GiACTA: Giant cell arteritis remission maintained in 42% of patients after drug cessation
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A substantial proportion of patients who received tocilizumab for giant cell arteritis for 1 year remain in drug-free remission throughout the 2 years after ceasing therapy, according to data published in The Lancet Rheumatology.
“In part one of the Giant Cell Arteritis Actemra (GiACTA) trial, a 52-week randomized, double-blind trial, treatment with tocilizumab (an interleukin-6 receptor [IL-6R] antagonist) plus blinded prednisone taper was more effective than was placebo plus blinded prednisone taper for inducing sustained remission; however, the duration of the effects of tocilizumab is unknown,” John H. Stone, MD, of Massachusetts General Hospital and Harvard Medical School, and colleagues wrote. “Patients with giant cell arteritis might experience continued benefit after discontinuation of successful initial therapy.”
To analyze efficacy maintenance 1 year after tocilizumab (Actemra, Genentech) discontinuation in patients in remission from GCA, as well as the effectiveness of retreatment after relapse and the long-term, glucocorticoid-sparing impact of the drug, Stone and colleagues conducted part two of the GiACTA trial — an open-label extension phase. In part one, 251 patients randomized 2:1:1:1 to receive 162 mg of subcutaneous tocilizumab once per week or every other week, combined with a 26-week prednisone taper, or a placebo plus prednisone taper, over a period of 26 or 52 weeks.
Patients who achieved clinical remission at 1 year ceased masked injection, representing the end of part one. For part two, the researchers chose the treatments based on their own discretion. Possibilities included no treatment, tocilizumab, glucocorticoids or methotrexate, or combinations of these, for 2 years. In all, 215 patients participated in part two, including 81 who had been randomly assigned tocilizumab once per week and achieved remission after 1 year in part one. Among these 81 participants, 59 began part two with no treatment.
Exploratory objectives for part two included efficacy maintenance, based on clinical remission, as well as cumulative glucocorticoid dose and long-term safety, through 2 years.
According to the researchers, among the 59 patients in remission who began part two on no treatment, 42% maintained tocilizumab-free and glucocorticoid-free clinical remission through week 104. Median cumulative glucocorticoid doses over 3 years were 2,647 mg (95% CI, 1,987-3,507) for tocilizumab once per week, 3,948 mg (95% CI, 2,352-5,186) for tocilizumab every other week, 5,277 mg (95% CI, 3944-6685) for placebo with a 26-week prednisone taper, and 5,323 mg (95% CI, 3,900-6,951) for placebo with a 52-week prednisone taper.
Among patients who relapsed in part two, retreatment with tocilizumab restored clinical remission, with a median time to remission of 15 days for the 17 participants who received tocilizumab alone, and 16 days for the 36 who received tocilizumab plus glucocorticoids. Among the 27 participants who were retreated with glucocorticoids alone, the median time to remission was 54 days. The researchers report no new or unexpected safety findings.
“Randomization to tocilizumab plus prednisone from the outset of therapy had an effect on treatment course and cumulative glucocorticoid use for 3 years,” Stone and colleagues wrote. “Giant cell arteritis remains a chronic disease that entails ongoing management and careful vigilance for disease relapse, but continuous indefinite treatment with immunosuppressive drugs is not required for all patients.”
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