A recent commmentary (D Patel, KT Park. JPGN 2017; 134-6) explains the topic of interchangeability and its relationship to biosimlars. While biosimilars are expected to reduce the cost of biologic therapy, there are concerns regarding immunogenicity and whether switching to these products could reduce therapeutic sustainability.
The authors explain that some products are truly interchangeable and produce the same clinical result. An interchangeable medicine (eg. typical generic) does not increase safety risk and switching from originator drug can be done by pharmacists or government payers without intervention of the prescribing health provider.
CT-P13 (Inflectra) has been approved as a biosimilar but has not been deemed an interchangeable product. This is important. Biosimilars “could have clinical consequences and repeated switches may increase immunogenicity.” Also, biosimilar products are much more complicated products than typical generic drugs.
Other key points:
- The assumption that CT-P13 is interchangeable in pediatric IBD is “highly debatable.” Biosimilars undergo fewer studies than originator products. CT-P13 has data from PLANETRA and PLANETAS trials “which may not be applicable for IBD, particularly pediatric IBD, given the inherent differences in disease pathophysiology.”
- “No long-term, multiple-switch (eg. originator to biosimilar to originator) studies in pediatric or adult patients have been performed.”
- “It is premature and possibly risky to assume that interchangeability will not cause differences in immunogenicity without long-term evidence in the pediatric population.” Pediatric patients likely have a “higher probability of developing autoantiantibodies” and need effective therapy for a longer duration.
My take: We still have a lot to learn. Until more studies are available, switching stable patients could increase risk of losing response.
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