Study: New Patients Treated With CT-P13 Discontinued Treatment More Often

Biosimilar infliximab, CT-P13, is approved and widely used in a number of regulatory territories. Among those territories is Turkey, where the product is used in treating diseases including rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). A recent population-based study examined the prescribing and utilization of CT-P13 versus the reference infliximab in infliximab-naïve patients and found that discontinuation and switching were more common among patients who began therapy with the biosimilar.

The investigators used the Turkish Ministry of Health database, which includes pharmacy, inpatient, outpatient, and laboratory claims covering approximately 80% of the Turkish population, to identify adult patients with RA or IBD and at least 1 claim for an infliximab product after October 1, 2014, when biosimilar infliximab became available. The 779 patients with RA were followed for 12 months, and the 581 patients with IBD were followed for 6 months.

Among those with RA, 73.8% received the reference and 26.2% received the biosimilar. Mean age was not significantly different between groups, the use of noninfliximab biologics prior to infliximab was similar between groups, and most patients in both cohorts received anti-inflammatory and steroidal drugs. During the follow-up period, there was no significant difference in concomitant drug use.

Patients with RA receiving the reference had a higher average number of infusions (5.3) than those receiving the biosimilar (4.1) and a lower number of vials per infusion (4.9 vs 5.8, respectively). The mean number of days between infusions was shorter among those receiving the reference than the biosimilar (60 days vs 67 days, respectively). Mean time to discontinuation was significantly longer in the reference cohort (263 days) versus the biosimilar cohort (207 days). A total of 27.3% of the reference group discontinued treatment after dose 3, while 45.6% of the biosimilar cohort did the same. Fewer patients taking the reference (23.5%) than the biosimilar (35.8%) switched biologic treatments.

Among those with IBD, 87% received the reference and 13% received CT-P13. The mean age of the patients taking the reference was slightly lower (38 years) than that of those taking the biosimilar (41 years). A lower proportion of the patients in the reference cohort had a codiagnosis of ankylosing spondylitis, psoriasis, or RA (17.3%, 3.4%, and 11.3%, respectively) than in the biosimilar cohort (40.3%, 10.4%, and 19.5%, respectively). Concomitant medication patterns and procedures were similar between the groups.

Those receiving the reference had a higher mean number of infusions (6.5) than the biosimilar cohort (3.8), and a lower number of vials per infusion (4.2 vs 6.1). Mean time between infusions was shorter among those receiving the reference than the biosimilar (52 days vs 63 days, respectively). Mean time to discontinuation was longer in the reference cohort (288 days) than the biosimilar cohort (177 days). A total of 21.8% of the reference group discontinued treatment after dose 3, while 53.2% of the biosimilar cohort did so. Fewer patients taking the reference (14.1%) than the biosimilar (50.6%) switched biologic treatments.

The authors note that a key limitation of the study is a lack of information on reasons for discontinuing or switching. However, they write, “the results of this study demonstrate that medication utilization patterns for CT-P13 are not similar to those for [reference infliximab],” and further studies will be necessary to understand why patients receiving the biosimilar discontinued and switched treatment more often than their peers receiving the reference.

The study’s authors disclose connections with Janssen, maker of the reference infliximab.

Reference

Yazici Y, Xie L, Ogbomo A, et al. A descriptive analysis of real-world treatment patterns of innovator (Remicade) and biosimilar infliximab in an infliximab-naïve Turkish population. Biologics. 2018;12:97-106. doi: 10.2147/BTT.S172241.