritis

• The main treatment for giant cell arteritis (GCA) is corticosteroids, which are used to reduce inflammation and prevent complications 3, 4, 5, 6, 7.
• High-dose corticosteroid therapy is often prescribed, especially in cases of severe ischemic complications, although the evidence for its effectiveness is limited 4, 5.
• Methotrexate has been shown to have a moderate corticosteroid-sparing effect and can be used as an alternative to corticosteroid therapy alone in patients with GCA 3, 6, 7.
• Tocilizumab, an anti-IL-6 receptor antibody, is also available as a treatment option for GCA and has been shown to be effective in reducing the risk of relapse 6, 7.
• Aspirin may be beneficial in patients with ischemic complications or multiple cardiovascular risk factors, although its benefit-to-risk ratio needs to be carefully considered 4, 6.

Management of Corticosteroid-Related Adverse Events

• Corticosteroid-related adverse events, such as hypertension, diabetes mellitus, osteoporosis, psychosis, peptic ulcer disease, and infection, are common in patients with GCA 5.
• Supplementation with calcium, vitamin D, bisphosphonate therapy, antimicrobial prophylaxis, and initiation of a proton pump inhibitor or Histamine H2-receptor antagonist may be necessary to prevent these adverse events 5.
• Gradual tapering of corticosteroid dose over months is recommended to minimize the risk of complications 6.

Prevention of Cardiovascular Events

• Prevention of cardiovascular events is an important aspect of the treatment of GCA, and aspirin (75-100mg/day) may be recommended during the first month of treatment or longer in case of occurrence of an ischemic complication 6.
• Each patient treated for GCA should receive prevention of osteoporosis with respect to usual recommendations 6.