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Keywords:

  • Crohn's disease;
  • ulcerative colitis;
  • fecal markers;
  • long-term outcome;
  • infliximab;
  • adalimumab

Abstract

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Background:

Fecal calprotectin (FC) concentration is a useful surrogate marker for mucosal healing (MH) during tumor necrosis factor alpha (TNFα)-blocking therapy for inflammatory bowel disease (IBD). Our aim was to evaluate whether a normal FC after induction therapy with TNFα antagonist predicts the outcome of IBD patients during maintenance therapy.

Methods:

Sixty IBD patients (34 Crohn's disease [CD], 26 ulcerative colitis [UC]), treated with TNFα antagonists, either infliximab (n = 42) or adalimumab (n = 18), and having a documented FC level at baseline and after induction therapy were included. Disease activity was evaluated by partial Mayo score without endoscopy or Harvey–Bradshaw index at baseline, after induction, and at 12 months during maintenance therapy.

Results:

After induction, FC was normalized (≤100 μg/g) in 31 patients (52%, median 42 μg/g, range 0–97), whereas the level remained elevated in 29 patients (48%, median 424 μg/g, range 116–5859). At ≈12 months, 26/31 (84%, 18 CD, 8 UC) of the patients with normal FC after induction were in clinical remission, whereas only 11/29 (38%, 9 CD, 2 UC) of those with an elevated (≥100 μg/g) postinduction FC were in clinical remission, P < 0.0001. After induction therapy with TNFα antagonists, a cutoff concentration of 139 μg/g for FC had a sensitivity of 72% and a specificity of 80% to predict a risk of clinically active disease after 1 year.

Conclusions:

A normal FC after induction therapy with TNFα antagonists predicts sustained clinical remission in the majority of patients on scheduled therapy with active luminal disease. (Inflamm Bowel Dis 2012;)

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases (IBDs), characterized by remission and relapses. Clinical activity indices, such as the Harvey–Bradshaw index (HBI)1 in CD and the Mayo score2 in UC indicate the subjective well-being of the patients rather than mucosal healing (MH).3, 4 Over the years the aim of the therapy has been to ameliorate symptoms and avoid relapses. Recently, MH has become a therapeutic target for treatment of IBD.5–8 In CD, long-term MH is associated with a decreased number of disease-related complications, as well as long-term steroid-free remission.9, 10 The tumor necrosis factor alpha (TNFα)-antagonists infliximab and adalimumab are the most effective IBD therapies for induction of MH. The ACCENT I endoscopic substudy showed that infliximab maintenance therapy every 8 weeks is associated with long-term MH in about half of the CD patients.11 Furthermore, the 1-year results from the EXTEND trial, a randomized placebo-controlled study of adalimumab induction and maintenance therapy in patients with moderate to severe ileocolonic CD, have recently shown complete MH occurring significantly more often in adalimumab-treated CD patients than in controls.12 In UC, a randomized, double-blinded, placebo-controlled ACT1 trial demonstrated that MH occurred significantly more often in the infliximab group than in the placebo group.13

As endoscopies are time-consuming and unpleasant for patients, alternative methods have emerged to assess MH. Fecal neutrophil-derived biomarkers for indicators of disease activity and severity, such as calprotectin and lactoferrin, are easily measurable by commercially available enzyme-linked immunosorbent assays (ELISAs), and have been suggested as reliable noninvasive substitutes for endoscopy.14 In IBD, fecal calprotectin (FC) concentration correlates strongly with the excretion of indium-111-labeled granulocytes, considered to be the most sensitive marker of disease activity.15 Furthermore, FC correlates closely with endoscopic and histological grading of disease activity in both UC and CD.16–19 A normalized FC level has shown to be a useful predictor of MH in IBD patients.20 High FC levels may indicate a risk of relapse of IBD during clinical remission, especially in UC and colonic CD.17, 21 As we have demonstrated previously, FC concentrations after TNFα antagonists therapy were significantly lower compared with pretreatment levels, which makes FC a useful surrogate marker for MH.22 The aim of this study was to evaluate whether a normal FC after induction therapy could predict the outcome in IBD patients receiving maintenance therapy with TNFα antagonists.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Patients

During the period April 2005 to April 2010 ≈200 IBD patients were treated with TNFα antagonists at the Division of Gastroenterology at the Helsinki University Central Hospital. In this study we included all patients treated for active luminal disease and having an elevated FC level at baseline and a documented FC concentration after induction with TNFα antagonists. All patients had an established IBD diagnosis based on the usual endoscopic and histological criteria. For induction, 42 patients (16 CD, 26 UC) received infliximab (5 mg/kg either at weeks 0, 2, 6, or at weeks 0, 8), and 18 patients (all CD) received adalimumab (160/80/40 mg every other week or 80/40 mg e.o.w.). After the induction, TNFα therapy was either stopped (no endoscopic or clinical response = primary nonresponders) or continued as a scheduled maintenance therapy for at least 1 year if not relapsing earlier. After the induction therapy, based on the postinduction FC concentration, patients were grouped as normal postinduction calprotectin (calprotectin <100 μg/g) or elevated postinduction calprotectin (calprotectin ≥100 μg/g). Clinical activity indices were collected either from research files or were scored according to data available in patient records. Clinical disease activity was assessed with HBI1 in CD and with Mayo subscore2 in UC at baseline, after induction with TNFα antagonists, and at 1 year. Clinical remission was defined as HBI <4, mildly active disease as HBI 4–7, a moderately active disease as HBI 8–16, and severely active disease as HBI ≥17.23 In the Mayo subscore (without endoscopy), three different clinical variables were graded: frequency of evacuation (0–3), the amount of blood in stool (0–3), and the overall well-being (0–3). Mayo subscore = 0 was defined as remission; 1–3 as mildly active disease; 4–6 as moderately active disease; and >7 as severely active disease.24

Endoscopic Assessment of Disease Activity

Baseline ileocolonoscopy data was available for 57 patients (CD n = 31, UC n = 26). As routinely performed in our unit, endoscopic findings were scored according to the simple endoscopic score for Crohn's disease (SES-CD)25 in CD, and according to the Mayo endoscopic score in UC.2 The SES-CD 0–2 was defined as remission, 3–6 as mildly active disease, 7–15 as moderately active disease, and ≥16 as severely active disease.26 For the Mayo endoscopic subscore, endoscopic findings were graded as normal (0), mild (1), moderate (2), or severe (3); a subscore of 0–1 was defined as remission and a subscore of >2 as active disease.27 Endoscopic reevaluation data were available at ≈1 year (median 11 months, range 9–17) in 38/48 patients on ongoing maintenance therapy (CD n = 27, UC n = 11), with scoring of findings according to the SES-CD or Mayo endoscopic subscore.

FC Measurements

FC concentrations were available at baseline and after induction of all 60 patients and at 1 year for 25/48 patients on maintenance therapy. FC was measured by a quantitative enzyme immunoassay (PhiCal Test, Calpro, Oslo, Norway). In our laboratory, the values quoted as normal were <100 μg/g.29, 30

Statistics

The 60 patients were divided into two groups based on the FC concentration after TNFα antagonist induction: patients with normal FC and those with elevated FC. Each value is presented as a median (range). The primary endpoint for this study was to establish whether patients with normal FC values after induction are more frequently in clinical remission than those with elevated FC values. In order to establish a clinically significant 40% difference in proportion with alpha = 0.05, power = 0.80 when the incidence of remission was 60%, we needed 26 patients in each group. For data analyses we used the Statistical Package for the Social Sciences (SPSS v. 17.0 and PASW 18) for Windows software (SPSS, Chicago, IL). The Mann–Whitney U-test was used to test differences between independent variables, and the Wilcoxon's signed rank-test was used to determine differences between related variables. Fisher's exact test was used to determine differences in binary variables. Significance was set at P < 0.05. The cutoff value for FC to predict the outcomes was calculated using receiver-operator characteristic curve (ROC) analysis. The optimized cutoff level offered the best combination of sensitivity and specificity.

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Data at Baseline and After Induction Therapy

Patient characteristics are shown in Table 1. At baseline an FC measurement was available for all 60 patients (810 μg/g, range 103–12,258). After induction with TNFα antagonists, this was 97 μg/g (range 0–5859, P < 0.001 vs. baseline, Wilcoxon's signed rank test). Of 60 patients, 31 (52%) had normal FC after induction therapy, whereas 29 (48%) patients had an elevated FC. At baseline, median FC concentration did not differ significantly between these two groups (Table 2). In the elevated postinduction calprotectin group, median FC concentrations after induction therapy were lower in patients in clinical remission when compared with those having clinically active disease (clinical remission 204 μg/g, range 116–670 vs. clinically active disease 496 μg/g, range 123–2896, P = 0.025). In the normal calprotectin group after induction therapy 27/31 (84%) had an FC decline more than 75% comparing FC levels at baseline and after induction. Of those patients, 22 (82%) were in clinical remission at 1 year.

Table 1. Patient Characteristics
CharacteristicCrohn's Disease, n=34 (Normal Postinduction Calprotectin Group, n=20)Ulcerative Colitis, n=26 (Normal Postinduction Calprotectin Group, n=11)
  1. GI, gastrointestinal.

Age at onset (median, range)21 (12–50)26 (16–46)
Age at induction (median, range)30 (19–52)29 (18–57)
Gender (female/male)15/1917/9
Disease duration (median, range)7 (1–27)3 (1–24)
Disease behavior (Mb Crohn's)  
 Inflammatory9 
 Stricturing16 
 Penetrating2 
 Inflammatory ± perianal disease4 
 Stricturing ± perianal disease1 
 Penetrating ± perianal disease2 
Disease location  
 Ileum7 
 Colon7 
  Proctitis 0
  Proctosigmoiditis 3
  Pancolitis 13
 Ileocolon17 
 Upper GI1 
 Ileum + upper GI1 
 Colon + upper GI0 
 Ileocolon + upper GI1 
Smoking (no/yes)25/923/3
Prior operation (no/yes)20/1425/1
Harvey-Bradshaw Index (HBI)n=34 
 inactive (0–4)20 (59%) 
 mild (5–7)7 (21%) 
 moderate (8–16)6 (18%) 
 severe (≥17)1 (2%) 
Baseline partial Mayo score n=24
 inactive (0) 0
 mild (1–3) 1 (4%)
 moderate (4–6) 11 (50%)
 severe (≥7) 12 (46%)
Baseline endoscopic Mayo score n=23
 inactive (0) 0
 mild (1) 1 (4%)
 moderate (2) 16 (70%)
 severe (3) 6 (26%)
Table 2. Median Fecal Calprotectin Levels at Baseline, After Induction, and at 1 Year
 All Patients (n=60, CD n=34, UC n=26) Median (Range)Normal Postinduction Calprotectin Groupa (n=31, CD n=20, UC n=11) Median (Range)Elevated Postinduction Calprotectin Groupb (n=29, CD n=14, UC n=15) Median (Range)Comparisonsc
  • a

    Calprotectin <100 μg/g after induction therapy.

  • b

    Calprotectin ≥100 μg/g after induction therapy.

  • c

    P < 0.001 (Mann-Whitney U-test) comparisons of median FC levels between normal postinduction calprotectin group and elevated postinduction calprotectin group.

At baseline810 μg/g (103–12,258), n=60982 μg/g (113–12,258), n=31763 μg/g (103–6717), n=29P = 0.988
After induction therapy97 μg/g (0–5859), n=6042 μg/g (0–97), n=31424 μg/g (116–5859), n=29P < 0.001
At 1 year27 μg/g (0–1361), n=2522 μg/g (0–1361), n=17121 μg/g (2–1066), n=8P = 0.415

Data at 1 Year

At 1 year 37/60 (62%) were in clinical remission (CD n = 27, UC n = 10), 15 patients (25%, all UC) had undergone surgery, and 8 patients (13%, CD n = 7, UC n = 1) had clinically active disease (Fig. 1). CD patients were significantly more often in clinical remission than UC patients, P = 0.001. Of 31 patients in the normal postinduction calprotectin group, 26 (84%) were in clinical remission, whereas only 11 (38%) patients in the elevated postinduction calprotectin group were in clinical remission, P < 0.0001. In the normal postinduction calprotectin group one CD patient in clinical remission discontinued the therapy after 10 months due to pregnancy. In both groups the infliximab dose of one patient was increased during the maintenance therapy. No shortenings of the therapy intervals were made.

thumbnail image

Figure 1. Trial profile.

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Forty-eight patients were on maintenance therapy at ≈1 year. The median time of therapy was 12 months (range 8–17) in these patients. Of 17 measured FC concentrations in the normal postinduction calprotectin group, 13 (76%) were normal (<100 μg/g), whereas only 4/8 (50%) FC concentrations were normal in the elevated postinduction calprotectin group.

Table 3 shows the changes in activity indices in all patients and according to postinduction FC concentration. At 1 year, 38 colonoscopies had been performed (CD n = 27, UC n = 11). Of all patients in clinical remission at 1 year, 24 (62%) were also in endoscopic remission (SES-CD <3 or Mayo endoscopic subscore ≤1), whereas six (38%) patients had either mild or moderate inflammation. In the normal postinduction calprotectin group, 17 (62%) patients were in both clinical and endoscopic remission, while six (38%) patients had active endoscopic inflammation (five with mild or moderate inflammation, and two with severe inflammation in the ileum and/or colon). In the elevated postinduction calprotectin group, only seven (33%) patients were in clinical and endoscopic remission at 1 year, and eight (67%) patients had mild or moderate endoscopic inflammation.

Table 3. Activity Indices and at Baseline, After Induction, and at the End of the Study
 Normal Postinduction Calprotectin Group (n=31, CD n=20, UC n=11)Elevated Postinduction Calprotectin Group (n=29, CD n=14, UC n=15)P
  1. Values presented as median (range).

  2. CD, Crohn's disease; UC, ulcerative colitis; SES-CD, simple endoscopic score for Crohn's disease.

Harvey-Bradshaw Index (HBI)   
 -at baseline4 (0–22, n=20)4 (0–13, n=14)0.958
 -after induction0 (0–8, n=20)1 (0–6, n=14)0.144
 -at the end of the study0 (0–16, n=20)2 (0–8, n=12)0.022
SES-CD   
 -at baseline14 (4–26, n=17)10 (0–32, n=14)0.183
 -after induction3 (0–26, n=15)9 (2–12, n=11)0.017
 -at the end of the study1 (0–26, n=15)5 (0–12, n=12)0.243
Partial Mayo score   
 -at baseline6 (4–8, n=10)7 (2–8, n=14)0.631
 -after induction0 (0–5, n=11)6 (1–7, n=12)<0.001
 -at the end of the study0 (0–0, n=9)2 (0–3, n=4)0.005
Endoscopic Mayo subscore   
 -at baseline2 (2–3, n=10)2 (1–3, n=13)0.143
 -after induction0 (0–2, n=10)2 (1–3, n=9)<0.001
 -at the end of the study0 (0–1, n=8)1 (0–2, n=3)0.068

The ROC curve constructed to predict the relapse risk according to the FC level is shown in Figure 2. The value of 139 μg/g was optimized as the best cutoff, with a sensitivity of 72% and a specificity of 80%, AUC 0.838 (0.724–0.952). Because of small subgroups, no separate cutoff levels were reasonable to calculate for CD and UC patients. Smoking (odds ratio (OR) 1.19, 95% confidence interval [CI] 4.32–0.33, P = 1), gender (OR 0.33; 95% CI 0.11–1.00, P = 0.064), or chosen TNFα antagonists (OR 0.35; 95% CI 0.10–1.23, P = 0.147) did not significantly affect the outcome, i.e., clinical remission. Another ROC curve was constructed to predict the positive outcome according to the decline of the FC level after induction (Fig. 3). The decline of 88% gives the maximum sum of sensitivity (87%) and specificity (65%), AUC 0.771 (0.652–0.890), P < 0.001.

thumbnail image

Figure 2. ROC curve of FC to predict relapse in IBD patients. The best cutoff value after induction was 139 μg/g, with a sensitivity of 72% and a specificity of 80%, AUC 0.838 (0.724–0.951).

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thumbnail image

Figure 3. ROC curve of the best value of FC decline to predict positive response in IBD patients. The value is 88%, with a sensitivity of 87% and a specificity of 65%, AUC 0.771 (0.652–0.890).

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DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

In this study a normal FC concentration after the induction therapy was shown to predict 1-year clinical outcome in patients with active luminal IBD. Patients with a normal FC concentration after induction with TNFα blocking agents seemed to sustain clinical remission significantly more often than those with an abnormal postinduction FC concentration. Smoking, gender, or chosen TNFα antagonists did not significantly correlate with the prognosis.

The ACCENT I endoscopic substudy, the EXTEND trial, and ACT1 trial have shown that TNF-antagonist maintenance therapy induces MH significantly more often than in control groups.11–13 In a large cohort study, Schnitzler et al30 showed that in patients with scheduled infliximab treatment, MH was associated with less complications and better long-term outcome. Recently, Baert et al10 demonstrated that complete MH can lead to significantly higher steroid-free remission rates in patients with early-stage CD for as long as 4 years after start of therapy. We have previously presented an analysis of the use of endoscopy to monitor the response of infliximab therapy in CD in a clinical setting. This study showed that the endoscopic findings after induction therapy were highly predictive of the 1-year response rate in which MH occurred for a majority of initial responders. On the other hand, in the nonresponders group, continuation of infliximab infrequently resulted in MH.31

Røseth et al20 were the first to demonstrate that MH can be determined by assessment of calprotectin in a simple stool sample. In that study, histological examination showed normal findings in 38 of 45 patients having a normal FC level, and the rest had only mild inflammation in the biopsies. We have shown previously that FC is a useful surrogate marker for MH in CD patients receiving induction with TNFα antagonists.21 Furthermore, FC has proven to be a good marker for predicting clinical relapse.17, 22, 32, 33 Tibble et al17 found that FC levels differed significantly between the nonrelapse group and the relapse group. Costa et al22 reported FC to be a stronger predictor of clinical relapse in UC than in CD. A more recent study showed that an FC level over 130 mg/kg predicts clinical relapse in UC and in colonic CD.32 Similar results have been shown in a study reporting a 6-fold increase in relapse rate in 1 year in UC with FC over 120 μg/g, and a 4-fold increase in CD with an FC level over 200 μg/g at baseline.33

To the best of our knowledge, no previous full reports exist showing the usefulness of FC concentration in estimation of outcome after induction with TNFα antagonists. Published only as an abstract, Guidi et al34 pointed out that a normalization of FC correlates significantly with the clinical response after anti-TNFα induction therapy. In that study, FC more than 150 mg/kg after induction therapy showed an increased risk of relapse at 1 year. This is in line with the current study, where an FC cutoff concentration of 139 μg/g seems to predict the relapse risk during anti-TNFα maintenance therapy fairly well. We were also able to show that the outcome was almost equal when comparing patients with normal FC level and 75% decline of FC level after induction. In this study the best predictive value of decline of FC was 88%. It is reasonable to consider patients with FC decline over 88% as responders as well as those with a normal FC level.

Based on the current study, a normal postinduction FC seems also to predict endoscopic remission after 1-year maintenance therapy. Sixty percent of the normal postinduction calprotectin group were in endoscopic remission at 1 year, whereas only about one-third of patients in the elevated postinduction calprotectin group.

Our study has some limitations. As the study was retrospective, the patient group was heterogeneous. We included both CD and UC patients receiving either infliximab or adalimumab. Due to the treatment protocol for luminal CD in our clinic, induction with infliximab was mainly given in luminal disease at weeks 0 and 8, and in a fewer cases in three infusions (at weeks 0, 2, and 6). The induction doses of adalimumab also varied, especially at the beginning of the study period. However, our study reflects well the daily clinical practice.

This retrospective clinical study provides evidence that a normal FC after induction with TNFα antagonists predicts sustained remission in the majority of patients with active luminal disease with scheduled treatment.

REFERENCES

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES
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    Direct Link:
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