All patients with active giant cell arteritis (GCA), whether they are a new patient or a relapsing patient, would benefit from treatment with tocilizumab and corticosteroids.
A two-year extension to the original GiACTA trial clearly showed that weekly treatment significantly delayed the time to first flare and reduced total glucocorticoid exposure in both new-onset and relapsing GCA.
The extension study, published in Rheumatology, also showed that a weekly dose (TCZ QW) was more effective at delaying flare than every-other-week dosing (TCZ Q2W).
It found that in patients with new-onset and relapsing disease the median time to first flare was longer in the TCZ QW group (577 and 575 days, respectively) compared to the TCZ Q2W arm (479 and 428 days) and the steroid-only control group (179 and 224 days).
Median cumulative glucocorticoid dose was also lowest in the once-weekly dose, at 3,068 mg and 2,191 mg in patients with new-onset and relapsing disease respectively, compared to 4,080mg and 2,353mg in the every-other-week dosing schedule and 4,639mg and 6,178mg with steroid-only control arm.
As well, the study found that a higher proportion of patients in the once-weekly group did not experience flares over the three-year study period (48% vs 31% for TCZ Q2W and 30% for placebo).
Among patients with new-onset disease, the figures were 49%, 27% and 28%, respectively, compared to 47%, 35% and 31%, respectively, in patients with relapsing disease.
Dr Daman Langguth, Chair of the ANZVASC Clinical Trials Committee, told the limbic that many clinicians have started using tocilizumab for new-onset GCA patients.
The new findings from Part 2 of the GiACTA trial were therefore useful in reinforcing current practice.
“I think it gives more data to say you should treat every person straight away with this drug – at the time of diagnosis or on relapse ideally,” he said.
“We know now that after some significant time, for several years afterwards, patients can remain in remission off the drug.”
However the problem in Australia was a PBS restriction that patients can only receive tocilizumab once.
Dr Langguth said the ARA would be advocating for a change in the PBS listing, especially given there were no other effective treatments for GCA.
“Why can you only have it once when it is a relapsing disease? In every other disease, if you stop treatment and have a relapse and you fulfil the criteria, you go back on treatment.”
“Steroids are an alternative; they are just not a very good one.”
He said methotrexate works for some people while leflunomide and cyclophosphamide may also help.
“But anything to get the corticosteroid exposure down is a good thing.”
“It’s the steroids that are really the risk factor, not the tocilizumab which increases infection. Steroids are a magnifier and they don’t just cause infection but bone loss, cataracts, skin changes, mood changes, etcetera.”
Dr Langguth said there were some limitations to the open label extension study including relatively small numbers and wide confidence intervals, however it was the largest RCT in GCA to date.
“It’s clear that weekly dosing leads to less relapse over time. So when you treat them for a year and stop, some people remain in remission for quite a long time.”
“There is still a lack of knowledge about what to do at the end of the first year. Do you keep going? Do you stop? I’ve had some patients go into remission and they stop the drug, whereas other patients continue…it’s roughly 50/50 whether they stay in remission or not.”
As reported recently in the limbic, GCA is one of the priority conditions for tocilizumab during the COVID-19 related shortage.