A study assessing the use of tumor necrosis factor (TNF) alpha inhibitor biosimilars in France found that the biosimilar penetration rate was higher for infliximab compared to etanercept and adalimumab. The authors said they aimed to understand the key drivers for biosimilar use to improve biosimilar uptake in France.
A study, published in Scientific Reports, assessing the use of tumor necrosis factor alpha (TNF-α) inhibitor biosimilars in France found that the biosimilar penetration rate was higher for infliximab compared to etanercept and adalimumab. The authors said they aimed to understand the key drivers for biosimilar use to improve biosimilar uptake in France.
Anti-TNF biologics have “revolutionized the therapeutic care in chronic inflammatory diseases,” according to the authors. In France, infliximab, etanercept, and adalimumab entered the market in 2000, 2003 and 2005. Biosimilars referencing these molecules have been available in France since 2015, 2016, and 2018.
The authors used a comprehensive French claims database including every patient who received anti-TNF therapy from January 2015 to September 2021, a total of 217,756 patients, 115,656 of whom initiated treatment during the study period. They assessed both initiation of anti-TNF therapy and switching between originators and biosimilars.
Higher Penetration Rate of Infliximab Biosimilars Compared to Adalimumab and Etanercept
Initiations of adalimumab biosimilars increased from 14,711 in the first year after market entry to 20,198 in the second year. Etanercept initiations were relatively stable following market entry, with 6639 in year 1 and 5341 in year 4. Infliximab initiations were similarly stable, with 5460 in year 1 and 5041 in year 5.
The rate of biosimilar uptake in France increased faster for infliximab than adalimumab and etanercept. Biosimilars represented 78% of infliximab initiations in year 2 after market entry, compared to 60% for adalimumab and 51% for etanercept. After 7, 6, and 3 years, biosimilar initiation rates were 94% for infliximab, 66% for etanercept, and 60% for adalimumab. By the end of the study, biosimilars represented 81% of infliximab prescriptions, 39% of etanercept prescriptions, and 37% of adalimumab prescriptions.
The authors noted that infliximab biosimilars were the first to come to market, and infliximab prescription and delivery are managed at the hospital level rather than the pharmacy level. They reasoned that these factors likely contributed to the higher penetration of infliximab compared to the other anti-TNF molecules.
The study also revealed that the condition treated and clinician specialty “had an important impact on biosimilar versus originator initiation.” Infliximab biosimilar initiation rates were similar among different specialties. However, for etanercept and adalimumab, biosimilars were more frequently used in rheumatology, followed by gastroenterology then ophthalmology.
“A Significant Number of Patients Alternating Between Originator and Biosimilar Products”
Switching to a biosimilar was more common among infliximab users (35%) than etanercept (10%) and adalimumab (6%) users who initiated therapy with the reference product during the study period. The authors found more patients than expected had switched from one of the originators to a biosimilar and back to the originator, and a significant number of patients who switched between molecules. They reported that 22%, 37%, and 32% of patients receiving infliximab, etanercept, and adalimumab at the start of the study period switched to a biosimilar then back to an originator. They said this prevalent alternation between originator and biosimilar products suggests “potential switches due to product availability, and thus non-medical isolated switches, or perceived total exchangeability between products.”
The authors concluded that penetration rate of TNF inhibitor biologics varied according to the molecule and the disease treated. To improve anti-TNF biosimilar uptake, they recommended encouraging biosimilar prescription, especially by dermatologists and gastroenterologists, and for molecules delivered at the retail pharmacy level (etanercept and adalimumab).
Jourdain H, Hoisnard L, Sbidian E, Zureik M. TNF-alpha inhibitors biosimilar use in France: a nationwide population-based study using the French National Health Data System. Sci Rep. 2022;12(1):19569. doi:10.1038/s41598-022-24050-7