High Treatment Retention Following Biosimilar-to-Biosimilar Switch in Denmark

A real-world study in Denmark investigated retention of therapy after a nationwide mandatory switch from one infliximab biosimilar (CT-P13, Remsima; Celltrion Healthcare) to another (GP1111, Zessly; Sandoz) in patients with inflammatory arthritis. The investigators reported higher retention of GP1111 therapy among originator-experienced patients and those with lower disease activity at the time of the switch.

According to the authors, uptake of biosimilars in rheumatology is limited by a lack of real-world evidence on biosimilar-to-biosimilar switching. They wrote that although findings from some real-world studies on inflammatory bowel disease and psoriasis have been published, the current evidence on switching between biosimilars in inflammatory arthritis is “very limited.”

CT-P13 was the first infliximab biosimilar approved in the European Union in 2013 and the United States in 2016, and GP1111 was approved by the European Medicines Agency in 2018 following a phase III trial in rheumatoid arthritis (RA). Denmark instituted a mandatory switch from the infliximab reference product to CT-P13 in 2015, and a switch from CT-P13 to GP1111 in 2019. Clinical outcomes are monitored in Denmark’s nationwide registry of patients with rheumatologic diseases receiving biologics (DANBIO).

The study included 1605 patients, 685 with RA, 314 with psoriatic arthritis (PsA), and 606 with axial spondyloarthritis (AxSpA). Outcomes were reported for originator-naive (n = 1171) and originator-experienced (n = 434) patients.

Overall, originator-naïve patients were younger, had shorter disease duration, and had fewer comorbidities compared to originator-experienced patients. In the originator-naïve group, objective disease markers were higher and fewer patients were in remission.

GP1111 Retention Varied by Originator Experience, Disease Activity

One-year retention rates of GP1111 treatment were 83% among originator-naïve patients and 92% among originator-experienced patients. Among the 3 indications, the retention rates were 80% to 87% in originator-naïve and 90% to 96% in originator-experienced patients. The authors commented that similar retention rates have been observed in randomized controlled trials and observational studies for the infliximab reference product and CT-P13.

In RA and PsA, the risk of GP1111 treatment withdrawal was lower in originator-experienced compared to originator-naïve patients (RA: HR, 0.36; PsA: HR, 0.23). There was no significant difference in AxSpA. Higher baseline disease activity was associated with a higher risk of treatment withdrawal in all 3 indications.

In all 3 diseases, for both originator-naïve and experienced patients, disease activity was stable from 4 months prior to 4 months after the switch, with changes “close to zero for all measures with no statistically significant differences.”

Regarding safety, the investigators said that the proportion of patients who discontinued treatment due to adverse events “was similar to those previously reported in other real-world studies of biosimilar infliximab.” However, details on adverse events “could not be explored due to lacking data in DANBIO.”

The authors concluded that 1-year retention of therapy was high in both originator-naïve and experienced patients following a nationwide biosimilar-to-biosimilar switch. They added the higher retention rates in originator-experienced patients and those with low disease activity suggest that outcomes were “affected by patient-related rather than drug-related factors.”

Furthermore, they concluded switching from CT-P13 to GP1111 was effective and safe, and they wrote that their findings provide “important knowledge regarding real-life effectiveness for different switch scenarios among patients with inflammatory arthritis.”

Reference

Nabi H, Hendricks O, Jensen DV, et al. Infliximab biosimilar-to-biosimilar switching in patients with inflammatory rheumatic disease: clinical outcomes in real-world patients from the DANBIO registry. RMD Open. 2022;8(2):e002560. doi: 10.1136/rmdopen-2022-002560