By Leonard Calabrese, DO

This year’s ACR was an amazing meeting with over 15,000 attendees and nearly 300 presentations, so it’s impossible to summarize this meeting succinctly. To many of us, this year could be considered the “Year of Vasculitis” with numerous high-impact presentations and one major breakthrough in the treatment of Giant Cell Arteritis (GCA).

MAINRITSAN and MAINRITSAN II

In terms of high-impact abstracts, the French Vasculitis Network presented several papers on the maintenance of remission in patients with ANCA-associated vasculitis. In a day two plenary, Benjamin Terrier, MD, presented long-term (60 months) follow-up of the MAINRITSAN trial, which compared Q5 month low dose (500 mg) rituximab to oral azathioprine. Consistent with the early analysis at 28 months therapy, rituximab continued to be superior with statistical benefits for survival. Now we have strong evidence of the validity of this strategy in selected patients.

In a second landmark presentation, Pierre Charles, MD, presented the long-awaited results of the MAINRITSAN II trial as a late breaker. Low-dose rituximab regimens were compared for maintenance remission in ANCA-associated vasculitis. One regimen was a fixed dose with an on-demand regimen of rituximab guided by return of circulating B cells and ANCA detectability and/or titer. The other group received the same dose at regular intervals. At 28 months, there was no significant difference in relapses between the two groups. Though there were numerically more relapses in the on-demand group (17 percent vs. 9.9 percent), these patients required fewer infusions and lower doses of rituximab. It remains to be seen how this strategy will work its way into practice.

GIACTA results a game-changer for GCA

Finally, the biggest hit of the meeting in the field of vasculitis was the plenary presentation by John Stone, MD, with results of the GIACTA trial. In this trial, 256 patients with GCA were randomized to glucocorticoids alone for 53 weeks, glucocorticoids alone for 26 weeks or similar regimens of glucocorticoids accompanied by tocilizumab, an IL6 blocker, in two different dose regimens.

The results of the trial were nothing less than striking, with both tocilizumab arms achieving superiority on all counts, with no increase in toxicity and dramatic steroid-sparing effects. GCA has long been a difficult disease to manage, as patients with GCA are elderly and often require long-term and high-dose glucocorticoids attended by significant toxicities to control the disease. Methotrexate and other drugs have been disappointing as potential steroid-sparing agents.

Tocilizumab a potent suppressor

Also presented were the follow-up results of a single-center, randomized controlled trial of tocilizumab in GCA, in which patients who were treated with tocilizumab for 52 weeks were observed after treatment termination. In observation, 55 percent of patients relapsed over about 14 months. Thus tocilizumab was named not a cure for GCA but rather a potent suppressor.

Alternatively, 45 percent of patients remained in long-term remission, offering hope that we may one day uncover determinates of therapeutic responsiveness. While many questions remain about the use and positioning of tocilizumab in the treatment scheme for GCA, the FDA has fast-tracked the drug based on these remarkable results.

Learning opportunities in vasculitis

Cleveland Clinic’s own Center for Vasculitis Care and Research will be holding a pre-symposium to the Biologic Therapies Summit VII, entitled Primary Vasculitidies: Best Practices and Future Advances. The pre-symposium on April 5, 2017 will address the substantial developments made in the field of vasculitis over the past several years as well as what the future may hold. Learn more and register today at www.ccfcme.org/primaryvasc17.

This activity has been approved for AMA PRA Category 1 Credit™.

Dr. Calabrese is Director of the R.J. Fasenmyer Center for Clinical Immunology in Cleveland Clinic’s Department of Rheumatic and Immunologic Diseases.