Category Archives: inflammatory bowel disease

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

Testing worm therapy for chronic diarrhea/IBD in Monkeys

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Today’s blog is an excerpt from BBC News (Thanks to Ben Gold for the tip).  The full link:

BBC News – Parasitic worms ‘treat diarrhoea‘

“Chronic diarrhoea could be treated using parasitic worms, a study of monkeys has suggested. Research published in PLOS Pathogens, suggests the treatment restores gut bacteria to a healthy state. Other work in mice has already suggested conditions such as ulcerative colitis could be treated in this way. A UK expert said parasitic worms were being investigated for a range of conditions, including multiple sclerosis and allergies.”

Captivity

“Inflammatory bowel diseases, like colitis, are often fuelled by a wrongly targeted response by the immune system to gut bacteria. Such diseases are more common in developed countries – and scientists suggest this is because people in developing countries have more exposure to parasitic worm (helminth) infections and therefore have a natural protection that has evolved as people and worms learnt to co-exist.


Recent studies have used parasitic worms to successfully treat inflammatory bowel disease in humans, but it is unclear exactly how they do this.

This latest study looked at monkeys because young macaques kept in captivity often develop chronic diarrhoea that can be hard to treat. Five macaques with diarrhoea were treated with parasitic worms called whipworms. Tissue samples were taken before and after treatment and it was found the balance of gut bacteria was restored to required levels. And four out of five animals had less diarrhoea and started to gain weight.

Dr P’ng Loke, of the New York University Langone Medical Center, who led the study, said: ‘The idea for treating colitis with worms is not new, but how this therapy might work remains unclear.  Our findings suggest that exposure to helminths may improve symptoms by restoring the balance to the microbial communities that are attached to the intestinal wall.’

The researchers now plan a study in humans to look at how pig helminth eggs might help alleviate the symptoms of colitis.

Compensating

Prof Graham Rook, of the centre for clinical microbiology at University College London, said a number of research teams were investigating the effects of parasitic worms in various conditions. ‘This is not part of the hygiene hypothesis [which says exposure to bacteria strengthened the immune system]. It’s the “old friends” hypothesis. We co-evolved with these things, so they had to be tolerated. We found ways of suppressing the immune systems, and in some way have come to depend on them.’ And he said the field of research as a whole would be “hugely significant”.  He added: ‘With helminths, if you get the dose right, you can probably live with worms and not have symptoms. But it may well be there is going to be a battery of molecules you could be dosed with to compensate for not meeting our “old friends”.’

THE WONDER OF WORMS

  • Parasitic worms are “old friends” and humans have lived with them for as long as we have existed.
  • And while people in developing countries still do so – and have low levels of inflammatory disease, the opposite is true in developed countries.
  • It appears our immune systems came to rely on parasitic worm infections as part of the way our body defended itself.
  • And when they are no longer there, it appears that may upset our immune systems.
  • Now researchers are looking at how the worms’ effects can be harnessed to treat conditions ranging from multiple sclerosis to allergies.
  • Hookworms and pig whipworms are amongst those being investigated.
  • Results are promising.
  • But those squeamish about dealing with worms or their eggs may not have to worry – it is more likely drugs will be developed that mimic their effects.”

Additional references:

  • -Gastroenterol 2012; 142: 55.  Helminth infection (with enterobiasis) did not reduce risk of IBD in large population-based study (924,000 Danish database).
  • -Gastroenterol 2005; 128: 825. Trichuris suis for UC. 43% improved vs 17% of placebo. Only mildy effective.
  • -Gut 2005; 54: 87-90. Trichuris suis for Crohn’s
  • -Gastroenterol 2005; 129: 768-69. (letter re safety)
  • -NEJM 2010; 363: 1476-78. Interactions between Helminths and immunogenicity.

How new therapies impact colectomy in UC patients

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Has the need for colectomy changed with the increasing use of more potent medical therapies for ulcerative colitis (UC)?  One article gives some insight into this question (Inflamm Bowel Dis 2012; 18: 1641-46).

This French study followed 151 patients with newly diagnosed UC from 2000-2008; median followup was 58 months. During this time, 21 patients (14%) underwent colectomy.  1.3% required colectomy in the first year following diagnosis.

Looking closer at their study, 55% of patients had pancolitis.  Cyclosporin usage, typically given in refractory cases, was the only medication determined to be a predictive factor for surgery.

Medication usage during study period:

  • 68% oral mesalamine products
  • 72% systemic corticosteroids
  • 7% methotrexate
  • 49% azathioprine
  • 9% cyclosporin
  • 30% had received at least one anti-TNF agent

The authors concede several limitations, including the evolving nature of UC treatment.  Yet, they conclude that colectomy still is frequently needed and the use of IBD medications, including anti-TNF, “does not appear to reduce the long-term need for surgery in UC.”

I take issue with the last sentence.  Whether anti-TNF agents prove to be a disease-modifying treatment over the long-term is not known.  In this particular cohort, only 30% were even exposed to these agents.  My conclusion: we need a study designed to answer the question.  This would require larger numbers of patients followed prospectively for many years.

Related blog entries:

Ustekinumab for Crohn’s Disease

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Ustekinumab is emerging as an option for inflammatory bowel disease.  A study examining its effectiveness for TNF-refractory Crohn’s disease has been published (NEJM 2012; 367: 1519-28).

In this trial, members of CERTIFI (Crohn’s Evaluation of Response to Ustekinumab Anti-Interleukin-12/23 for Induction) from 153 centers in 12 countries assessed the efficacy of Ustekinumab in 526 adult patients.  The primary outcome was a clinical response (CDAI >100 point drop) at 6 weeks.

Ustekinumab (currently approved for plaque psoriasis) is a ‘fully human IgG1κ monoclonal antibody’ which blocks the activity of interleukin-12 (IL-12) and interleukin-23 (IL-23) by inhibiting receptors on T cells, natural killer cells, and antigen-presenting cells.  IL-12 and IL-23 have been implicated in the pathophysiology of Crohn’s disease.

This study of ustekinumab was a 36-week randomized, double-blind, placebo-controlled phase 2b trial.  The first 8 weeks were for induction.  After induction, based on response, patients were enrolled in a 28-week maintenance phase.  Initial dosing was 1, 3, or 6 mg/kg of intravenous ustekinumab or placebo.  Maintenance dose was 90 mg subcutaneously.

Patients were permitted to continue receiving stable doses of drugs.  However, entry requirements included a washout period for intravenous glucocorticoids (3 weeks), TNF antagonists (8 weeks), and natalizumab (12 months).

Results:

  • 36.6%, 34.1% and 39.7% of ustekinumab patients (1, 3, and 6 mg/kg respectively) responded at 6 weeks compared with 23.5% of placebo.  The difference was statistically significant for 6 mg/kg/dose.
  • Maintenance therapy (among responders) noted increased clinical remission with ustekinumab compared with placebo 41.7%  vs 27.4%.
  • Overall rates of infection were similar. Serious infections were noted in 6 patients receiving ustekinumab compared with 1 placebo-treated patient.  Infusion reactions were uncommon.
  • Patients who did not have a response to ustekinumab in the induction phase did not benefit from additional ustekinumab in the maintenance phase.

Overall, in this study, patients dosed at 6 mg/kg during induction were more likely to have a response but not more likely to have a remission.  Since all patients in this study had failed at least one TNF antagonist and 50% had failed at least two, the benefit of ustekinumab in other Crohn’s disease patients remains undefined.

Related blog entries:

CHOOSE TNF TRIAL | gutsandgrowth

Vedolizumab -another new IBD treatment | gutsandgrowth

Adding Methotrexate to anti-TNF therapy | gutsandgrowth

More “Survivin” in Crohn’s disease

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Survivin is a member of the inhibitors of apoptosis family.  It helps regulate cell division and prevents cell death.  (Gastroenterology 2012; 143: 1017-26).  While survivin has been shown to be important in cancer, it appears to be important in inflammatory and autoimmune disorders.

In the referenced study, lamina propria T cells (LPT) were isolated from mucosal samples of patients with Crohn’s disease (CD), ulcerative colitis (UC), and controls.  Expression of survivin was assessed by immunohistochemistry, confocal microscopy, and immunoblotting.

LPTs from patients with Crohn’s disease had increased survivin levels; this was not seen in control patients or UC patients.  Furthermore, the investigators showed that the survivin (bound to heat shock protein) was resistant to proteasome degradation.

Implications of this study: 

Survivin may have crucial consequences for CD and other inflammatory/autoimmune diseases; cell proliferation and apoptosis alteration may be important in the pathogenesis of  in these disorders.

Microbiome in pediatric ulcerative colitis

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Alterations in the gastrointestinal tract microbiome may play an important role in many digestive conditions.  A recent article examines microbiome alterations in children with severe ulcerative colitis (UC) (Inflamm Bowel Dis 2012; 18: 1799-1808).

Stool samples from 26 healthy children and 27 children with severe UC were prospectively studied.  After DNA extraction, PCR amplification and microarray hybirdization were performed and analyzed.   None of the patients in the study had received antibiotics or probiotics in the preceding month.

Key findings:

  • There were substantial reductions in “richness,” diversity, and evenness of the gut microbiome in UC patients.  (Richness is a term used to reflect the number of detected phylospecies.)
  • There was a decrease in signal in almost all  phylospecies.
  • The number of phylospecies was reduced in UC (266 ± 69) vs controls (758 ± 3)
  • Steroid responders had even fewer phylospecies compared with responders (142 ± 49  vs. 338 ± 62)

It is not surprising that the stools from these children are much different.  The issues of causation and whether a snapshot of the microbiome diversity will have clinical relevance is not clear.  It is possible that antimicrobials may make an individual more susceptible to inflammatory bowel disease by altering the individual’s microbiome.

Related blog entries:

Eat your veggies…if you don’t want to get sick | gutsandgrowth

Why are we seeing so many more cases | gutsandgrowth

Once daily Mesalamine

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Based on the literature, it is not clear that there is any need to give melamine more than once a day; this is often in contrast to labeling for many of these products:

  1. Inflamm Bowel Dis 2012; 18: 1785-94 
  2. Inflamm Bowel Dis 2012; 18: 1885-93

The 1st study identified 11 relevant randomized studies, after excluding 6870 that were considered irrelevant. Five of these studies were single blind and one was open-label; the remainder were double-blind randomized trials. In total, these studies examined 4070 patients.

Mesalamine products studied: Mesalazine (Salofalk), MMX mesalamine, Asacol, and Pentasa

Summary of findings:

  • Failure to induce clinical remission: relative risk (RR) with once daily 0.95; absolute risk 421 per 1000 in once daily group
  • Failure to induce clinical improvement: RR 0.87; absolute risk 398 per 1000
  • Failure to maintain clinical remission at 12 months: RR 0.92; absolute risk 286 per 1000
  • Failure to adhere to study medication regimen: RR 1.21; absolute risk 128 per 1000

Thus, this meta-analysis indicates that once daily dosing is as effective as conventional dosing for both induction and maintenance, at least with the formulations that were tested. Also, in this meta-analysis, adherence was not improved with once daily therapy, though some previous studies have indicated that once daily therapy may be helpful particularly in the first few months of treatment.

The 2nd study examined 213 patients for maintenance of UC remission; patients were randomized to receive either Asacol 2.4 g once a day (QD) or 800 mg three times a day (TID). Patients were treated at 32 UK centers and had an average age of 50 years. Relapse rates were 31% for QD therapy and 45% for TID over 1 year.  This study showed that QD was noninferior to TID and possibly superior, perhaps due to improved adherence.

Perhaps it is time to give all mesalamine products once a day.

Screening for subclinical PSC in IBD?

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In children with IBD, elevated liver enzymes raise the concern for primary sclerosing cholangitis (PSC).  PSC is thought to develop in up to 5% of patients with IBD.  To look more closely at this issue, a group of investigators examined 73 children (median age 12 years) with IBD with MRCP to look for evidence of PSC (JPGN 2012; 55: 308-13).

The majority of these patients had an MRCP at the time of an MRE; this was ordered independently from specific laboratory or clinical factors.  On average, the date for MRCP was about one year after the date of diagnosis.  In this group, 49 (67%) had Crohn’s disease (CD), 19 (26%) had indeterminate colitis (IC), and 5 (6.8%) had ulcerative colitis (UC) [In the results section, the authors state a discrepancy from previous: 47 with CD, 18 with IC, and 8 with UC.]

11 (15%) children had PSC-type lesions identified by MRCP.  6 of these patients had CD, 3 had IC, and 2 had UC.  Among the PSC group, 5 had abnormal AST & ALT, 4 had abnormal GGT, and 1 had abnormal bilirubin at time of diagnosis & similar numbers were present at the time of MRCP.  A much lower percentage of the non-PSC group (n=62), had abnormal LFTs.  Though, at time of MRCP, 9 (14.5%) had abnormal ALT.

An editorial in the same issue (page 238), concludes that “screening for PSC by MRCP in all of the newly diagnosed patients with IBD seems promising.”  Really?  Given a lack of therapeutic options, I don’t think identifying preclinical PSC makes any sense.  An exception would be in patients with persistent liver test abnormalities to avoid attributing this to medication toxicity.

Previous RELATED BLOG ENTRies

Challenges with primary sclerosing cholangitis | gutsandgrowth

Colonic disease and PSC | gutsandgrowth

Additional reference:

-Hepatology 2009; 50: 808-14.  High-dose ursodeoxycholic acid not effective for PSC (worsened outcomes noted)

According to the study which you would never qualify for…

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When I give patients advice on treatment, I rely on well-designed studies to help select the medications/treatments that are most likely to be effective.  It is interesting to ponder how applicable these studies are and how closely they reflect the patient population that I’m seeing.  A recent article indicates that in a tertiary referral center for inflammatory bowel disease, the majority of patients would be excluded from participation in these studies (Clin Gastroenterol Hepatol 2012; 10: 1002-07).

These authors performed a retrospective cohort study of patients presenting to the Mount Sinai Medical Center between January 2008 and June 2009.  For Crohn’s disease (CD) patients, the authors selected 7 published randomized control trials of biological therapy for patients with moderate-severe disease (ACCENT 1, CLASSIC 1, CHARM, PRECISE 1, ENCORE, ENACT, and SONIC).  For Ulcerative Colitis (UC), they selected ACT 1 and ACT 2 trials for moderate-severe UC.

Only 31.1% of 206 patients with IBD would have been eligible to participate in any of the selected RCTs.  The average age of their patients was about 35 and did not differ significantly among patients who would qualify compared to those who would not.

Among the CD patients, the inflammatory phenotype was most likely to qualify; 37 patients with inflammatory disease behavior would have been eligible.  While only 54% (37 of 68) of the inflammatory phenotype would have qualified, this accounted for 86% of the total population who would have qualified (only 34% of the entire CD cohort would have been eligible for study participation).

Among the UC patients, there were no disease characteristics or demographics associated with eligibility; that is, there was a similar distribution of disease extents, Mayo scores, disease duration, gender, and age among the patients who qualified and those who did not.

Reasons for exclusion: stricturing or penetrating disease, steroid dosing, comorbities, concomitant therapies, or prior exposure to biologics.

The authors note that the results from this study mirror that from similar studies with other chronic diseases including rheumatoid arthritis, chronic obstructive pulmonary diseases, and congestive heart failure.

When the authors looked at the trial-ineligible patients, 60% had a response to biological therapy. The response rates for ineligible patients (compared to eligible patients) were lower for CD patients but not for UC patients (Figure 2 in study).

While stringent criteria for eligibility limit the external validity of the study results, these criteria are in place for multiple reasons.  Less rigid selection criteria would require larger study populations, longer duration studies, and greater costs.

The issue of study applicability is even a bigger problem in pediatrics.  This is primarily due to fewer high quality studies in children. As such, many clinical judgements require extrapolation from adult studies.

Related blog post:

Interpreting industry-funded studies

What is the risk of colon cancer in IBD?

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Some recent studies have shown that colorectal cancer complicating IBD may not be as common as previously thought or may be decreasing in incidence (Gastroenterology 2012; 143: 375-81 & Gastroenterology 2012; 143: 382-89 ).

The first study used a nationwide cohort of 47,374 Danish patients with IBD over a 30-year period.  During a 178 million person-years of follow-up evaluation, 268 patients with ulcerative colitis (UC) and 70 patients with Crohn’s disease (CD) developed colorectal cancer (CRC).  The risk was comparable to the general population (RR 1.07)!  Furthermore, the relative risk for CRC decreased over sequential time periods: 1.34  (1979-88) to 0.57 (1999-2008).

Increased risk:

  • UC diagnosed in childhood or adolescence
  • longer disease duration
  • patients with primary sclerosing cholangitis

Their conclusion, ‘the overall risk of CRC in patients with UC has decreased markedly over time and no longer exceeds that of the general population, at least in the first decade after diagnosis.”  And, based on their data, patients with Crohn’s disease are not at increased risk for CRC.

The second study from California used a large Kaiser Permanente database from 1998-June 2010.  29 cancers were identified in CD (n=5603) and 53 in UC (n=10,895) patients.  The incidence per 100,000 for CRC was 75 for CD, 76 for UC, and 47 for general population.

These authors conclude that there is an increased risk of CRC in a community-based IBD population between 1998-2010 despite advances in medical treatment.

To understand the discrepancy of these reports, the same issue provides an editorial (page 288).  My take is that the current incidence of CRC is lower than in previous reports but that the risk factors identified in the Danish cohort (see above) likely remain important.

Additional references:

  • -Gastroenterol 2009; 136: 718. 22% of cancers occurred before recommended surveillance in adults (only 9% if exclusion of patients who had IBD and cancers diagnosed at same time).
  • Colon Cancer Survival Calculator http://www.mayoclinic.com/calcs-Gastro 2010; 138: 207-2177 (entire issue)
  • -JAMA 2009; 302: 649. Aspirin use likely increases survival after dx of colon cancer. Commentary-Gastro 2010;138: 2012.
  • -NEJM 2009; 361: 2449. molecular basis of colorectal cancer
  • -Gut 2008; 57: 1246. IBD and colon cancer
  • -IBD 2007; 4: 367. 5ASA Rx did not reduce rate of cancer in large study of UC/CD -review of 18,000 colorectal cancer cases. IBD increased risk of CRC 6-7-fold..
  • -Clin Gastro & Hep 2006; 4: 1346. aminosalicylates reduce CRC.
  • -Gastroenterol 2006; 130: 1030, 1039, 1350. 600 patients followed for 35 yrs: CRC by colitis duration: 2.5% @ 20yrs, 7.6% @ 30yrs, 10.8% @ 40yrs. 5 year survival was 73% among those with cancer. 2nd study showed main CRC risk in UC pts is among those with extensive colitis.
  • -Clin Gastro & Hepatol 2004; 2: 1088. Lower cancer risk in this cohort, n=1460. CRC 0.4 @10yrs, 1.1% @ 20yrs, 2.1% @ 30yrs. Lower CRC may be due to more surgery in Rx failures & use of 5-ASA.
  • -Clinical perspectives in Gastro 1999; 2: 9 & 25. (review) surveillance/ overview take 4 bx q10cm. start p 8yrs in pancolitis & 15yrs for left-sided dz. Cancer risk: ~5% at 20yrs + 1%/yr p 20yrs in pancolitis.
  • -Gastroenterol 2003; 125: 1311. Advancement of dysplasia to cancer in UC.