To examine the prevalence rates of biosimilar discontinuation and switchback to the originator tumor necrosis factor alpha (TNF) inhibitors following non-medical switch (NMS) in patients.
Real-world studies reporting biosimilar discontinuation and switchback rates following NMS published between January 2012 and August 2018 were identified through a systematic literature review. A meta-analysis estimated the annualized discontinuation and switchback rates. A subsequent meta-analysis assessed annualized incremental discontinuation rate among studies reporting both discontinuation rates in patients who underwent an NMS (switchers) and patients who remained on originators (non-switchers).
A total of 66 publications were identified: 31 in gastroenterology, 32 in rheumatology, and 3 in both. Half of the studies reported switchback rates; only 9 studies reported discontinuation rates for both switchers and non-switchers. Across studies, the mean/range sample size of the NMS patient population was 136/9-1641; mean/range follow-up was 10/3-24 months. Annualized biosimilar discontinuation rate was 21% (95% confidence interval [CI] 18%, 25%). Switchback rate was 14% (95% CI 10%, 17%) among all NMS patients and 62% (95% CI 44%, 80%) among discontinuers. The mean/range sample size of switchers and non-switchers was 344/89-1621 and 768/19-2870, respectively; mean/range follow-up was 11/6-18 and 12/6-8 months, respectively. Annualized incremental biosimilar discontinuation rate was 18% (95% CI 4%, 31%).
Biosimilar discontinuation was found to be prevalent among patients who underwent an NMS from an originator TNF inhibitor to its biosimilar(s) in the real world. In addition, switchback to the originator TNF inhibitors was common following biosimilar discontinuation. Careful consideration is necessary when switching patients already on an originator TNF inhibitor to its biosimilar(s). Main limitations included the heterogeneity of the studies and the limited comparability of the data.