Switching from originator infliximab to a biosimilar, CT-P13 (Inflectra), does not result in any change in efficacy or safety in patients with inflammatory arthritis up to 18 months, new results from the NOR-SWITCH extension trial show.
Presenting findings from a six-month open label follow up of the 52-week NOR-SWITCH trial, researchers from Norway told delegates attending Digestive Diseases Week 2018 in Washington last week that there were no significant differences in the key outcomes of disease worsening or remission for patients with RA, spondyloarthritis or psoriatic arthritis.
The original study findings, published in 2017, showed no difference at 52 weeks between 482 patients randomised to infliximab or CT-P13. In the open label extension, the remaining patients taking infliximab were switched to CT-P13 and followed for a further 26 weeks.
In the Extension phase, disease worsening rates were not significantly different for patients with RA in the maintenance group on CT-P13 (9/26, 34.6%) or those in the switching group from originator infliximab (6/27, 22.2%). Disease worsening rates were also not significantly different for patients with spondyloarthritis (3/38, 7.9% vs 2/28, 7.1% for maintenance vs switching). Disease worsening rates in patients with psoriatic arthritis favoured maintenance over switching (1/8, 12.5% vs 3/9, 33.3%) but the absolute numbers were low.
The overall rates of disease worsening for all conditions (including IBD and psoriasis patients) were 16.8% for maintenance vs 11.6% for switching.
Disease remission rates also showed no significant difference for the switch group vs the maintenance group for RA (63% vs 57.7%), sponyloarthritis (21.4% vs 18.4%) or psoriatic arthritis (55.6% vs 62.5%).
Rates of adverse events were similar for the maintenance and switch groups (44% vs 40%), and there were serious adverse events reported for 7% and 4% of patients in each group, respectively.
Immunogenicity rates were also not significantly different between grips, with 6.6% of patients in the maintenance group and 5.5% in the switch group showing anti-drug antibodies after 26 week extension period.
Study lead investigator Dr Kristin Jorgensen of Akershus University Hospital, Norway, said the latest results from NOR-SWITCH confirm that switching from originator to biosimilar is safe.
“Short versus long term treatment with CT-P13 is comparable regarding efficacy, tolerability and immunogenicity,” she said.
“These results support switching from originator infliximab to CT-P13 but we recommend caution in generalising these trends to other biologic agents, and further studies are needed to investigate multiple switches between biologic agents,” she added.
The study was funded by the Norwegian Ministry of Health and Care Services and the co-investigators said they had received grants and fees from marketers of originator and biosimilar products.
In a DDW 2018 panel discussion on biosimilars, Dr Peter Lakatos, a gastroenterologist at McGill University, Montreal, said the mounting evidence combined with Europe experience with biosimilars supported the interchangeability of biologics.
He pointed out that in his home country of Hungary, mandatory (non-medical) multiple switching between infliximab and its biosimilar did not results in any change in efficacy or safety.
“In Europe, we have seen biosimilars can help address patients access and healthcare affordability,” he concluded.
In Australia, Remicade is the originator infliximab brand, but biosimilar Renflexis and Inflectra have been approved for PBS listing with “uptake drivers” of streamlined authority to encourage their prescribing.