Tag Archives: infliximab

Pediatric Views on Biosimilars and Interchangeability

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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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Good Safety Data on Infliximab vis a vis Malignancy and Hemophagocytic Lymphohistiocytosis

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Using data from 5766 pediatric participants with inflammatory bowel disease in a prospective DEVELOP study (JS Hyams, MC Dubinsky et al. Gastroenterol 2017; 152: 1901-14) provide more reassurance regarding the safety of infliximab.  This study took place between 2007 to 2016 and accounted for 24,543 patient-years of followup.  While the study examined rates of malignancy, the SEER database does not include non-melanoma skin cancer; thus, the authors did not have a suitable comparator for this outcome; there were two cases of basal cell carcinoma in the study population.  This article’s abstract was published on this blog previously: Infliximab Not Associated with Malignancy

Key findings:

  • There was NO increased risk of malignancy or hemophagocytic lymphohistiocytosis (HLH) in patients exposed to infliximab as monotherapy.
  • Malignancy risk was 0.46 per 1000 patient-years in patients with infliximab exposure compared with 1.12/1000 patient-years in patients who had no exposure to biologics.
  • HLH risk was 0 in those with infliximab monotherapy compared with 0.56 per 1000 patient-years in those who had no exposure to biologics.
  • Patients exposed to thiopurines with or without biologics did have increased risks of malignancy compared with comparative populations. 13 of 15 patients who developed a malignancy and all 5 patients who developed HLH had thiopurine exposure.
  • Thiopurine exposed patients had 0.75 malignancy events per 1000 patient-years compared to 0.27 malignancy events per 1000 patient-years for patients who had no thiopurine exposure
  • Thiopurine exposed patients had 0.29 HLH events per 1000 patient-years compared to 0 HLH events per 1000 patient-years for patients who had no thiopurine exposure
  • In their discussion, the authors note that after discontinuation of thiopurine therapy for 1 or more years, the standardized incidence ratio (SIR) for malignancy approached the non-exposed group (1.48 compared to 1.30); whereas ongoing or recent thiopurine exposure had SIR of 4.45.

Limitations: Study duration (<10 years). Hard to detect changes in rare malignancies

My take: In this largest prospective pediatric cohort to date, there is NO increased risk of malignancy (excluding non-melanoma skin cancer) or HLH with infliximab therapy; however, there is a trend towards increased risk among those with thiopurine exposure. Nevertheless, as malignancy is a rare event, very low increased risk of malignancy with infliximab cannot be entirely excluded.

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For HLH:

 

Adalimumab Can Reverse Growth Failure in Pediatric Crohn’s Disease

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In an industry-sponsored study (TD Walters et al. Inflamm Bowel Dis 2017; 23: 967-75), adalimumab (ADA) was shown to be effective agent in reversing growth failure associated with pediatric Crohn’s disease (CD).

Background:  About one-third of children and adolescents with CD suffer from growth failure and delayed puberty.  Several prior studies have shown that anti-TNF therapy can improve height velocity and that early treatment with anti-TNF therapy (≤3 months after diagnosis) leads to greater improvement in height obtained, if initiated before puberty or early into puberty. This study examines the effectiveness of ADA in children from the IMAgINE 1 trial.

The authors identified 73 participants with growth delays (& adequate data) along with 27 participants with no growth delays.

Key findings:

  • ADA therapy significantly improved and normalized growth rates at 26 and 52 weeks in patients with baseline linear growth impairment.
  • At week 26, height velocity z-score was 1.33 among 23 children in remission compared with -0.78 (n=29) among “nonremitters”
  • At week 52, height velocity z-score was 2.17 among 27 children in remission compared with -1.57 (n=17) among “nonremitters”

My take: In moderate to severe CD, anti-TNF agents have been demonstrated to reverse growth failure; though, this is expected to occur only in patients with clinical response. To my knowledge, no other CD medical therapies have been proven to reverse growth failure (surgical treatment can improve growth as well).

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Hepatitis B Reactivation Due to Immunosuppressive Therapies

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The topic of Hepatitis B virus (HBV) reactivation has been discussed on this blog before (see link below).  Another excellent review on this topic (R Lomba, TJ Liang. Gastroenterol 2017; 152: 1297-1309) has been published.  The authors examine the course and mechanisms of HBV reactivation.  They divide the risk of reactivation into three groups: high, moderate and low risk and proposed management.

High risk groups, which have >10% risk of reactivation) include the following

  • B-cell-depleting agents including rituximab, ofatumumab, alemtuumab, and ibritumumab
  • High-dose corticosteroids (>20 mg/day in adults)
  • Antracyclines including doxorubicin
  • Potent TNF-α inhibitors: infliximab, adalimummab, certolizumab, and golimumab
  • Local therapy ofr HCC including TACE (transarterial chemoembolization)

Moderate groups (1-10% reactivation) include cytokine-based Rx (eg. abatacept, ustekinumab, natalizumab, vedolizumab), cyclosporine, systemic chemotherapy, moderate corticosteroid dosing

Low risk groups (<1% reactivation) include thiopurines (azathioprine, 6-mercaptopurine), and methotrexate as well as short-term low-dose corticosteroids.

Management:

  • For HBV screening, the authors recommend HBsAg and anti-HBc testing
  • Prophylactic therapy with potent oral anti-HBV therapies are recommended for those at moderate or high risk of reactivation.  In those at low risk, the options include prophylactic treatment or watchful monitoring.
  • A more detailed algorithm is provided in Figure 3.  In those with HBsAg positivity, if HBV DNA is less than 2000 U/mL, this algorithm suggests monitoring labs (HBsAg, ALT, HBV DNA every 3 months)

Mechanisms of HBV reactivation are discussed.  For example, with TNF-α inhibitors “can activate a unique host antiviral pathway, the APOBEC (apolipoprotein B mRNA editing enzyme, catlytic polypeptide-like) proteins, that cause the degradation of cccDNA in HBV-infected cells. Thus, blocking this endogenous antiviral pathway may lead to a higher HBV replication state and HBV reactivation.”

My take: In pediatric gastroenterology, we do not see a lot of HBV reactivation. Nevertheless, we do use many of the medications which can trigger HBV reactivation and need to keep these recommendations in mind.

Related blog post: What HBV Testing is Needed Before TNF Inhibitor Therapy

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Surgical Reset for Anti-TNF Therapy with Crohn’s Disease

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A recent study (A Assa et al. Inflamm Bowel Dis 2017; 23: 791-97) indicates that after surgery, anti-TNFα treatment is worth another try.

In this retrospective study with 53 children, 18 had “pharmacodynamic failure” with anti-TNFα medications (PK group) and 35 were controls. “Phamacocynamic failure is characterized by either a lack of improvement of CD symptoms or  loss of response after initial improvement in the setting of adequate serum drug levels without ADAs” [antidrug antibodies].

Key findings:

  • Mean age at time of intestinal resection was 14.8 years
  • Median time from resection to anti-TNF initiation was 8 months
  • Compared to the control group, the PK group had similar response to anti-TNF therapy.   “Similar proportions of patients from both groups were in clinical remission on anti-TNF treatment after 12 months and at the end of follow-up (1.8 years)”
  • At 12 months, remission rates were 89% (PK) versus 88.5% (control)

The authors propose an explanation: “A plausible explanation for this finding is that in severely inflamed tissue with high inflammatory burden, local high levels of TNFα serves as a sink for anti-TNFα antibodies and that tissue injury and local hypoxia might further limit drug penetrance to its target.”

My take: This information is useful.  Many patients who have surgery may respond to anti-TNFα therapy subsequently.  The unanswered question: Could more frequent dosing of anti-TNFα therapy have averted surgery in some patients by overcoming areas of intense disease?

 

Infliximab Not Associated with Malignancy

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JS Hyams et al. Gastroenterology http://dx.doi.org/10.1053/j.gastro.2017.02.004

Using the DEVELOP registry, a prospective study showed no increased risk of malignancy among 5766 pediatric participants with inflammatory bowel disease.

Link: Full Abstract

Immunosuppressive therapy for inflammatory bowel disease (IBD) in pediatric patients is thought to increase risk of malignancy and lymphoproliferative disorders, including hemophagocytic lymphohistiocytosis (HLH). We compared unadjusted incidence rates and of malignancy and HLH in pediatric patients with IBD exposed to infliximab compared with patients not exposed to biologics and calculated standardized incidence ratios (SIRs).

Methods

We collected and analyzed data from 5766 participants in a prospective study of long-term outcomes of pediatric patients with IBD (NCT00606346), from 2007 through 30 June 2016. Patients were 17 years old or younger and had Crohn’s disease, ulcerative colitis, or IBD unclassified with 24,543.0 patient-years of follow-up. We estimated incidence rates for malignancy and HLH as events/1000 patient-years of follow-up. We calculated age-, sex-, and race-adjusted SIRs, with 95% CIs, using the Surveillance, Epidemiology, and End Results Program (SEER) database.

Results

Thirteen of the 15 patients who developed a malignancy and all 5 of the patients who developed HLH had been exposed to thiopurine; 10 patients with malignancy patients had also been exposed to a biologic agent. Unadjusted incidence rates showed no increased risk of malignancy (0.46/1000 patient-years) or HLH (0.0/1000 patient-years) in patients exposed to infliximab as the only biologic vs those unexposed to biologics (malignancy: 1.12/1000 patient-years; HLH: 0.56/1000 patient-years). SIRs did not demonstrate an increased risk of malignancy among patients exposed to infliximab (SIR; 1.69; 95% CI, 0.46–4.32) vs patients not exposed to a biologic agent (SIR, 2.17; 95% CI, 0.59–5.56), even when patients were stratified by thiopurine exposure.

Conclusions

In determination of age-, sex- and race-adjusted SIRs using data from a large clinical trial and the SEER database, we found that infliximab exposure did not associate with increased risk of malignancy or HLH in pediatric patients with IBD. Thiopurine exposure is an important precedent event for the development of malignancy or HLH in pediatric patients with IBD.

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Rare Tragic Reaction to Infliximab

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A recent post on the pediatric GI Listserv pointed out a troubling case report: “Fatal Central Nervous System Disease Following First Infliximab Infusion in a Child With Inflammatory Bowel Disease,” FM. Baumer et al; Pediatric Neurology 2016; 57: 91-94.

“A seven-year-old boy diagnosed with ulcerative colitis and primary sclerosing cholangitis received infliximab. Six hours following his uneventful infusion, he awoke with headache and emesis and rapidly became obtunded…Cranial computed tomography revealed hypodense lesions in the cerebral hemispheres, cerebellum, and pons accompanied by hemorrhage…Within four days he met criteria for brain death.”

The authors note that “the close temporal association between our patient’s presentation and the infliximab infusion raises concern for a drug-related cause for his cerebral injury.” While this case report is terribly sad, severe and fatal reactions can unfortunately be encountered with a wide range of medications, including commonly used antibiotics.

My take: Thus, while the vast majority of pediatric patients with inflammatory bowel disease will benefit from infliximab therapy, there are rare tragic outcomes.  img_3954

 

Support for Step-Up Therapy and Thiopurines

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A retrospective study (H Bar-Yoseph et al. Clin Gastroenterol Hepatol 2017; 15: 69-75) indicated that thiopurine use before infliximab (IFX) was associated with the prevention of antidrug antibody formation in patients with Crohn’s disease.

The authors had 207 eligible patients which included 93 who received IFX monotherapy, 52 who received combination therapy after response to thiopurine, 34 who received IFX after lack of response to thiopurines (but continued with combination treatment), and 28 who received de novo combination therapy.  The total number of patients followed in these centers is much higher, but they excluded those with episodic infusions and for other reasons that could affect their conclusions.

Key findings:

  • Prior thiopurine therapy was associated with lower antidrug antibodies (ADA). At 1 year, past thiopurine responders had 19.3% ADA, past thiopurine failures had 16.1% ADA; both were much lower that the monotherapy rate of 46.6%  The de novo combination group had a rate of 21.9% which did not reach significance.
  • Interestingly, after the first 5 months, the de novo combination group did not develop further ADA but during the first 5 months the rate of ADA was quite similar to the monotherapy rate. This could be related to the notion that thiopurines may take 3-6 months to achieve full effect.
  • Combination therapy (compiled)  was associated with higher rates of clinical remission (58.8% vs 40.9%) and lower rates of active disease (8.8% vs. 21.5%).

Overall, this study showed high rates of ADA compared to many studies but the conclusions are similar to other published studies.  It could be that many of those with positive ADA were lower antibody levels and that many of these levels may not be clinically significant. The study has limitations mainly related to being a retrospective study.

My take: This study supports the following:

  1. Combination therapy is more effective than monotherapy
  2. Using an immunomodulator before starting infliximab may reduce ADA formation more effectively than starting combination therapy de novo.

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Disclaimer: These blog posts are for educational purposes only. Specific dosing/usage of medications (along with potential adverse effects) should be confirmed by prescribing physician.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

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Role of Biosimilars in Inflammatory Bowel Disease

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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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