Microparticles and Pediatric IBD

Before reading a recent publication (JPGN 2013; 56: 401-07), I was not aware of microparticles; microparticles may play an important role in the development of venous thromboembolism (VTE).  Pediatric patients with inflammatory bowel disease (IBD) have a higher relative risk of VTE compared to their peers than individuals >60 years of age, though the absolute risk is low.  Much of the pathophysiology underlying the increased VTE risk remain uncertain.

Microparticles have been called “platelet dust” and are microvesicles that are released from the plasma membrane of many cells (leukocytes, red blood cells, endothelial cells, and platelets).

This study examined plasma samples from 33 pediatric patients with Crohn disease (CD), 20 pediatric patients with ulcerative colitis (UC), and 60 healthy controls. Subsequently, microparticles’ procoagulant activity was measured.  The CD and UC patients were consecutively enrolled from the outpatient clinic.  Only 3 patients in each IBD group was receiving a biologic therapy (infliximab). The disease activity and extent were compared with measures of procoagulant activity.

Several assays were undertaken to assess microparticles and thrombin generation. Key findings:

  • Increased procoagulant function of microparticles was identified in all CD patients (active and quiescent) and in UC patients with active disease.
  • A positive correlation was found between disease activity scores and procoagulant activity.

The authors note that elevated microparticles “may play a role in inflammation.” Inflammation and coagulation likely influence each other.  The authors note that VTE risk is greatest during flares but is still increased in patients in remission compared with controls.

The authors do not discuss the relationship of mucosal healing to microparticles or VTE. However, given that clinical remission is not defined currently based on mucosal healing, it would be of interest to know the status of these microparticles and the risk of VTE with mucosal healing. Perhaps the “quiescent” CD patients have ongoing disease contributing to their increased risk of VTE and increased procoagulation function of microparticles.

Related blog entry:

VTE with IBD | gutsandgrowth

**According to previous expert consensus guidelines, “routine heparin prophylaxis cannot be justified in children until better evidence is available to suggest that the benefit outweigh the risks”  (Turner D, et al. Am J Gastroenterol 2011; 106: 574-88).

FMT -not quite the new Laser

I distinctly remember one of my high school teachers saying that if you asked someone if they were willing to have a serious operation like a brain lobe removal, that most would be unwilling unless there was no other choice.  However, if you told them that you were going to do it with a laser, people would want to get it done right away.  Such was the mesmerizing appeal of the word “laser.”

Fecal microbiota transfer (FMT) certainly does not sound as enticing as a laser treatment. Nevertheless, the authors of a recent report state that “we received interest from patients all over the world to participate.”  That being said, this recent report reintroduces the concept of FMT for ulcerative colitis (UC) (JPGN 2013; 56: 597-601).

In the introduction, the authors note that probiotics, in particular VSL#3, have shown usefulness in the treatment of UC and have noted previous sporadic reports of FMT for inflammatory bowel disease.  This led to their pilot study of 10 subjects (7 to 21 years); this was a single-center, uncontrolled study.  Due to financial constraints, there was no correlation with fecal microbial profiling, histologic/colonoscopic activity, or stool inflammatory markers.

The authors extensively describe their protocol of FMT (240 mL [in four aliquots] daily for five days) including donor exclusion criteria and donor screening.  Participants did not receive any bowel preparation prior to FMT.  The majority of participants had pancolitis;  only one patient had disease limited to proctitis. One of the ten patients could not retain FMT enemas.

Results:

  • Short-term improvement was noted with 7 of 9 (78%) achieving a clinical response within one week and 3 of 9 (33%) achieving a clinical remission.
  • The authors note that 6 of 9 (67%) maintained a clinical response at 1 month.  Although if one examines the study’s figure 2, this graphically demonstrates a fairly meager response in about half of these patients based on their PUCAI score.
  • The authors do not overstate their interpretation of their results.  “This unique biologic is potentially efficacious.”
  • Adverse effects appeared to be mild and self-limiting.

Ultimately if FMT proves efficacious for inflammatory bowel disease, feces with the right microbial mix would be quite valuable.  For now, this study indicates that further research is needed in this area.

Related blog entries:

Simponi (Golimumab) Approved for Ulcerative Colitis

The U.S. Food and Drug Administration on 5/15/13 approved a new use for Simponi (golimumab) injection to treat adults with moderate to severe ulcerative colitis.

Here’s the link:

FDA approves Simponi to treat ulcerative colitis

From the link:

The U.S. Food and Drug Administration today approved a new use for Simponi (golimumab) injection to treat adults with moderate to severe ulcerative colitis.

Simponi works by blocking tumor necrosis factor (TNF), which plays an important role in causing abnormal inflammatory and immune responses. Previously approved to treat rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis (arthritis affecting the joints in the spine and the pelvis), Simponi is now approved to treat adults with moderate to severe ulcerative colitis that is resistant (refractory) to prior treatment or requires continuous steroid therapy.

Ulcerative colitis is a chronic disease that affects about 620,000 Americans. It causes inflammation and ulcers in the inner lining of the large intestine and is one of two main forms of chronic inflammatory bowel disease. The inflammation can lead to abdominal discomfort, gastrointestinal bleeding, production of pus and diarrhea.

“Simponi is an important new treatment option for patients with moderate to severe ulcerative colitis,” said Andrew E. Mulberg, M.D., deputy director of the Division of Gastroenterology and Inborn Errors Products in the FDA’s Center for Drug Evaluation and Research. “It is critical that patients suffering from the serious and painful symptoms of ulcerative colitis have additional treatment options since patients experience the effects of the disease and respond to treatments differently.”

The safety and effectiveness of Simponi for ulcerative colitis were established in two clinical studies. Evaluations of patients included measures of stool frequency, rectal bleeding, endoscopic findings and a physician’s overall assessment.

In the first study, 513 patients with moderate to severe ulcerative colitis who could not tolerate or failed to respond to other therapies were randomly assigned to receive Simponi or a placebo. Results showed that a greater proportion of Simponi-treated patients achieved clinical response, clinical remission and, as seen during endoscopy, had improved appearance of the colon after six weeks compared with the placebo group.

In the second study, 310 patients with moderate to severe ulcerative colitis who were responders to Simponi were randomly assigned to receive Simponi or placebo. A greater proportion of Simponi-treated patients maintained clinical response through week 54 and had clinical remission at both weeks 30 and 54.  

The most common side effects in patients treated with Simponi are upper respiratory infection and redness at the site of injection. Patients treated with Simponi are at increased risk of developing serious infections, invasive fungal infections, reactivation of Hepatitis B infection, lymphoma, heart failure, nervous system disorders and allergic reactions.

Global increases in IBD incidence

Two more studies have shown increasing incidence of pediatric inflammatory bowel disease.

First in Victoria, Australia (mostly Melbourne) (Inflamm Bowel Dis 2013; 19: 1-6).

Over a 60-year span (1950-2009), a retrospective review was undertaken of ulcerative colitis (UC) pediatric patients. In total, 342 children were diagnosed with UC. Key finding: The number of reported cases increased by 11-fold during the study period with a marked increase since 1990 (0.15 –>1.61/100,000).  In addition, recently diagnosed children have had more extensive disease.

Next in Spain (Inflamm Bowel Dis 2013; 19: 73-80).

This retrospective study from hospitals’ databases looked at the incidence between 1996-2009 in the pediatric population (<18 years).  A total of 2107 patients were identified: 1165 with Crohn’s disease, 788 ulcerative colitis, and 154 IBD unclassified. Median age at diagnosis was 12.3 years.  Key finding: in the last 14 years, pediatric IBD incidence has almost tripled (0.9 –>2.8/100,000).

Both of these studies have limitations related to large retrospective reviews in terms of potential problems with capturing all of the patients and the potential for misdiagnosis.  However, the trend is clear.  In addition, these studies show incidence rates comparable to several other Western studies.  The increasing incidence of IBD ‘argue for a common environmental factor in their pathogenesis.’  While interest has focused on microbial factors, the basis for this increased incidence currently remains elusive.

Related blog posts:

Budesonide for Ulcerative Colitis

Budesonide (Uceris) has been formulated with the MMX delivery technology and now has been FDA approved for mild to moderate ulcerative colitis in adults.  The potential advantage of budesonide compared with conventional corticosteroids is for targeting anti-inflammatory activity to the colon with less systemic side effects.  The potential downside includes the high cost.  According to one website (see below), the average wholesale cost is just below $1500 per month.  In addition, only a minority of individuals responded to budesonide in published studies:

Induction of Remission in Studies 1 and 2 (reference below)

Treatment Group

Study 1 n/N (%)

Study 2 n/N (%)

UCERIS 9 mg

22/123 (17.9)

19/109 (17.4)

UCERIS 6 mg

16/121 (13.2)

9/109 (8.3)

Reference Arm*

15/124 (12.1)

13/103 (12.6)

Placebo

9/121 (7.4)

4/89 (4.5)

Treatment Difference between UCERIS 9 mg and Placebo (95% CI)†

10.4% (2.2%, 18.7%)

12.9% (4.6%, 21.3%)

Data for budesonide for pediatric patients with ulcerative colitis is not available.

Clostridium difficile in IBD

A useful review of Clostridium difficile infection (CDI) in the inflammatory bowel disease population has been published and makes several useful points (Inflamm Bowel Dis 2013; 19: 194-204). (Thanks to Ben Gold for suggesting this reference.)

Key points:

  • The incidence of CDI in IBD patients is increasing (faster than general population).  The prevalence of CDI in IBD was nearly eight times greater than non-iBD gastrointestinal patients in a recent population-based study (37.3 cases vs. 4.8 cases per 1000 discharges).
  • Though there is some conflicting data, CDI appears to worsen both short- and long-term outcomes in IBD patients.
  • Carriage (asymptomatic) rates in outpatient IBD patients is higher than the general population (8.2% vs. 1%) according to a recent study.
  • Endoscopic appearance of CDI is rarely classic in the setting of IBD.  Only 13% of hospitalized IBD patients with CDI had pseudomembranes (J Crohns Colitis 2010; 4: 194-98).  Thus, endoscopy has little utility in helping to distinguish IBD flare from superimposed infection.
  • Unique IBD risk factors for CDI: colonic disease and steroid use.
  • The review has a thorough discussion of the available testing and recommends testing only patients with unformed stools unless an ileus is present.
  • For recurrent disease, the authors suggest prolonged tapered vancomycin in adults: 125 mg QID for 10-14 days, then 125 mg BID x 1 week, then 125 mg QD x 1 week, then 125 mg QOD for 2-8 weeks.  Alternative approaches could included fidaxomicin, IVIG/antibody therapy, and fecal transplantation.

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Data on Allopurinol

Given the limited number of therapeutic options for inflammatory bowel disease (IBD), it is important to optimize each individual treatment.  Allopurinol can increase the effectiveness of thiopurines and if used properly can be safe (Inflamm Bowel Dis 2013; 19: 363-69).

The referenced study took place between 2004-2011 and examined 77 patients who failed monotherapy with a thiopurine due to “skewed” metabolism.  The average age of study participant was 38 years (28-45).  23% had previous surgery. Cotreatment with an anti-TNF occurred in 7 patients and with an 5-ASA i 17 patients.

Results:

  • Median 6-thioguanine (6-TGN) levels increased from 145 to 271 pmol/8 x10-to-the-8th. 6-methyl mercaptopurine (6-MMP) concentrations decreased from 10,110 to 265 pmol/8 x10-to-the-8th.
  • Leukopenia occurred in 16%, necessitating dose reductions.
  • Liver tests normalized in 81% with the addition of allopurinol
  • The median azathioprine dose while on combination therapy was 0.64 mg/kg/day and the median 6-mercaptopurine dose was 0.39 mg/kg/day.  While on mono therapy, median values were 2.05 mg/kg/day and 1.23 mg/kg/day respectively.
  • 21% had to discontinue combination therapy.
  • Combination therapy was continued at 6, 12, 24, and 60 months in 87%, 85%, 76%, and 65%.

Take-home Message:

Allopurinol can salvage failed thiopurine monotherapy, but only in a minority of these patients.  Allopurinol should be considered for patients unable to achieve therapeutic 6-TGN levels who have liver toxicity/elevated 6-MMP levels.  Careful attention to dose reduction of the thiopurine is essential to avoid life-threatening bone marrow suppression.

Related blog entry:

Thiopurine Metabolite Testing -NASPGHAN … – gutsandgrowth

Additional references:

  • -Aliment Pharmacol Ther 2010; 31: 640-47. use of allopurinol.
  • -Gastro & Hep 2008; 4: 505. use of allopurinol. Consider if pts unable to enter steroid-free remission AND on adequate AZA/6MP dose. ONLY in those who preferentially metabolize towards 6-MMP (~15% of population); thus subtherapeutic 6-TG levels and increased 6-MMP (>5700). Need adequate WBC >4.5 at start since this will decrease. Check labs every week x 4 at start, then qoweek x 4, then per routine.
  • -IBD 2008; 14: 1678. Experience with allopurinol in children -dose 100mg of allopurinol if >30kg and 50mg if < 30kg. AZA dose decreased to 25% of previous dose. n=13.
  • -Clin Gastro & Hep 2007; 5: 170 (editorial) & 209.  Use of allopurinol (100mg/day) in 20 adults.  Dose of 6-MP reduced 25-50% concomitantly.  Improved disease control w/o hepatotoxicity.  Important to follow counts closely for first 2 months.

How effective are aminosalicylates for pediatric UC?

In a prospective, multicenter, inception cohort study (JPGN 2013; 56: 12-18) with 213 newly diagnosed ulcerative colitis (UC) patients, oral aminosalicylate (5-ASA) therapy was effective in 86 (40%).  That is, 40% were considered to be in corticosteroid-free remission at 1 year using 5-ASA as primary maintenance therapy.

This study took place between 2002-2010.  Of 1669 children enrolled in the registry from 32 sites, 440 (26%) were diagnosed with UC.  Of this group, 353 had followup >1 year and 213 met inclusion/exclusion criteria; all patients had to be treated with only 5-ASA or corticosteroids in the initial 30 days following diagnosis.  Most of those excluded had other therapies.  Among those with primary oral 5-ASA treatment, only 98 started treatment without a steroid induction.

Some interesting aspects of the study group:

  • 82% had pancolitis
  • 62% had moderate/severe disease at diagnosis based on physician global assessment
  • No laboratory or clinical features were associated with a higher likelihood of response
  • Mean daily dosage of 5-ASA was 52 mg/kg/day; 23% had a dose >60 mg/kg/day

The authors note that improved patient adherence and possibly higher 5-ASA dosing schedules may improve response to 5-ASA treatment.

Related blog entry:

Once daily Mesalamine | gutsandgrowth

A-OK for Accutane

Another article has reaffirmed that isotretinoin (Accutane) does not increase the risk of IBD (JAMA Dermatol 2013; 149: 216-20).  Thanks to Mike Hart for this reference. However, this data will not reverse the millions of dollars that have been lost in litigation (Isotretinoin – Wikipedia, the free encyclopedia).

Using a large U.S. health claims database (68 million patients), the authors examined women ages 18-46 years who had received at least one oral contraceptive prescription between 2001-2009.  For each patient with IBD, 20 controls were identified in a nested case-control study design.

In total, 2159 IBD cases (1056 UC, 1103 CD) were matched with 43,180 controls.  Only 10 patients with IBD were exposed to isotretinoin compared with 191 controls.  The adjusted relative risk (RR) for IBD was 0.99; for ulcerative colitis the RR was 1.1 (confidence intervals 0.44-2.7) and for Crohn’s disease the RR was 0.91 (confidence interval 0.91).  For the meta-analysis which was a secondary part of this study, the RR for IBD with 5 studies was 0.94.

Conclusion: The study results do not suggest an increase risk of IBD with isotretinoin use.

Why did previous studies suggest a link between IBD and isotretinoin? The authors note that this is the first study to adjust for two main confounders, mainly a diagnosis of acne and use of oral tetracycline antibiotics.  Oral antibiotics, including tetracyclines, have been associated with IBD previously.  In addition, the design limits the confounding of contraceptive usage.

Limitations of this study:

  • Only women were studied; however, there are no known biologic factors that would make isotretinoin more problematic for males.
  • Other risk factors were not examined: smoking, ethnicity, diet, IBD family history

Additional references:

  • -Am J Gastroenterol 2009; 104: 2774-78.  Population-based study in Winnipeg, <40yrs.  n=1960 cases and 19,419 controls.  No differences in the proportions of IBD cases taking isotretinoin vs controls.  1.2% of IBD cases received isotretinoin prior to IBD diagnosis (n=25) compared with 1.1% of controls (n=213).  Mean # of days prior to IBD dx was 1102.  Thus, isotretinoin unlikely to be causally-associated with idiopathic IBD.
  • -IBD 2009; 12: Supplement -abstract O -0002  Increased risk of UC after isotretinoin.  OR 4.36 for developing UC
  • -Am J Gastroenterol 2009; 104: 2387-93.  7 country study found no causal association between isotretinoin & colitis.

Mortality from IBD

A large Danish cohort provides useful information on the mortality effects of having inflammatory bowel disease (IBD) and how this has changed over the last three decades (Clin Gastroenterol Hepatol 2013; 11: 43-48).

Using a national cohort of all individuals living in Denmark between 1982-2010 (on average 5.3 million), the authors studied 36,080 patients with ulcerative colitis (UC) and 15,361 with Crohn’s disease (CD) in comparison to data from 2,858,096 matched controls (50 controls from each IBD patient) from the general population.  For UC, the median age was 45.2 years and for CD 36.3 years.

Findings:

  • With UC, the first year of diagnosis carried a higher risk of dying (HR 2.43) then rapidly declined to around HR 1.1 after 2 years.  Overall, long-term mortality was increased 10% among UC patients.  Mortality from UC decreased from 1982 to 2010 due to decreased mortalities from gastrointestinal disorders, including colorectal cancer.
  • Mortality was higher among patients diagnosed at younger ages.  Patients diagnosed with UC in childhood or adolescence had a 2.15-fold higher relative mortality than patients diagnosed with UC at 60-79 years.
  • Cause-Specific Mortality: during the first year after UC diagnosis, the HR ratio was increased markedly for gastrointestinal disease (HR 13.3) and infection (HR 9.17).  These areas were most prominent at 10+ years, but the HR ratios had decreased to 1.95 and 1.64 respectively at that time.
  • For CD, mortality was markedly increased in the first year with HR 3.69 and declined to HR 1.53 during years 2-4; HR was 1.49 at 10+ years following diagnosis.  Overall, long-term mortality was increased 50% among CD patients.  Unlike UC, no improvement in mortality rate occurred during the study.
  • Cause-Specific Mortality: during the first year after CD diagnosis, the HR ratio was increased markedly for gastrointestinal disease (HR 23.02) and infection (HR 10.19). These areas were most prominent at 10+ years, but the HR ratios had decreased to 3.67 and 2.70 respectively at that time.  Infections were not increased in the most recent decade, indicating that thiopurines and biologics have not increased the overall risk of fatal infections.
  • While the relative risk of cardiovascular disease was only slightly increased (HR 1.11 for both CD and UC), this is important given the overall frequency of cardiovascular disease in the population.  Presumably, systemic inflammation contributes to the formation of atherosclerosis.
  • Suicide was also increased, especially in the first year after diagnosis (HR 2.05 for UC and HR 1.37 for CD)

Strengths of study: since Denmark has free access to health care and all citizens have a unique 10-digit personal identification, this enables capture of virtually all patients with IBD.  Previous studies have validated the database to be accurate and that the IBD diagnoses have been validated.

Related blog entries: