Interchangeability, Immunogenecity and Infliximab Biosimilars

A recent study (G Fiorino et al. IBD 2018; 24: 601-6, editorial by KH Katsanos et al 465-6) provides more data on “full interchangeability” in regards to infliximab (IFX) and biosimilars CT-P13 and SB2. Full abstract below.

Key finding in study:

  • Antibodies to infliximab (ATI) cross-reacted with any type of IFX or IFX-biosimilar

Points from the editorial:

  • “The landmark NOR-SWITCH randomized controlled trial showed that 1-time switching from RMC [Remicade] to CT-P13 is not inferior to continued treatment with the infliximab originator…there are no data regarding multiple switches…Consequently, cross-switching (switching between 2 biosimilars), reverse switching (switching from biosimilar to its originator) or multiple/repeated switching is not currently recommended.”
  • This study, however, shows that “if you have already developed antibodies to 1 infliximab product, there is no point in switching to another infliximab product.”


BackgroundInfliximab (IFX) biosimilars CT-P13 and SB2 have comparable efficacy, safety, and immunogenicity to the originator Remicade (RMC). However, concerns about cross-switching patients between the 3 brands were raised in the absence of cross reactivity data between them. We aimed to determine whether antibodies to infliximab (ATI) in inflammatory bowel disease (IBD) patients cross-react with RMC, CT-P13, and SB2.

MethodsBased on previous ATI status, samples from 34 patients participating in the BIOSIM01 study (13 RMC, 9 CT-P13, and 12 switchers) were selected. Patients were treated with either RMC only, or CT-P13 only, or with RMC switched to CT-P13. Additionally, 28 IFX-naïve patients were assayed as controls. In total, 180 samples were analyzed. ATI trough levels were measured in parallel with 3 different bridging Enzyme Linked Immunosorbent Assays constructed using the 3 drugs. Spearman’s coefficient and percentages of agreement were used to study the correlation between each assay.

ResultsIn total, 76 samples out of 152 IFX-treated patient samples were ATI-positive (30 RMC, 14 CT-P13, and 32 switchers). All resulted ATI-positive when either CT-P13 or SB2 bridging assays were used. The overall percentage of agreement was 100% when compared either with CT-P13 or SB2 assays. No significant differences were found among ATI levels and coefficients (Spearman’s 0.98 to 1.0, P < 0.0001).

ConclusionsATI of RMC-treated, CT-P13-treated or RMC to CT-P13 switched patients show full cross-reactivity with CT-P13 and SB2. Findings suggest that immunodominant epitopes in the reference and CT-P13 drugs are equally present in SB2. Data support full interchangeability between biosimilars in regard to immunogenicity.

My take: In patients doing well with IFX, switching to a biosimilar is not currently recommended.  In patients naive to IFX, use of IFX or biosimilar is expected to have similar efficacy.

Related study: B Kang et al. IBD 2018; 24: 607-16.  This prospective study of 36 pediatric patients did not identify any significant differences in efficacy…or immunogenicity after switching from IFX to CT-P13.

Related blog posts:

Biosimilars: “The Horse is Out of the Barn”

A recent study (J Sieczkowska-Golub et al. JPGN 2017; 65: 285-88) reports on 36 pediatric patients who received CT-P13, an infliximab biosimilar.  Key findings:

  • 34 of 36 (94.4%) completed induction therapy
  • Clinical response based on pCDAI was noted in 31 of 36 (86%)
  • Clinical remission based on pCDAI was noted in 24 of 36 (67%)

The authors concluded that the induction was effective and similar to the reference infliximab.

In the accompanying editorial, Dr. de Ridder and Dr. Winter make some crucial observations:

  • “Although the study…is important, the number of subjects in this study are low and follow-up is short (14 weeks).”
  • “It is still a large step from adults to children.” Children may have important differences in IBD pathogenesis and pharmocokinetics may not be the same as in adults.
  • The studies supporting CT-P13 (Planetas, Planetra, and NOR-SWITCH) were studies of adult patients.
  • “The data in children are scarce.” However, “the horse has already left the barn. In many European countries both naive pediatric patients with IBD and patients who have switched from the originator are treated with CT-P13.”
  • While “caution is still needed,” the lower costs of CT-P13 will “lead to wider availability.”

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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Eiffel Tower

Pediatric Views on Biosimilars and Interchangeability

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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Role of Biosimilars in Inflammatory Bowel Disease

A cautionary note on biosimilars has been discussed in a recent review (DT Rubin et al. Gastroenterol & Hepatol 2016; 12: 741-51)

In the recently completed NOR-SWITCH study presented at the United European Gastroenterology Week 2016 meeting, “a total of 481 patients were recruited across 40 centers: all patients had been on stable treatment with the originator infliximab for at least 6 months…When looking specifically at IBD patients, disease worsening was noted in 21.2% of originator infliximab-treated patients and 36.5% of CT-P13-treated Crohn’s disease patients (n=155).”  The 15% difference did not reach statistical significance, but is concerning.  The authors state that “subtle postranslational modifications unique to the biosimilars may be sufficient to lead to antidrug antibody formation with associated loss of response.  Also, it is noted that this study did not include endoscopic evaluation.

The authors note that therapeutic monitoring worked with biosimilar product using available infliximab assays.

My take: We still have a lot to learn.  The preliminary message, until more studies are available, indicate that switching stable patients could increase risk of losing response.

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Puerto Rico

Puerto Rico

Bioequivalence of Biosimilars

From Annals of Internal Medicine: Bioequivalence of Biosimilar TNF-α Inhibitors

Ann Intern Med. Published online August 2016 doi:10.7326/M16-0428


Background: Biosimilars are of growing clinical, regulatory, and commercial importance.

Purpose: To summarize evidence about the bioequivalence between biosimilar and reference tumor necrosis factor-α (TNF-α) inhibitors.

Data Sources: PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and LILACS from inception through 13 April 2016 and, World Health Organization International Clinical Trials Registry Platform, EU Clinical Trials Register, U.S. Food and Drug Administration, and European Medicines Agency from inception through 30 April 2016.

Study Selection: Published English-language studies of any size or design that compared the pharmacokinetics, clinical efficacy, adverse events, or immunogenicity of a biosimilar TNF-α inhibitor with a reference biologic in humans.

Data Extraction: Two reviewers independently screened titles and abstracts, extracted data from selected studies, and assessed study quality.

Data Synthesis: Of 19 eligible studies, 8 were phase 1 randomized trials, 5 were phase 3 randomized trials, and 6 were observational studies. Most phase 1 trials (n = 7) involved healthy volunteers, phase 3 trials involved patients with rheumatoid arthritis, and observational studies involved those with rheumatoid arthritis or inflammatory bowel disease. All phase 1 trials showed that pharmacokinetic parameters of the biosimilar and respective biologic were within the prespecified equivalence margin of 80% to 125%. Phase 3 trials suggested similar clinical responses and adverse events. Adverse events were usually of mild to moderate severity. Two cross-sectional observational studies showed cross-reactivity between products, whereas 4 cohort studies of patients switched from reference to biosimilar products suggested similar efficacy and safety outcomes.

Limitation: Possible publication bias, small sample sizes of many studies, and lack of published studies for several biosimilars.

Conclusion: Preliminary evidence supports the biosimilarity and interchangeability of biosimilar and reference TNF-α inhibitors.

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European Experience with Biosimilars

While there are numerous concerns regarding the use of biosimilar products, the preliminary experience with biosimilar infliximab has been favorable.

Full text link: European Experience of Infliximab Biosimilars for IBD (Gastroenterology & Hepatology)

Key points:

  • Biosimilars are leading to cost reductions of 30-40%.  In addition, to lowering the cost of infliximab, this is leading to reductions in costs for adalimumab and vedolizumab which are competing as 1st line therapies.
  • In the authors study of the first 210 patients, they did not find any difference in terms of immunogenicity or side effects.  In addition, efficacy was comparable to the ‘originator’ drug.

My take: Infliximab and adalimumab have been blockbuster medications for pharmaceutical companies, in part because they provide a great clinical benefit.  However, if biosimilars are truly biosimilar, the cost reductions will result in their widespread adoption.

Related blog post: Biosimilars -Position Statement  GutsandGrowth  This position statement: “Treatment of a child with sustained remission on a specific medication should not be switched to a biosimilar until clinical trials in IBD are available to support the safety and efficacy of such a change”

Castillo San Felipe del Morro

Castillo San Felipe del Morro