Tag Archives: antibodies to infliximab

Short Takes on IBD Articles

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Singh S, et al. Gastroenterol 2015; 148: 64-76.  In this study, the authors identified 21 trials with 2006 participants to examine the comparative efficacy of pharmacologic interventions to prevent relapse of Crohn’s disease (CD) after surgery.  Conclusion: “anti-TNF monotherapy appears to be the most effective strategy for postoperative prophylaxis for CD.” The relative risk of clinical relapse and endoscopic relapse with anti-TNF monotherapy was estimated to be between 0.02-0.20 and 0.005-0.04, respectively. Thus, those at highest risk for recurrence, including younger individuals, smokers, penetrating CD, perianal CD, and recurrent surgeries) are most likely to benefit.(Related blog post: More Lessons in TNF Therapy (Part 1) | gutsandgrowth)

Pariente B, et al. Gastroenterol 2015; 148: 52-63. The researchers in this cross-sectional study developed the Lémann Index which measures cumulative structural bowel damage in patients with CD.  My only complaint with this study was the associated editorial on pages 8-10, titled “The Holy Grail, or Only Half Way There?”  There are too many medical advances compared to ‘the holy grail’ and, in my opinion, this shouldn’t be one of them.

Zitomersky NL et al. Inflamm Bowel Dis 2015; 21: 307-14.  In this study the authors examine the relationship between the development of antibodies to infliximab (ATI) and the risk of surgery in a cross-sectional cohort of pediatric and young adult patients.  Not surprisingly, development of ATI, which was noted in 20% of cohort, correlated with reductions in infliximab levels and higher risk of surgery.  Interestingly, prior (but not current) immunomodulator therapy was associated with lower antibody levels (P=0.007).  Perhaps, “step-up” therapy may lower the risk of ATI. (This was a point noted by James Markowitz in a previous post: More NASPGHAN Meeting Notes: IBD Hot Topics | gutsandgrowth)

Rogler G, Vavricka S. Inflamm Bowel Dis 2015; 21: 400-08. This review article discusses the exposome in IBD.  Exposures include air pollution, diet, drugs, infections, water pollution, food additives, and smoking.  These exposures influence the gut microbiome and genetic susceptibility. “Only environmental influences…explain the rising incidence in IBD worldwide. The investigation of the exposome…is an enormous challenge…[but] of crucial importance.” (Related blog post: What do you know about the “exposome”? | gutsandgrowth)

Kalmon RS. Inflamm Bowel Dis 2015; 21: 428-35. Review article provides information when there is a prior personal or family history of malignancy (=avoid thiopurines).  Figure 2 is a suggested algorithm for those with IBD and a previous diagnosis of cancer.

  • In those in which the cancer is adequately controlled, the recommendations indicate that if it has been more than 2 years since completion of therapy to use a ‘step-up’ management and favor methotrexate over thiopurines
  • In those with less than 2 years since completion of cancer treatment and not responsive to 5-ASAs/antibiotics, then “consider monotherapy with biologic agents.”
  • In those still receiving chemotherapy, the authors suggest “hold immunosuppression and follow course of IBD.  If IBD not well controlled despite chemotherapy, 5-ASAs and antibiotics, treat flares with steroids, then consider biologic agents.”

More Lessons in TNF Therapy (Part 2)

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Another useful study (Clin Gastroenterol Hepatol 2014; 12: 1474-81, editorial 1482-84 [podcast available: http://www.gastro.org/cghpodcast%5D) on infliximab (IFX) usage addresses the issue of reinitiating IFX therapy after a “drug holiday.”

The authors conducted their retrospective single-center study in Belgium.  This detail is important as interruption of therapy is more common in Europe where agents like IFX are often stopped when patients are doing well.  In the U.S. stopping IFX occurs more commonly when there are antibodies to infliximab (ATIs) or increased clinical symptoms.  In this particularly study, 22% were restarted on IFX after loss of response (despite dose optimization) and the remainder had been stopped either due to remission, pregnancy or patient decision. Also, in their center, patients do not receive IFX unless they were allergic or refractory to steroids and/or immunomodulators for a minimum of 3 months.

In total there were 128 patients (105 with Crohn’s and 23 with ulcerative colitis).

Key findings:

  • Reintroduction of IFX resulted in a clinical response in 84.5% at week 14, 70% at 1 year, and 61% at more than 4 years.
  • Higher response was noted in those who discontinued because of remission: 90% at week 14, 77.5% at 1 year, and 66.6% at more than 4 years.
  • In patients with prior loss of response, 45% had response to reintroduction of IFX at 1 year.
  • 15 patients had acute infusion reactions, seven of these were severe.
  • ATI-positivity was associated with a higher risk of infusion reaction, though most ATI-positive patients did not develop a reaction.  Particularly in ATI-positive patients, the editorial recommends a “slow infusion protocol and possibly steroids before administration of the drug.”
  • The editorial states: “it seems reasonable to check drug levels and antibodies before the second infliximab dose.” Trough levels >2 mcg/mL and undetectable ATIs early after restarting the drug were associated with good responses. “For patients with high ATIs (≥9.1 U/mL), another drug should be considered.”
  • Among those with detectable ATIs, response at 1 year was noted in 54.8%.
  • Immunomodulator cotherapy had a beneficial effect.

Bottomline: This study provides useful insights for patients who need to reinitiate IFX treatment.  In addition, some IFX failures may be able to resume IFX after a drug holiday.

Related blog posts:

What you might not know about anti-TNF monitoring…

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At a recent group dinner meeting, we had the opportunity to review therapeutic anti-TNF monitoring. In addition, we discussed emerging treatments for inflammatory bowel disease, like golimumab, tofacintinib and vedolizumab.

As noted in previous blog entries (see below), therapeutic anti-TNF monitoring can help adjust treatment.  Namely, if a patient loses response to therapy and has low trough levels of anti-TNF (Infliximab ❤ μg/mL, Adalimumab <8 μg/mL, or certolizumab <27.5 μg/mL) without antidrug antibodies (ADAs), then increasing the dose is likely to be effective.  However, if a patient has a therapeutic level and is not responding, changing to another agent and/or further investigation is worthwhile.

So, what information is new?

  • Only about 20% of patients who lose clinical response develop ADAs.  So, drug level, rather than ADAs, is most helpful.
  • For infliximab, adjusting dose 14 weeks into therapy to achieve a target trough level between 3-7 mcg/mL may be helpful.
  • Severe colitis patients may need higher initial doses (?as high as 20 mg/kg) due to potential for ‘antigen sink.’  This is due to notably higher clearance in the presence of low albumin, and high CRP.  Other factors that increase clearance include higher BMI and male gender.
  • About 1/2 of patients who receive higher doses due to severe disease may be able to deescalate dosage when improved. (?which half)
  • Currently, a reactive approach to checking levels is common in U.S. in part due to costs associated with checking trough levels and ADAs (as much as $2500).  That is, most commonly checking levels is undertaken in patients with suboptimal clinical response.  A proactive approach to achieve target levels may be shown to be helpful.
  • While studies have not shown higher adverse reactions with higher trough levels, there are a few clinical situations in which lower trough levels can be important.  In patients with psoriatic skin lesions and arthralgias, if trough levels are elevated, lowering the dose may be helpful.

Outstanding questions?

  • Should patients have drug levels checked when they are asymptomatic?
  • How does a practitioner account for variability among different laboratory assays?
  • What is the optimal target level for each anti-TNF agent? Is this different in Crohn disease compared with ulcerative colitis? Is the trough target level different in adults than children?
  • Is there a toxic level?
  • If a rapid test response were available, would checking drug levels be needed for hospitalized patients to assess anti-TNF rescue therapy?

Related blog links:

Disclaimer: These blog posts are for educational purposes only. Specific dosing 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

Monitoring TNF antagonists in inflammatory bowel disease

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Previously, this blog has discussed the use of drug monitoring in inflammatory bowel disease (Drug levels for inflammatory bowel disease | gutsandgrowth).  A good review of this topic has been published recently (Clin Gastroenterol Hepatol 2012; 10: 1079-87).

Some of the useful pointers:

  • Factors that influence clearance of TNF antagonists are reviewed:
  1. Antidrug antibodies (ADA) increase clearance and worsen outcomes
  2. Use of concomitant immunosuppressives reduces the likelihood of ADA formation and increase drug concentration.   In the SONIC trial, use of azathioprine was associated with trough infliximab (IFX) levels of 3.5 μg/mL compared with 1.6 μg/mL with monotherapy.  Also, ADA was reduce: 0.9% compared with 14.6% in the monotherapy group. [Other studies though have found variable effects of cotherapy.]
  3. Low serum albumin and high CRP are associated with increased drug clearance
  4. Individuals with high body size and males are more likely to have increased drug clearance.
  • Better assays for measurement of IFX and adalimumab (ADL) are now available.
  • Currently a trial evaluating trough levels is underway: Trough Level Adapted Infliximab Treatment (TAXIT).  With this study, the accepted target range for trough levels is 3-7 μg/mL.  Levels >7 μg/mL are considered supratherapeutic and allows for a prolongation of dosing interval.  Preliminary data confirm that trough levels inversely correlate with CRP.
  • Proposed algorithm in individuals with loss of response & positive ADA.  If ADAs present at high titer, then switch to different TNF antagonist.  If low  titer, could either switch or attempt drug escalation.
  • With IFX, when antibodies to infliximab (ATIs) are present, the likelihood of responding to increased dose is less than 20% whereas changing to different TNF antagonist has about an 90% response (in patients who were previous responders).
  • Proposed algorithm in individuals with loss of response & negative ADA.  If subtherapeutic trough levels (IFX ❤ μg/mL, ADL <8 μg/mL, or certolizumab <27.5 μg/mL), then dose escalation is worthwhile.  If drug levels are therapeutic, then dose escalation will not be effective.
  • With IFX, more than 85% of patients will respond to drug escalation when the trough level is subtherapeutic. This is much more favorable than switching agents.
  • One other issue with ADAs is that they may be transient is some patients.  Perhaps one-fourth of ATIs may be transient which may explain why some individuals with ATIs may still respond to dose escalation.

These points give several reasons why drug monitoring is useful in individuals with loss of response and may help determine whether patients responding to therapy may be able to prolong dose intervals.  At the same time, when an individual is not responding to therapy, it is also important to determine if in fact active inflammation is present with objective markers and to consider alternative explanations for GI symptoms (eg. Clostridium difficile infection, irritable bowel, bacterial overgrowth, etc.).

Related blog entries:

Only one chance to make first impression | gutsandgrowth

When nothing else is working | gutsandgrowth

Infliximab for children with Ulcerative Colitis | gutsandgrowth

Adalimumab for children with Crohn’s disease | gutsandgrowth

CHOOSE TNF TRIAL | gutsandgrowth