Maintenance of clinical benefit in Crohn's disease patients after discontinuation of infliximab: long-term follow-up of a single centre cohort

Relapse rates after withdrawal versus maintaining biologic therapy in IBD patients with prolonged remission

Biologic treatment withdrawal in inflammatory bowel disease patients with prolonged remission may lead to benefits but also increases the risk of getting a relapse. The risk of relapse after biologic withdrawal according to the Dutch STOP-criteria is still unknown. The aim of this study was to compare the cumulative incidence of relapse in inflammatory bowel disease patients that discontinued biologic therapy after applying the STOP-criteria with patients who maintained biologic therapy. We performed a mono-centre, observational, retrospective study by evaluating relapse risk of patients treated with biologic agents who discontinued this treatment according to the STOP-criteria (STOP-group) compared to patients who were in remission for more than 3 years before withdrawal (LATERSTOP-group) and patients who continued their biologic (MAINTAIN-group). The cumulative risk was calculated at 12 and 36 months using the log-rank test to compare Kaplan-Meier curves. Eighty-three of 398 patients that used biologics between 1 January 2010 and 1 January 2020 were included. The cumulative relapse incidences in the STOP-group and the LATERSTOP-group were, respectively, 29% and 42% at 12 months and 47% versus 58% at 36 months. Patients in the MAINTAIN-group showed a lower (p = 0.03) cumulative relapse incidence of 10% at 12 months and 18% at 36 months. Patients who discontinued their biologic therapy according to the STOP-criteria had significantly more relapses at 12 and 36 months than patients who maintained biologic treatment.

Prediction of Relapse After Anti-Tumor Necrosis Factor Cessation in Crohn's Disease: Individual Participant Data Meta-analysis of 1317 Patients From 14 Studies

BACKGROUND & AIMS

Tools for stratification of relapse risk of Crohn's disease (CD) after anti-tumor necrosis factor (TNF) therapy cessation are needed. We aimed to validate a previously developed prediction model from the diSconTinuation in CrOhn's disease patients in stable Remission on combined therapy with Immunosuppressants (STORI) trial, and to develop an updated model.

METHODS

Cohort studies were selected that reported on anti-TNF cessation in 30 or more CD patients in remission. Individual participant data were requested for luminal CD patients and anti-TNF treatment duration of 6 months or longer. The discriminative ability (concordance-statistic [C-statistic]) and calibration (agreement between observed and predicted risks) were explored for the STORI model. Next, an updated prognostic model was constructed, with performance assessment by cross-validation.

RESULTS

This individual participant data meta-analysis included 1317 patients from 14 studies in 11 countries. Relapses after anti-TNF cessation occurred in 632 of 1317 patients after a median of 13 months. The pooled 1-year relapse rate was 38%. The STORI prediction model showed poor discriminative ability (C-statistic, 0.51). The updated model reached a moderate discriminative ability (C-statistic, 0.59), and included clinical symptoms at cessation (hazard ratio [HR], 2.2; 95% CI, 1.2-4), younger age at diagnosis (HR, 1.5 for A1 (age at diagnosis ≤16 years) vs A2 (age at diagnosis 17 - 40 years); 95% CI, 1.11-1.89), no concomitant immunosuppressants (HR, 1.4; 95% CI, 1.18-172), smoking (HR, 1.4; 95% CI, 1.15-1.67), second line anti-TNF (HR, 1.3; 95% CI, 1.01-1.69), upper gastrointestinal tract involvement (HR, 1.3 for L4 vs non-L4; 95% CI, 0.96-1.79), adalimumab (HR, 1.22 vs infliximab; 95% CI, 0.99-1.50), age at cessation (HR, 1.2 per 10 years younger; 95% CI, 1-1.33), C-reactive protein (HR, 1.04 per doubling; 95% CI, 1.00-1.08), and longer disease duration (HR, 1.07 per 5 years; 95% CI, 0.98-1.17). In subanalysis, the discriminative ability of the model improved by adding fecal calprotectin (C-statistic, 0.63).

CONCLUSIONS

This updated prediction model showed a reasonable discriminative ability, exceeding the performance of a previously published model. It might be useful to guide clinical decisions on anti-TNF therapy cessation in CD patients after further validation.

Withdrawal of Combination Immunotherapy in Paediatric Inflammatory Bowel Disease-An International Survey of Practice

OBJECTIVES

To assess current practices around the use of combination immunosuppression in paediatric inflammatory bowel disease (PIBD) with a focus on the subsequent withdrawal process.

METHODS

A web-based, 43-question survey.

RESULTS

Surveys were completed by 70 paediatric gastroenterologists (PGs) from 27 nations across Europe, North America, Oceania and Asia from 62 centres covering approximately 15,000 PIBD patients (median of 200 patients [interquartile range (IQR) 130-300] per centre). Routine use of co-immunosuppression was significantly higher with infliximab (IFX) versus adalimumab (ADL) ([61/70, 87.1%] compared with [23/70, 32.9%]; P < 0.01). Thiopurines (azathioprine [AZA] or 6-mercaptopurine) were the preferred option overall for co-immunosuppression. They were favoured with either IFX or ADL (76% and 77%, respectively) and in both ulcerative colitis (UC) and Crohn disease (CD) (84% and 69%) compared with methotrexate (MTX).Immunomodulators were the preferred choice as the initial drug to be withdrawn from the combination therapy rather than anti-tumour necrosis factor-alpha (anti-TNFα) therapy (59/67, 88% [P < 0.01]). The most common withdrawal time was after 6-12 months, with this decision usually based on clinical assessment rather than a scheduled withdrawal time (51/67, 76% vs 16/67, 24%). Indicators of mucosal healing and therapeutic drug monitoring results tended to be the most important "clinical factors" in the withdrawal decision (P = 0.05).

CONCLUSION

Most PG's favour initial withdrawal of immunomodulator (usually thiopurines) rather than biologic therapy in the step-down process, usually after 6-12 months based on sustained clinical remission. This survey precedes an in-depth, multicentre study of clinical outcomes of withdrawal of co-immunosuppression in PIBD.

Clinical outcome after anti-tumour necrosis factor therapy discontinuation in 1000 patients with inflammatory bowel disease: the EVODIS long-term study

BACKGROUND

The long-term outcome of patients after antitumour necrosis factor alpha (anti-TNF) discontinuation is not well known.

AIMS

To assess the risk of relapse in the long-term after anti-TNF discontinuation.

METHODS

This was an extension of the evolution after anti-TNF discontinuation in patients with inflammatory bowel disease (EVODIS) study (Crohn's disease or ulcerative colitis patients treated with anti-TNFs in whom these drugs were withdrawn after achieving clinical remission) based in the same cohort of patients whose outcome was updated. Clinical remission was defined as a Harvey-Bradshaw index ≤4 points in Crohn's disease, a partial Mayo score ≤2 in ulcerative colitis and the absence of fistula drainage despite gentle finger compression in perianal disease.

RESULTS

This was an observational, retrospective, multicenter study. A total of 1055 patients were included. The median follow-up time was 34 months. The incidence rate of relapse was 12% per patient-year (95% confidence interval [CI] = 11-14). The cumulative incidence of relapse was 50% (95% CI = 47-53): 19% at one year, 31% at 2 years, 38% at 3 years, 44% at 4 years and 48% at 5 years of follow-up. Of the 60% patients retreated with the same anti-TNF after relapse, 73% regained remission. Of the 75 patients who did not respond, 48% achieved remission with other therapies. Of the 190 patients who started other therapies after relapse, 62% achieved remission with the new treatment.

CONCLUSIONS

A significant proportion of patients who discontinued the anti-TNF remained in remission. In case of relapse, retreatment with the same anti-TNF was usually effective. Approximately half of the patients who did not respond after retreatment achieved remission with other therapies.

Combination Immunotherapy Use and Withdrawal in Pediatric Inflammatory Bowel Disease-A Review of the Evidence

Evidence-based guidelines have been developed outlining the concomitant use of anti-tumor necrosis factor alpha (anti-TNF) agents and immunomodulators including azathioprine (AZA) and methotrexate (MTX) in both adult and pediatric populations. However, there exists a paucity of data guiding evidence-based strategies for their withdrawal in pediatric patients in sustained remission. This narrative review focuses on the available pediatric evidence on this question in the context of what is known from the larger body of evidence available from adult studies. The objective is to provide clarity and practical guidance around who, what, when, and how to step down pediatric patients with inflammatory bowel disease (IBD) from combination immunotherapy. Outcomes following withdrawal of either of the two most commonly used anti-TNF therapies [infliximab (IFX) or adalimumab (ADA)], or immunomodulator therapies, from a combination regimen are examined. Essentially, a judicious approach must be taken to identify a significant minority of patients who would benefit from treatment rationalization. We conclude that step-down to anti-TNF (rather than immunomodulator) monotherapy after at least 6 months of sustained clinical remission is a viable option for a select group of pediatric patients. This group includes those with good indicators of mucosal healing, low or undetectable anti-TNF trough levels, lack of predictors for severe disease, and no prior escalation of anti-TNF therapy. Transmural healing and specific human leukocyte antigen (HLA) typing are some of the emerging targets and tools that may help facilitate improved outcomes in this process. We also propose a simplified evidence-based schema that may assist in this decision-making process. Further pediatric clinical studies are required to develop the evidence base for decision-making in this area.

Clinical outcomes, predictors of prognosis and health economics consequences in IBD patients after discontinuation of the first biological therapy

BACKGROUND

In real-world clinical practice, biologics in inflammatory bowel diseases (IBD) may be discontinued for a variety of reasons, including discontinuation initiated by gastroenterologists. The aims of the study are to report outcomes after discontinuation and predictors of prognosis after a minimum follow-up of 24 months; outcomes of gastroenterologist-initiated discontinuation with resulting direct cost implications on the health system were also studied.

METHODS

IBD patients who discontinued their first-use biologics between January 2013 and December 2016 were identified at our tertiary centre. Reasons for discontinuation and pre-defined adverse outcomes (AO) were recorded. Data were analysed using univariable and multivariable logistic regressions within a machine learning technique to predict AO. Gastroenterologist-initiated discontinuations were analysed separately, and Kaplan-Meier survival analysis performed; direct costs of AO due to discontinuation were assessed.

RESULTS

A total of 147 patients discontinued biologics (M = 74; median age 39 years; Crohn's Disease = 110) with median follow-up of 40 months (range 24-60 months). In the total cohort, there were fewer AO among gastroenterologist-initiated discontinuations compared with patient-initiated; 54% (of the total group) had AO within 6 months. Among 59 gastroenterologist-initiated discontinuations, 23 (40%) had IBD-related AO within 6 months and 53 (90%) patients had AO by end of follow-up. Some 44 (75%) patients needed to restart biologics during follow-up, and direct costs due to AO and restart of biologics were high.

CONCLUSIONS

The proportion of patients who have AO following discontinuation of biologics is high; clinicians need to carefully consider predictors of poor prognosis and high relapse rates when discussing discontinuation. The direct costs of managing AO probably offset theoretical economic gains, especially in the era where cost of biologics is reducing. Biologics should probably be continued without interruptions in most patients who have achieved remission for the duration these remain effective and safe.

Prevention of Postoperative Recurrence in CD: Tailoring Treatment to Patient Profile

Crohn's disease (CD) is an immune-mediated condition characterized by the transmural inflammation of the gut tissue, associated with progressive bowel damage often leading to surgical intervention. As operative resection of the damaged segment is not curative, a majority of patients undergoing intestinal resections for complicated CD present disease recurrence within 3 years after the intervention. Postoperative recurrence can be defined as endoscopic, clinical, radiological or surgical. Endoscopic recurrence rates within 1 year exceed 60% and the severity, according to the Rutgeerts' score, is associated with worse prognosis and can predict clinical recurrence (in up to 1/3 of the patients). Most importantly, about 50% of patients will undergo a reoperation after 10 years of their first intestinal resection. Therefore, the prevention of postoperative recurrence in CD remains a challenge in clinical practice and should be properly managed. We aim to summarize the most recent data on the definition, risk factors, assessment and treatment of postoperative CD recurrence.

Efficiency and safety of one-year anti-TNF-α treatment in Crohn's disease: a Polish single-centre experience

Introduction

Anti-TNF-α therapy of Crohn’s disease (CD) represents considerable progress in inflammatory bowel disease (IBD) treatment; however, many patients still require surgical intervention. The Polish National Insurance Fund currently only covers up to 2 years of infliximab (IFX) therapy in CD patients and 1 year of adalimumab (ADA).

Aim

To estimate the effectiveness and side effects of the anti-TNF-α Polish therapeutic program in CD patients.

Material and methods

In this retrospective study, medical documentation of 80 CD patients treated with anti-TNF-α (IFX or ADA) was analysed. Fifty-two patients finished 1 year of therapy, and 28 individuals did not complete it due to lack of response to treatment or severe side effects.

Results

After treatment, 27 (67.50%) patients achieved a semi-annual remission and 14 (35%) achieved yearly remission. Twenty percent of patients experienced severe side effects such as anaphylactic shock, pneumonia, shingles, or upper respiratory tract infections. A strong negative correlation between the number of patients in remission and the period since therapy termination (r = –0.996, p < 0.001) was found. During the 1-year follow-up, 20 patients were re-enrolled in the biological therapy program (the median time to next therapy was 231 days IQR: 126.5–300.5)

Conclusions

Anti-TNF-α treatment in CD is relatively safe. The restricted time period of the therapy affects the clinical course of the disease and entails the need to resume biological therapy.

Prevalence, Safety and Long-Term Retention Rates of Biologics in Hong Kong from 2001 to 2015

BACKGROUND

Biologic agents were initially introduced as treatment for rheumatoid arthritis (RA) but have since been used for other medical conditions. As new biologics become increasingly widespread in treatment regimens, it is important to understand their safety and utilization in the post-marketing context.

PURPOSE

The aim of this study was to investigate long-term prescribing patterns and the safety of biologics in real clinical settings in Hong Kong.

METHODS

This was a population-based drug utilization study in Hong Kong using a territory-wide electronic medical database Clinical Data Analysis and Reporting System (CDARS). Patients who received biologic treatments from 2001 to 2015 were identified and their corresponding demographic and clinical details retrieved from CDARS. The annual prevalence of biologic prescriptions, the long-term retention rates and incidence rates of infections associated with biologic treatments were evaluated.

RESULTS

A total of 30,298 patients (male: 44%) prescribed biologic treatments were identified from CDARS from 2001 to 2015. The annual prevalence of biologic prescriptions increased from 0.1 to 16.1 per 100 persons for both sexes. Infliximab had the highest first-year retention rate of 95.6% among all biologics and continuously attained the highest retention rate from second to fifth year. The overall incidence rate of serious infections was less than five per 100 person-years. Specifically, the incidence rates of tuberculosis, upper and lower respiratory infections and herpes zoster were 0.52, 3.24, 4.99 and 1.01 per 100 person-years, respectively.

CONCLUSION

This population-based study revealed an increasing prevalence of biologic prescribing. Results from the study described the long-term retention rates and incidence rates of serious infections of biologic treatments for all indications, and confirmed the safety of biologic treatments. Since this study provides an overview of all biologic utilization, further studies on cost effectiveness, safety and compliance of treatment in different patient groups are still warranted.

Long-term clinical outcome after infliximab discontinuation in patients with inflammatory bowel disease

OBJECTIVES

We investigated the long-term clinical outcome and risk factors for clinical relapse in inflammatory bowel disease (IBD) patients after stopping infliximab (IFX).

MATERIALS AND METHODS

We retrospectively reviewed the medical records of IBD patients who were treated with IFX in four university hospitals in South Korea. Among them, patients who discontinued scheduled IFX therapy with a favorable disease course were enrolled. Clinical relapse was defined as an increase in disease activity, addition of new drugs, or abdominal surgery.

RESULTS

In total, 28 ulcerative colitis (UC) patients and 17 Crohn's disease (CD) patients were enrolled. The median duration of follow-up after discontinuation was 41 months (range: 8-109 months) in UC patients and 141 months (range: 66-262 months) in CD patients. The cumulative probability of relapse at 12 months was 32.1% in UC patients and 30.7% in CD patients. Fewer IFX infusions and a shorter duration of mesalamine treatment after IFX discontinuation were risk factors for relapse after IFX discontinuation in UC patients (p = .04 and .01, respectively). In CD patients, a higher erythrocyte sedimentation rate and CRP at IFX discontinuation and a shorter duration of azathioprine treatment after IFX discontinuation were risk factors for relapse (p = .03, .03 and .01, respectively).

CONCLUSIONS

Approximately 30% of IBD patients who responded to IFX therapy experienced relapse within 1 year after discontinuation. We identified several risk factors for relapse. Further studies should identify factors predictive of the disease course after discontinuing IFX maintenance therapy.

Anti-TNF Therapy in Crohn's Disease

Crohn’s disease (CD) accounts for a variety of clinical manifestations or phenotypes that stem from chronic inflammation in the gastrointestinal tract. Its worldwide incidence is increasing including younger or childhood-onset of disease. The natural history of Crohn’s disease is characterized by a remitting and relapsing course that progresses to complications and surgery in most patients. The goals of treatment are to achieve clinical and endoscopic remission, to avoid disease progression and minimise surgical resections. Medical treatment usually features antibiotics, corticosteroids, immunomodulators (thiopurines, methotrexate). Anti-TNF (tumour necrosis factor) therapy was approved for use in Crohn’s disease in 1998, and has changed the paradigm of treatment, leading to improved rates of response and remission in patients. There are significant considerations that need to be borne in mind, when treating patients including immunogenicity, safety profile and duration of treatment.

Subtherapeutic Infliximab Trough Levels and Complete Mucosal Healing Are Associated With Sustained Clinical Remission After Infliximab Cessation in Paediatric-onset Crohn's Disease Patients Treated With Combined Immunosuppressive Therapy

BACKGROUND AND AIMS

We aimed to investigate the outcome in paediatric-onset Crohn's disease patients who had discontinued infliximab after maintaining clinical remission with combined immunosuppression, and to determine factors associated with clinical relapse.

METHODS

We conducted a retrospective observational study of 63 paediatric-onset Crohn's disease patients who had stopped scheduled infliximab during sustained corticosteroid-free clinical remission for at least 1 year with infliximab and azathioprine, and were followed up for at least 1 year thereafter. Cumulative relapse rates and the median time to relapse were estimated statistically. Factors at cessation were also evaluated for their association with clinical relapse.

RESULTS

After a median follow-up period of 4.3 years [range, 1-7.5 years], 60.3% [38/63] of patients had experienced clinical relapse. According to Kaplan-Meier survival analysis, the estimated cumulative relapse rates at 1, 4, and 6 years were 19.0%, 62.2%, and 75.2%, respectively, and the median relapse time was 3.3 years from infliximab cessation. According to multivariate Cox proportional hazard regression analysis, infliximab trough levels of ≥2.5 μg/mL and incomplete mucosal healing were associated with clinical relapse (hazard ratio [HR] = 7.199, 95% confidence interval [CI] = 1.641-31.571, p = 0.009 and HR = 3.628, 95% CI = 1.608-8.185, p = 0.002, respectively). Although re-treatment with infliximab was effective in 90.9% [30/33] of patients, 7.9% [3/38] eventually underwent surgery within 1 year of relapse.

CONCLUSIONS

Considering the high cumulative relapse rates in the long term and cases of severe relapse requiring surgery, discontinuing infliximab in paediatric-onset Crohn's disease patients is currently inadvisable. However, there may be a subgroup of patients who are good candidates for infliximab withdrawal.

Withdrawal of immunosuppressant or biologic therapy for patients with quiescent Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic, relapsing and remitting disease of the gastrointestinal tract that can cause significant morbidity and disability. Current treatment guidelines recommend early intervention with immunosuppressant or biological therapy in high-risk patients with a severe disease phenotype at presentation. The feasibility of therapeutic de-escalation once remission is achieved is a commonly encountered question in clinical practice, driven by patient and clinician concerns regarding safety, adverse events, cost and national regulations. Withdrawal of immunosuppressant and biologic drugs in patients with quiescent CD may limit adverse events and reduce healthcare costs. Alternatively, stopping these drug therapies may result in negative outcomes such as disease relapse, drug desensitization, bowel damage and need for surgery.

OBJECTIVES

To assess the feasibility and safety of discontinuing immunosuppressant or biologic drugs, administered alone or in combination, in patients with quiescent CD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and the Cochrane IBD Group Specialized Register from inception to 19 December 2017. We also searched the reference lists of potentially relevant manuscripts and conference proceedings to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and prospective cohort studies that followed patients for a minimum duration of six months after drug discontinuation were considered for inclusion. The patient population of interest was adults (> 18 years) with CD (as defined by conventional clinical, endoscopic or histologic criteria) who had achieved remission while receiving immunosuppressant or biologic drugs administered alone or in combination. Patients then discontinued the drug regimen following a period of maintenance therapy of at least six months. The comparison was usual care (i.e. continuation of the drug regimen).

DATA COLLECTION AND ANALYSIS

The primary outcome measure was the proportion of patients who relapsed following discontinuation of immunosuppressant or biologic drugs, administered alone or in combination. Secondary outcomes included: the proportion of patients who responded to the reintroduction of immunosuppressant or biologic drugs, given as monotherapy or combination therapy; the proportion of patients who required surgery following relapse; the proportion of patients who required hospitalization for CD following relapse; the proportion of patients who developed new CD-related complications (e.g. fistula, abscesses, strictures) following relapse; the proportion of patients with elevated biomarkers of inflammation (CRP, fecal calprotectin) in those who stop and those who continue therapy; the proportion of patients with anti-drug antibodies and low serum trough drug levels; time to relapse; and the proportion of patients with adverse events, serious adverse events and withdrawal due to adverse events. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (95% CI). Data were analyzed on an intention-to-treat basis where patients with missing outcome data were assumed to have relapsed. The overall quality of the evidence supporting the primary and secondary outcomes was assessed using the GRADE criteria.

MAIN RESULTS

A total of six RCTs (326 patients) evaluating therapeutic discontinuation in patients with quiescent CD were eligible for inclusion. In four RCTs azathioprine monotherapy was discontinued, and in two RCTs azathioprine was discontinued from a combination therapy regimen consisting of azathioprine with infliximab. No studies of biologic monotherapy withdrawal were eligible for inclusion. The majority of studies received unclear or low risk of bias ratings, with the exception of three open-label RCTs, which were rated as high risk of bias for blinding. Four RCTs (215 participants) compared discontinuation to continuation of azathioprine monotherapy, while two studies (125 participants) compared discontinuation of azathioprine from a combination regimen to continuation of combination therapy. Continuation of azathioprine monotherapy was shown to be superior to withdrawal for risk of clinical relapse. Thirty-two per cent (36/111) of azathioprine withdrawal participants relapsed compared to 14% (14/104) of participants who continued with azathioprine therapy (RR 0.42, 95% CI 0.24 to 0.72, GRADE low quality evidence). However, it is uncertain if there are any between-group differences in new CD-related complications (RR 0.34, 95% CI 0.06 to 2.08, GRADE low quality evidence), adverse events (RR 0.88, 95% CI 0.67 to 1.17, GRADE low quality evidence), serious adverse events (RR 3.29, 95% CI 0.35 to 30.80, GRADE low quality evidence) or withdrawal due to adverse events (RR 2.59, 95% CI 0.35 to 19.04, GRADE low quality evidence). Common adverse events included infections, mild leukopenia, abdominal symptoms, arthralgias, headache and elevated liver enzymes. No differences between azathioprine withdrawal from combination therapy versus continuation of combination therapy were observed for clinical relapse. Among patients who continued combination therapy with azathioprine and infliximab, 48% (27/56) had a clinical relapse compared to 49% (27/55) of patients discontinued azathioprine but remained on infliximab (RR 1.02, 95% CI 0.68 to 1.52, P = 0.32; GRADE low quality evidence). The effects on adverse events (RR 1.11, 95% CI 0.44 to 2.81, GRADE low quality of evidence) or serious adverse events are uncertain (RR 1.00, 95% CI 0.21 to 4.66; GRADE very low quality of evidence). Common adverse events in the combination therapy studies included infections, liver test elevations, arthralgias and infusion reactions.

AUTHORS' CONCLUSIONS

The effects of withdrawal of immunosuppressant therapy in people with quiescent Crohn's disease are uncertain. Low quality evidence suggests that continuing azathioprine monotherapy may be superior to withdrawal for avoiding clinical relapse, while very low quality evidence suggests that there may be no difference in clinical relapse rates between discontinuing azathioprine from a combination therapy regimen, compared to continuing combination therapy. It is unclear whether withdrawal of azathioprine, initially administered alone or in combination, impacts on the development of CD-related complications, adverse events, serious adverse events or withdrawal due to adverse events. Further high-quality research is needed in this area, particularly double-blind RCTs in which biologic therapy or an immunosuppressant other than azathioprine is withdrawn.

European Crohn's and Colitis Organisation Topical Review on Treatment Withdrawal ['Exit Strategies'] in Inflammatory Bowel Disease

Clinically effective therapies now exist for remission maintenance in both ulcerative colitis [UC] and Crohn's Disease [CD]. For each major class of IBD medications [5-aminosalicyclates, immunomodulators, and biologic agents], used alone or in combination, there is a risk of relapse following reduction or cessation of treatment. A consensus expert panel convened by the European Crohn's and Colitis Organisation [ECCO] reviewed the published literature and agreed a series of consensus practice points. The objective of the expert consensus is to provide evidence-based guidance for clinical practice so that physicians can make informed decisions in partnership with their patients. The likelihood of relapse with stopping each class of IBD medication is reviewed. Factors associated with an altered risk of relapse with withdrawal are evaluated, and strategies to monitor and allow early identification of relapse are considered. In general, patients in clinical, biochemical, and endoscopic remission are more likely to remain well when treatments are stopped. Reintroduction of the same treatment is usually, but not always, successful. The decision to stop a treatment needs to be individualized, and shared decision making with the patient should take place.

Discontinuation of Biological Treatments in Inflammatory Bowel Disease: A Concise Pragmatic Review

Despite the proven efficacy of biological drugs for inflammatory bowel disease, these therapies are costly and do carry some risks, providing incentive for exploring strategies to discontinue therapy in patients with prolonged remission. We presently review multiple cohort studies indicating the overall risk of relapse after stopping an anti-tumor necrosis factor (TNF) in inflammatory bowel disease patients is roughly 40% at 12 months after therapy cessation. Despite methodological differences across studies, it appears that patients without deep remission (ie, patients with endoscopic or biomarker evidence of inflammation) are at increased risk of relapse after stopping anti-TNF, as are those with high-adequate levels of anti-TNF before stopping. In patients who relapse after anti-TNF cessation, retreatment with the same biological seems to reinduce clinical response in most patients. Immunological reasons responsible for this high success rate for retreatment are elucidated, but resorting to retreatment also implies a small but finite risk of a severe flare leading to surgery, which should be borne in mind. Thus, stopping attempts should probably be reserved for patients with low risk for severe outcome should a relapse occur. Proactive endoscopic monitoring after drug cessation is imperative to reduce these risks. The recently introduced concept of treatment-cycles is discussed, along with a pragmatic algorithm of decision tree for therapy discontinuation in the selected appropriate patients.

Outcome of elective withdrawal of anti-tumour necrosis factor-α therapy in patients with Crohn's disease in established remission

BACKGROUND AND AIMS

Outcomes of cessation of anti-TNF therapy for Crohn's disease (CD) in clinical and/or endoscopic remission in routine clinical practice is uncertain. This study aimed to evaluate clinical outcomes and factors associated with relapse in CD patients following formal disease assessment and elective anti-TNF withdrawal.

METHODS

Prospective observational study of CD patients in whom anti-TNF therapy was stopped electively after ≥12months and follow-up of ≥6months. Investigations at assessment prior to cessation included ≥1 of clinical assessment, endoscopic and/or imaging. Relapse was defined as recurrent symptoms of CD requiring medical or surgical therapy.

RESULTS

Eighty-six patients received anti-TNF for a median duration of 23 (12-80) months for severe active luminal (70%), fistulating perianal (25.5%) and other fistulating disease (4.5%). Relapse rates at 90,180 and 365days were 4.7%, 18.6% and 36%, respectively. If anti-TNF dose escalation occurred 6months prior to withdrawal, 88% (7/8) relapsed. Based on multivariate analysis, risk factors for relapse include ileocolonic disease at diagnosis and previous anti-TNF therapy. An elevated faecal calprotectin (FC) is likely to predict relapse (p=0.02), with a PPV of 66.7% at >50μg/g. Of 36 patients who relapsed, 31 were retreated with anti-TNF, with an overall recapture rate of 93%.

CONCLUSION

Relapse rates at 1year following elective withdrawal of anti-TNF are 36%, with high retreatment response rate. Predictors of relapse include ileocolonic involvement, previous anti-TNF therapy and raised FC. Endoscopic/radiologic assessment prior to cessation of therapy does not appear to predict those at lower risk of relapse.

Discontinuation of Scheduled Infliximab in Crohn's Patients With Clinical Remission: A Retrospective Single-Center Study

Background

It is crucial to determine whether infliximab (IFX) therapy could be safely interrupted in Crohn’s disease (CD) patients with clinical remission. The outcome and risk predictors of relapse after IFX therapy stopped are controversial. The aim was to assess the relapse and predictive factors after IFX discontinuation in CD patients with clinical remission.

Methods

A retrospective cohort of CD patients with clinical remission who discontinued scheduled IFX therapy at Nanfang Hospital were included. The primary outcome was relapse. All patients were followed up for more than 3 months. Demographic, clinical, and laboratory parameters were evaluated for their predictive value of relapse.

Results

After a median follow-up period of 12.2(4.8 - 21.2) months, 55.7% (59/106) patients experienced a relapse. The cumulative relapse rate was 39%, 48% and 61% at 6 months, 1 year and 2 years, respectively. Based on multivariable analysis, CD-related surgery before infusion (P = 0.013, hazard ratio (HR): 2.671, 95% confidential interval (CI): 1.230 - 5.798), step-up therapeutic regimen (P = 0.035, HR: 2.073, 95%CI: 1.054 - 4.080), low albumin (Alb) level at week 0 (P = 0.022, HR: 3.431, 95%CI: 1.196 - 9.846) and high C-reactive protein (CRP) level at week 30 (P = 0.007, HR: 2.643, 95%CI: 1.310 - 5.332) were associated with clinical relapse.

Conclusions

After cessation of scheduled IFX therapy in CD patients with clinical remission, nearly half of the patients experienced a relapse within 1 year. In the event of the presence of certain predictive factors, IFX scheduled therapy should probably be continued.

Perioperative use of immunosuppressive medications in patients with Crohn's disease in the new "biological era"

Crohn’s disease (CD) is characterized by transmural inflammation of the gastrointestinal tract leading to inflammatory, stricturing and/or and fistulizing disease. Once a patient develops medically refractory disease, mechanical obstruction, fistulizing disease or perforation, surgery is indicated. Unfortunately, surgery is not curative in most cases, underscoring the importance of bowel preservation and adequate perioperative medical management. As many of the medications used to treat CD are immunosuppressive, the concern for postoperative infectious complications and anastomotic healing are particularly concerning; these concerns have to be balanced with preventing and treating residual or recurrent disease. We herein review the available literature and make recommendations regarding the preoperative, perioperative and postoperative administration of immunosuppressive medications in the current era of biological therapy for CD. Standardized algorithms for perioperative medical management would greatly assist future research for optimizing surgical outcomes and preventing disease recurrence in the future.

Is there a role of magnetic resonance imaging in deciding to stop anti-tumor necrosis factor treatment in ileal Crohn's disease?

PURPOSE

This study was performed to assess the ability of magnetic resonance enterography to predict the evolution of patients in whom anti-tumor necrosis factor-α therapy was suspended.

METHODS

A prospective study of patients with ileal Crohn's disease was performed.

RESULTS

Twenty-nine patients were included. Patients who later relapsed showed higher magnetic resonance scores than those who did not relapse (4.2 vs. 2.5, respectively; p<0.02). The area under the receiving-operating characteristics curve was 0.755 when discriminating patients who relapsed.

CONCLUSIONS

Magnetic resonance enterography should be taken into account when deciding the withdrawal of anti-tumor necrosis factor-α in patients with Crohn's disease.

Long-term outcome of inflammatory bowel disease patients with deep remission after discontinuation of TNFα-blocking agents

BACKGROUND

Little data exist on the long-term prognosis of patients with inflammatory bowel disease (IBD) after stopping TNFα-blocking therapy in deep remission. Existing data indicate that approximately 50% of patients on combination therapy who discontinued TNFα-blockers are still in remission 24 months later. The aims of this follow-up analysis were to evaluate the long-term remission rate after cessation of TNFα-blocking therapy, the predicting factors of a relapse and the response to restarting TNFα blockers.

METHODS

The first follow-up data of 51 IBD patients (17 Crohn's disease [CD], 30 ulcerative colitis [UC] and four inflammatory bowel disease type unclassified [IBDU]) in deep remission at the time of cessation of TNFα-blocking therapy have been published earlier. The long-term data was collected retrospectively after the first follow-up year to evaluate the remission rate and risk factors for the relapse after a median of 36 months.

RESULTS

After the first relapse-free year, 14 out of the remaining 34 IBD patients relapsed (41%; 5/12 [42%] CD and 9/22 [41%] UC/IBDU). Univariate analysis indicated no associations with any predictive factors. Re-treatment was effective in 90% (26/29) of patients.

CONCLUSION

Of IBD patients in deep remission at the time of cessation of TNFα-blocking therapy, up to 60% experience a clinical or endoscopic relapse after a median follow-up time of 36 months (95% CI 31-41 months). No individual risk factors predicting relapse could be identified. However, the initial response to a restart of TNFα-blockers seems to be effective and well tolerated.

Practical Approaches to "Top-Down" Therapies for Crohn's Disease

Crohn's disease (CD) is a chronic, progressive, and disabling disease that leads in most cases to the development of bowel damage presenting as a fistula, abscess, or stricture. For years, therapy for Crohn's disease has been based on a "step-up" approach, in which anti-TNF agents are administered after the failure of steroids and immunosuppressants. However, recent studies have suggested that early introduction of anti-TNF agents combined with immunosuppressants can modify the natural history of the disease. Patients who could benefit more of this "top-down" strategy would be those at elevated risk of a complicated or severe inflammatory bowel disease or with factors that can predict an aggressive disease course. Therefore, the management of a patient with CD should be personalized, taking into account the patient's specific characteristics and comorbidities, disease activity, site and behavior of the disease, and predictable factors of poor prognosis. A balance between medication and potential adverse effects should be achieved, trying to avoid under or overtreatment, always discussing the different therapeutic options with the patient. The natural history of ulcerative colitis differs from CD and, to date, there is not much scientific evidence on the use of early combined immunosuppression.

Repeated intensified infliximab induction - results from an 11-year prospective study of ulcerative colitis using a novel treatment algorithm

BACKGROUND

Anti-tumour necrosis factor (TNF) agents play a pivotal role in the treatment of moderate to severe ulcerative colitis (UC), and yet, no international consensus on when to discontinue therapy exists.

OBJECTIVE

The aim of this study is to study the long-term performance of a treatment algorithm of repeated intensified induction therapy with infliximab (IFX) to remission, followed by discontinuation in patients with UC.

PATIENTS AND METHODS

Patients with moderate to severe UC were enroled in an open prospective study design. The following algorithm was implemented: (a) intensified induction treatment to remission (Ulcerative Colitis Disease Activity Index score 0-2); (b) discontinuation of IFX; and (c) reinduction treatment if relapse. Mucosal gene expression for TNF was measured with qPCR.

RESULTS

A total of 116 patients were included. The median observation time was 47 and 51 months in intention to treat and per protocol. Remission rates of the first three inductions were 95, 93 and 91% per protocol and 83, 56 and 59% by intention to treat. The median time in remission was 40 months per protocol and 34 months by intention to treat. Long-term remission without further anti-TNF treatment during the observation period was obtained for 41%, with a median observation time of 48 months (range: 18-129 months). The median time to relapse was 33 and 11 months with/without normalization of mucosal TNF, respectively. The 5-year success rate for maintaining the effect of IFX in the algorithm was 66%.

CONCLUSION

The treatment algorithm is highly effective for achieving long-term clinical remission in UC. Normalization of mucosal TNF gene expression predicts long-term remission upon discontinuation of IFX.

Evolution After Anti-TNF Discontinuation in Patients With Inflammatory Bowel Disease: A Multicenter Long-Term Follow-Up Study

OBJECTIVES

The aims of this study were to assess the risk of relapse after discontinuation of anti-tumor necrosis factor (anti-TNF) drugs in patients with inflammatory bowel disease (IBD), to identify the factors associated with relapse, and to evaluate the overcome after retreatment with the same anti-TNF in those who relapsed.

METHODS

This was a retrospective, observational, multicenter study. IBD patients who had been treated with anti-TNFs and in whom these drugs were discontinued after clinical remission was achieved were included.

RESULTS

A total of 1,055 patients were included. The incidence rate of relapse was 19% and 17% per patient-year in Crohn's disease and ulcerative colitis patients, respectively. In both Crohn's disease and ulcerative colitis patients in deep remission, the incidence rate of relapse was 19% per patient-year. The treatment with adalimumab vs. infliximab (hazard ratio (HR)=1.29; 95% confidence interval (CI)=1.01-1.66), elective discontinuation of anti-TNFs (HR=1.90; 95% CI=1.07-3.37) or discontinuation because of adverse events (HR=2.33; 95% CI=1.27-2.02) vs. a top-down strategy, colonic localization (HR=1.51; 95% CI=1.13-2.02) vs. ileal, and stricturing behavior (HR=1.5; 95% CI=1.09-2.05) vs. inflammatory were associated with a higher risk of relapse in Crohn's disease patients, whereas treatment with immunomodulators after discontinuation (HR=0.67; 95% CI=0.51-0.87) and age (HR=0.98; 95% CI=0.97-0.99) were protective factors. None of the factors were predictive in ulcerative colitis patients. Retreatment of relapse with the same anti-TNF was effective (80% responded) and safe.

CONCLUSIONS

The incidence rate of inflammatory bowel disease relapse after anti-TNF discontinuation is relevant. Some predictive factors of relapse after anti-TNF withdrawal have been identified. Retreatment with the same anti-TNF drug was effective and safe.

Bovine lactoferrin and Crohn's disease: a case study

A 22-year-old male suffering from abdominal pain, repeated diarrhea, and weight loss visited the Digestive Disease Department of Nagoya City University Hospital on 19 December 2011. He was hospitalized and diagnosed with Crohn's colitis. His Crohn's Disease Activity Index (CDAI) was 415. Treatment by granulocyte apheresis, mesalazine, and adalimumab was started. His CDAI was 314 on 30 December and 215 on 5 January. A colonoscopic examination on 19 January showed almost complete remission in the transverse colon and marked remission in the rectum. Mesalazine therapy was stopped on 28 February, and the patient was instructed to self-inject 40 mg of adalimumab every other week. His CDAI was 50 on 10 April, indicating clinical remission. His last self-injection of adalimumab was on 24 April 2012, and he started taking 1 g of bovine lactoferrin (bLF) daily. His CDAI was 35 on 8 January 2013. He continued taking 1 g of bLF daily without any other treatment for Crohn's disease. Laboratory blood tests on 7 September 2015 showed no sign of disease recurrence, and a colonoscopic examination on 23 October 2015 showed almost complete mucosal healing. This case indicates that ingestion of bLF to maintain Crohn's disease in a remissive state should be further explored.

Discontinuation of anti-tumor necrosis factor therapy in inflammatory bowel disease patients: a prospective observation

BACKGROUND

Discontinuation of anti-TNF therapy in patients with inflammatory bowel diseases (IBD) in remission remains a controversial issue. The aims of our study were to assess the proportion of patients who relapse after cessation of biological treatment, and to identify potential risk factors of disease relapse.

METHODS

Consecutive IBD patients who discontinued anti-TNF therapy in steroid-free clinical and endoscopic remission were prospectively followed. Multiple logistic regression and Cox proportional-hazards models were used to assess the predictors of disease relapse.

RESULTS

Seventy-eight IBD patients (Crohn's disease, CD 61; ulcerative colitis, UC 17) were included and followed for a median of 30 months (range 7-47). A total of 32 (53%) CD patients and nine (53%) UC patients relapsed by the end of the follow-up with a median time to relapse of 8 months (range 1-25) in CD patients and 14 months (range 4-37) in UC patients, respectively. The cumulative probabilities of maintaining remission at 6, 12, and 24 months were 82%, 59%, and 51% in CD patients, and 77%, 77%, and 64% in UC patients, respectively. Survival of CD patients who were in deep remission (clinical and endoscopic healing; faecal calprotectin <150 mg/kg; CRP ≤5 mg/l) was not better compared with those who did not fulfill these criteria. In multivariate models, only colonic CD protected patients from disease relapse.

CONCLUSIONS

Approximately half of the IBD patients relapsed within 2 years after anti-TNF discontinuation. In CD patients, no difference between those who were or were not in deep remission was found. Colonic localization protected patients from relapse.

Optimizing Treatment with TNF Inhibitors in Inflammatory Bowel Disease by Monitoring Drug Levels and Antidrug Antibodies

BACKGROUND

Biological tumor necrosis factor (TNF) inhibitors have revolutionized the treatment of inflammatory bowel disease and redefined treatment goals to include mucosal healing. Clinicians are faced with challenges such as inadequate responses, treatment failures, side effects, and high drug costs. The objective is to review optimization of anti-TNF therapy by use of personalized treatment strategies based on circulating drug levels and antidrug antibodies (Abs), i.e. therapeutic drug monitoring (TDM). Furthermore, to outline TDM-related pitfalls and their prevention.

METHODS

Literature review.

RESULTS

Circulating anti-TNF drug trough level is a marker for the pharmacokinetics (PK) of TNF inhibitors. Because of a number of factors, including antidrug antibodies, PK varies between and within patients across time leading to variable clinical outcomes. Differences in intestinal inflammatory phenotype influencing the pharmacodynamic (PD) responses to TNF inhibitors also affect treatment outcomes. As an alternative to handling anti-TNF-treated patients by empiric strategies, TDM identifies underlying PK and PD-related reasons for treatment failure and aids decision making to secure optimal clinical and economic outcomes. Although promising, evidence does not the support use of TDM to counteract treatment failure in quiescent disease. Use of TDM is challenged by methodological biases, difficulties related to differentiation between PK and PD problems, and temporal biases due to lack of chronology between changes in PK versus symptomatic and objective disease activity manifestations. Biases can be accommodated by knowledgeable interpretation of results obtained by validated assays with clinically established thresholds, and by repeated assessments over time using complimentary techniques.

CONCLUSIONS

TDM-guided anti-TNF therapy at treatment failure has been brought from bench to bedside.

Considerations, challenges and future of anti-TNF therapy in treating inflammatory bowel disease

INTRODUCTION

Crohn's disease (CD) and ulcerative colitis (UC) are chronic disabling conditions. Monoclonal antibody therapy directed against tumor necrosis factor-alpha (anti-TNF) has revolutionized the care of patients with inflammatory bowel disease (IBD).

AREAS COVERED

Considerations before starting anti-TNF therapy are highlighted: the best time to start with anti-TNF therapy, either alone or in combination with an immunomodulator, the choice of an anti-TNF agent and the contra-indications to anti-TNF therapy. Primary nonresponse and secondary loss of response are discussed. De-escalating therapy, the role of therapeutic drug monitoring and the use of biosimilars, are handled. Finally, the future directions of anti-TNF therapy are emphasized.

EXPERT OPINION

Anti-TNF therapy remains the cornerstone in the treatment of IBD. When initiating long-term therapy, safety and cost issues are of great importance. The therapeutic armamentarium in the treatment of IBD is rapidly growing. Therefore, the challenge is to optimize the use and refine the exact position of anti-TNF therapy in the near future, with personalized medicine as the ultimate goal.

The Risk of Relapse after Anti-TNF Discontinuation in Inflammatory Bowel Disease: Systematic Review and Meta-Analysis

OBJECTIVES

To perform a meta-analysis of the risk of relapse after discontinuation of anti-tumor necrosis factor (anti-TNF) therapy in patients with Crohn's disease (CD) and ulcerative colitis (UC), to evaluate risk factors for relapse, and to assess the response to retreatment with the same anti-TNF.

METHODS

Studies evaluating the incidence of relapse after anti-TNF discontinuation in patients with CD or UC who reached clinical remission with anti-TNFs were included. Bibliographies up to January 2015 were searched. Frequency of relapse after discontinuation of anti-TNF agents was determined; meta-analyses were performed using the inverse-variance method.

RESULTS

We included 27 studies (21 infliximab and 6 infliximab/adalimumab). The overall risk of relapse after discontinuation of anti-TNF therapy was 44% for CD (95% confidence interval (CI) 36-51%; I(2)=79%; 912 patients) and 38% for UC (23-52%; I(2)=82%; 266 patients). In CD, the relapse rate was 38% at 6 months after discontinuation (short term), 40% at 12 months (medium term), and 49% at >25 months (long term). In UC, 28% of patients relapsed at 12 months. In CD, when clinical remission was the only criterion for stopping anti-TNF therapy, the relapse rate after 1 year was 42%, which decreased to 26% when endoscopic remission was also required. Retreatment with the same anti-TNF induced remission again in 80% of cases (68-91%).

CONCLUSIONS

Approximately one-third of patients with inflammatory bowel disease in remission under anti-TNF treatment relapsed 1 year after discontinuation. This proportion increased to half in the long term. In CD patients, the risk of relapse was lower when the criterion for discontinuation was endoscopic remission and not only clinical remission. Response to retreatment with the same anti-TNF agent was favorable.

Anti-TNF Withdrawal in Inflammatory Bowel Disease

The introduction of the anti-tumor necrosis factorα agents (anti-TNFα) in clinical practice has greatly advanced the treatment of inflammatory bowel disease. The use of these medications results in durable remission in a subset of patients, preventing surgery and hospitalizations. However, there are some concerns about safety and costs associated with their long-term use. Therefore, anti-TNF withdrawal has emerged as an important consideration in clinical practice. Herein our goal was to discuss the available evidence about anti-TNFα discontinuation in IBD that could inform the clinician on the expected rates of relapse, the potential predictors of relapse, as well the response to re-treatment.

Normalization of mucosal tumor necrosis factor-α: A new criterion for discontinuing infliximab therapy in ulcerative colitis

BACKGROUND

Biological agents such as anti-tumor necrosis factor (TNF) induce remission in ulcerative colitis. There is however no consensus regarding the discontinuation of this treatment.

AIM

The aim of this study is to assess whether clinical parameters and mucosal cytokine mRNAs in healed colonic mucosa can predict long-term remission in ulcerative colitis following discontinuation of infliximab (IFX) therapy.

METHODS

The prospective Tromsø Inflammatory Bowel Disease (IBD) Study is based on an intensified induction treatment algorithm with IFX to achieve disease remission. Following clinical and endoscopic remission, IFX treatment was discontinued, and follow-up until relapse was performed. Patients who achieved clinical and endoscopic remission following an induction course of IFX were included. Expression levels of TNF alpha (TNF), interferon gamma (IFNG), interleukin (IL) 6 (IL6), IL17A, IL23, and transforming growth factor beta (TGFB) were quantified by real-time PCR in mucosal biopsies obtained at colonoscopy. Remission was defined as Ulcerative Colitis Disease Activity Index (UCDAI) below 3, and an endoscopic sub-score of 0-1. Relapse was defined as UCDAI score >3 and endoscopic sub-score >1. Mucosal cytokine transcript levels from 20 non-IBD patients with a normal colonoscopy served as control group.

RESULTS

Of the 45 patients included, twenty patients (44%) had normalized levels of mucosal TNF expression at the time of mucosal healing, whereas 35 of 42 (83%) had normalized IL17A expression levels, and 31 of 36 (86%) had normalized IFNG expression levels. The median time to relapse was 8months (range 4-12). Normalization of TNF gene expression predicted 20months (1-39) relapse-free survival after withdrawal of IFX compared to 5months (3-7) in the group with elevated TNF expression. Mucosal expression levels of IL17A, IL23, IFNG, TGFB, IL6 did not predict long-term remission (>12months)

CONCLUSION

Normalization of mucosal TNF predicts long-term remission after discontinuation of IFX.

Low Dose Infliximab for Prevention of Postoperative Recurrence of Crohn's Disease: Long Term Follow-Up and Impact of Infliximab Trough Levels and Antibodies to Infliximab

Objective

In patients with postoperative recurrence of Crohn’s disease endoscopic and clinical remission can be maintained for up to 1 year with low infliximab doses (3 mg/Kg). However, in theory low-dose infliximab treated patients could develop subtherapeutic trough levels, infiximab antibodies, and might loose response to therapy. To verify this hypothesis infliximab pharmacokinetics and clinical/endoscopic response were checked in a group of patients treated in the long term with low infliximab doses.

Design

Infliximab antibodies, infliximab levels, highly-sensitive CRP and fecal calprotectin were measured during the 8-week interval in 5 consecutive patients in clinical (Crohn’s Disease Activity Index < 150) and endoscopic (Rutgeerts scores 0–1) remission after one year of therapy with infliximab 3 mg/Kg. For comparison with reported standards, infliximab pharmacokinetics and inflammatory parameters were also tested in 6 Crohn’s disease patients who did not undergo surgery and who were in clinical remission while on infliximab 5 mg/Kg. Patients on low infliximab dose also underwent colonoscopy after 18 additional months of therapy.

Results

Highly sensitive CRP and fecal calprotectin increased in all patients during the 8-week interval. Infliximab trough levels were lower in patients treated with the low dose compared to controls (mean±SE: 2.0±0.3 vs 4.75±0.83 μg/mL respectively p<0.05). Infliximab antibodies were present in two of the subjects treated with low infliximab dose and in none of the controls. However, in low dose-treated patients after 18 additional months of therapy endoscopy continued to show mucosal remission and none of them developed clinical recurrence or side effects.

Conclusions

Patients treated with low infliximab doses had lower trough levels compared to patients treated with 5 mg/Kg and some developed antibodies to infliximab. However, low infliximab doses sustained clinical and endoscopic remission for a total of 30 months of treatment.

Systematic Review of Effects of Withdrawal of Immunomodulators or Biologic Agents From Patients With Inflammatory Bowel Disease

Little is known about the optimal duration of therapy with an anti-tumor necrosis factor (TNF) agent and/or an immunomodulator for patients with inflammatory bowel disease (IBD). We performed a systematic search of the literature to identify studies reporting after de-escalation (drug cessation or dose reduction) of anti-TNF agents and/or immunomodulators in patients in remission from IBD. Studies were reviewed according to the type of IBD and drug. Rates of relapse, factors associated with relapse, and response to re-treatment were determined. Our search yielded 6315 unique citations; we analyzed findings from 69 studies (18 on de-escalation [drug cessation or dose reduction] of immunomodulator monotherapy, 8 on immunomodulator de-escalation from combination therapy, and 43 on de-escalation of anti-TNF agents, including 3 during pregnancy) comprising 4672 patients. Stopping immunomodulator monotherapy after a period of remission was associated with high rates of relapse in patients with Crohn's disease or ulcerative colitis (approximately 75% of patients experienced a relapse within 5 years after therapy was stopped). Most studies of patients with Crohn's disease who discontinued an immunomodulator after combination therapy found that rates of relapse did not differ from those of patients who continued taking the drug (55%-60% had disease relapse 24 months after they stopped taking the immunomodulator). The only study in patients with ulcerative colitis supported continued immunomodulator use. Approximately 50% of patients who discontinued anti-TNF agents after combination therapy maintained remission 24 months later, but the proportion in remission decreased with time. Markers of disease activity, poor prognostic factors, and complicated or relapsing disease course were associated with future relapse. In conclusion, based on a systematic review, 50% or more of patients with IBD who cease therapy have a disease relapse. Further studies are required to accurately identify subgroups of patients who are good candidates for discontinuation of treatment. The decision to withdraw a drug should be made for each individual based on patient preference, disease markers, consequences of relapse, safety, and cost.

Progress with anti-tumor necrosis factor therapeutics for the treatment of inflammatory bowel disease

Anti-tumor necrosis factor (TNF) therapy is a valid, effective and increasingly used option in inflammatory bowel disease management. Nevertheless, further knowledge and therapeutic indications regarding these drugs are still evolving. Anti-TNF therapy may be essential to achieve recently proposed end points, namely mucosal healing, prevention of bowel damage and prevention of patient's disability. Anti-TNF drugs are also suggested to be more effective in early disease, particularly in early Crohn's disease. Moreover, its efficacy for prevention of postoperative recurrence in Crohn's disease is still debated. Costs and adverse effects, the relevance of drug monitoring and the possibility of anti-TNF therapy withdrawal in selected patients are still debated issues. This review aimed to describe and discuss the most relevant data about the progress with anti-TNF therapy for the management of inflammatory bowel disease.

Higher Rates of Dose Optimisation for Infliximab Responders in Ulcerative Colitis than in Crohn's disease

BACKGROUND

Studies have demonstrated the benefit of dose optimisation in the setting of secondary loss of response to infliximab in inflammatory bowel disease.

AIM

The aim of our study was to retrospectively investigate the rates of dose optimisation in an inflammatory bowel disease cohort receiving maintenance infliximab therapy to determine if there are different rates of dose optimisation between CD and UC cases and what impact this has on the durability of treatment effect.

METHODS

Cases receiving infliximab for treatment of IBD between January 2008 and February 2014 were identified from an infusion centre database. Cases receiving ≥ 4 infusions were included in the study. Details of infusion dosing and timing were obtained. A dose increase from 5mg/kg to 10mg/kg or a reduction in the dosing interval was considered a dose optimisation.

RESULTS

A total of 412 cases were included in the study; 52.7% required at least one dose optimisation. Dose optimisation was more common in UC than in CD cases [67.2% vs 46.3%, p = 0.00006]. The median time to dose optimisation was 7 months (95% confidence interval [CI] 4.8-9.2) for UC cases and 27 months [95% CI 7.3-46.7] for CD cases, p = 0.00003.

CONCLUSIONS

Here we have shown that dose optimisation is required more frequently in UC than in CD, with a significantly shorter time to dose optimisation for UC cases than CD cases. The majority of cases responding to induction therapy with infliximab will have a sustained response to therapy, but over 50% will require a dose optimisation during their treatment.

Maintenance therapy for Crohn's disease: should it be indefinite?

Crohn's disease (CD) is a chronic, persistent, and destructive disorder with different forms of clinical behavior and the disease appears to be progressive over the long term. Providing greater levels of mucosal healing and resolution of clinical symptoms may modify the course of CD. This will often necessitate long-term therapy with immunosuppressant or biological therapies. Both these classes of drugs have side-effects and the latter are also very expensive. Identification of a subgroup of patients with a low risk of relapse and validation of the relevant predictors in various cohort studies are the key points to be able to cease immunosuppressant and/or biological therapy in patients with CD in stable remission. The individual parameters 'mucosal healing', 'deep remission', 'fecal calprotectin', and 'C-reactive protein' or various combinations of these parameters seem to be promising tools for predicting successful withdrawal of maintenance therapy.

Undetectable anti-TNF drug levels in patients with long-term remission predict successful drug withdrawal

BACKGROUND

Low drug levels are associated with emerging loss of response to anti-TNF. However, this may not be the case in patients with long-term remission.

AIM

To investigate the outcome of anti-TNF discontinuation in patients with long-term remission and incidental undetectable drug levels.

METHODS

A retrospective cohort study examining the duration of relapse-free survival in IBD patients in remission who discontinued infliximab or adalimumab having undetectable drug levels.

RESULTS

Forty eight patients who discontinued anti-TNF while in remission and had available drug levels were identified in two centres in France and Israel (infliximab-treated 35, adalimumab-13, Crohn's disease 30, ulcerative colitis 18, mean treatment duration of 22.7 ± 12.4 months). Endoscopy/MRE before stopping showed absence of active inflammation in 40/42 (95%) of evaluated patients, while inflammatory biomarkers (CRP and/or Calprotectin) were completely normal in only 31/48 (65%) of patients. During 12 months median follow-up, relapse occurred in 16/20 (80%) of patients who stopped anti-TNF while having measurable drug levels compared with 9/28 (32%) of patients who had undetectable drug levels (OR: 8.4, 95% CI: 2.2-32, P = 0.002). Relapse-free survival after anti-TNF cessation was significantly longer in patients with absent drug compared to those with detectable drug (P < 0.001, log rank test). On multivariate analysis, a patient's decision to stop therapy was weakly associated and abnormal inflammatory biomarkers and detectable drug levels were both strongly and independently associated with a higher risk of relapse after drug discontinuation.

CONCLUSION

Incidental finding of undetectable anti-TNF drug levels in patients with stable long-term deep remission may identify a subset of patients whose clinical remission is no longer dependent on anti-TNF treatment.

Systematic review: factors associated with relapse of inflammatory bowel disease after discontinuation of anti-TNF therapy

BACKGROUND

The discontinuation of anti-tumour necrosis factor (anti-TNF) treatment in inflammatory bowel disease (IBD) patients in remission could be considered.

AIM

To evaluate the factors associated with relapse of IBD after discontinuation of anti-TNF therapy.

METHODS

Electronic (PubMed/Embase) and manual search up to January 2015.

RESULTS

The overall risk of relapse after discontinuation of anti-TNFs (27 studies) was 44% for Crohn's disease (CD; follow-up range: 6-125 months) and 38% for ulcerative colitis (follow-up range: 6-24 months). Several factors were investigated to identify patients who are more likely to achieve long-lasting remission after anti-TNF discontinuation. The factors associated with a higher risk of relapse are younger age, smoking, longer disease duration, and fistulising perianal CD. Laboratory markers such as low haemoglobin levels, high C-reactive protein levels and high faecal calprotectin seem to increase the risk of relapse. On the other hand, low serum anti-TNF levels seem to be associated with a lower risk of flare-up. Mucosal healing seems to decrease the risk of relapse after anti-TNF discontinuation (overall, this risk is 26% at 1 year with mucosal healing and 42% without), although this observation has not been confirmed by some authors. In patients receiving escalated anti-TNF doses or receiving anti-TNFs for the prevention of post-operative CD recurrence, the risk of relapse after discontinuation is high (>75%). Re-administration of the drug in those who relapsed after stopping treatment is effective and safe.

CONCLUSIONS

A high proportion of patients with IBD relapse after discontinuation of anti-TNF treatment. As available data are insufficient to make strong recommendations on when anti-TNF therapy could be stopped, decisions should be taken on an individual basis.

Optimal Endpoint of Therapy in IBD: An Update on Factors Determining a Successful Drug Withdrawal

Ulcerative colitis (UC) and Crohn's disease (CD) are chronic inflammatory disorders, which require long term treatment to achieve remission and to prevent relapses and cancer. While current therapies are effective in most cases, they can have rare but serious side effects and are often associated with high costs. On the other hand, early discontinuation of an effective treatment may lead to a quick relapse and to complications at the restart of therapy. Therefore it is essential to determine the optimal duration of maintenance therapy, but clear guidelines are missing. The most important questions when deciding whether to continue or withdraw therapy in quiescent UC and CD patients are the efficacy of the continuous treatment to maintain remission in the long term, the frequency and severity of side effects, and the chance of relapse after discontinuation of therapy. This review summarizes the current knowledge on these topics with respect to 5-aminosalicylates, thiopurines, methotrexate, and biological therapies and collects information regarding when and in which specific patient groups, in the absence of risk factors, can withdrawal of therapy be considered without a high risk of relapse. Additionally, the particular aspect of colorectal cancer prevention by current therapies will also be discussed.

Long-term outcome of patients with Crohn's disease who discontinued infliximab therapy upon clinical remission

BACKGROUND & AIMS

There are limited data on the effects of discontinuing infliximab therapy for Crohn's disease (CD). We investigated the long-term outcome of patients with CD who discontinued infliximab while in clinical remission, and searched for prognostic markers of continued remission after infliximab cessation.

METHODS

We performed a retrospective, single-center study of 100 patients with CD who discontinued infliximab upon achieving clinical remission; 84 patients continued immunomodulator therapy. Clinical and endoscopic data were retrieved from a medical database in Belgium, and patients were followed up through April 2013 (median, 9.7 y; interquartile range, 8-11.5 y). Sustained clinical remission (SCR) was defined as maintenance of disease remission, without escalation in medical therapy or CD-related surgeries, until the end of the follow-up period. We measured trough concentrations of infliximab, antibodies to microbial antigens, and circulating inflammatory markers in serum samples collected before treatment and at the time of infliximab discontinuation.

RESULTS

At the end of the follow-up period, 52 patients had SCR. Univariate (log-rank) analysis associated SCR with patient age at diagnosis (≥25 y; P = .012) and disease duration (<1 y; P = .017). Among factors evaluated at the time of infliximab discontinuation, infliximab trough concentrations (<6 μg/mL; P = .031), complete mucosal healing (P = .046), and serum positivity for vascular cell adhesion molecule-1 (>0.67 μg/mL; P = .024) were associated with SCR. In multiple Cox proportional hazards regression analysis, only age at diagnosis of 25 years and older was associated independently with SCR (hazard ratio, 1.83; 95% confidence interval, 1.03-3.25; P = .04).

CONCLUSIONS

In a large, real-life study, 52% of patients with CD who discontinued infliximab upon achieving clinical remission remained in SCR after a median period of approximately 10 years; Most patients remained on immunomodulator therapy. Although patients with CD have variable responses to infliximab, a subgroup achieved long-term remission after infliximab discontinuation.

From historical perspectives to modern therapy: a review of current and future biological treatments for Crohn's disease

Crohn's disease (CD) is a debilitating, systemic inflammatory disorder with both gastrointestinal and extraintestinal manifestations. Its existence predates modern medicine, but its precise etiology remains incompletely understood. Most authorities suggest a multifactorial pathogenesis owing to a mixture of genetic disorders, immunologic dysregulation, microbiota disequilibrium and environmental influences. Of these factors, the overactive immunologic response seen in CD appears to be the most promising target of medical therapy. Biological agents comprise a relatively new class of drugs that can induce and maintain remission in moderate to severe CD, as well as in ulcerative colitis. This review will provide an overview of CD, its history, clinical features, pathophysiology, and treatment options focusing on current and future biological agents with an emphasis on drug development, dosage and administration.

Withdrawal of anti-tumour necrosis factor α therapy in inflammatory bowel disease

Anti-tumour necrosis factor α (anti-TNFα) therapy is an established treatment in inflammatory bowel disease. However, this treatment is associated with high costs and the possibility of severe adverse events representing a true challenge for patients, clinicians and health care systems. Consequently, a crucial question is raised namely if therapy can be stopped once remission is achieved and if so, how and in whom. Additionally, in a real-life clinical setting, discontinuation may also be considered for other reasons such as the patient’s preference, pregnancy, social reasons as moving to countries or continents with less access, or different local policy or reimbursement. In contrast to initiation of anti-TNFα therapy guidelines regarding stopping of this treatment are missing. As a result, the decision of discontinuation is still a challenging aspect in the use of anti-TNFα therapy. Currently this is typically based on an estimated, case-by-case, benefit-risk ratio. This editorial is intended to provide an overview of recent data on this topic and shed light on the proposed drug withdrawal strategies.

Mucosal healing in the era of biologic agents in treatment of inflammatory bowel disease

Mucosal healing has been a central issue in inflammatory bowel disease (IBD) for the last years, and has been proposed to be included as the new treatment goal in IBD. The molecular understanding of both the disruption and the healing of the intestinal epithelial cell lining and the mucosal barrier in IBD is complex and only partly understood. There is no general agreement on how to define healed mucosa, but there is a general acceptance that clinicians should use endoscopy and imaging technique in their assessments. Mucosal healing is an old concept that has been actualized in the present era of the highly effective biological agents. Randomized clinical studies with mucosal healing as end-point parameters have been reported, and early mucosal healing has been associated with low complication rates. We are waiting for documentation of whether treatment to healed mucosa can change the natural course of IBD. The concept of immunological remission has recently been introduced and can be the new treatment goal and one of several criteria for discontinuation of biological treatment in IBD. In conclusion, mucosal healing is a fairly novel concept and goal for biological treatment of IBD. There is a need for a standardization of its assessment and validation of the prognostic value.

Does fecal calprotectin predict short-term relapse after stopping TNFα-blocking agents in inflammatory bowel disease patients in deep remission?

BACKGROUND AND AIMS

This prospective multicenter study examined whether elevated fecal calprotec tin (FC) concentrations after stopping TNFα-blocking therapy can predict clinical or endoscopic relapse. In addition, we evaluated the impact of histological remission on the relapse risk.

METHODS

We enrolled inflammatory bowel disease (IBD) patients who were in clinical, endoscopic, and FC-based (< 100 μg/g) remission after a minimum 11 months of TNFα-blocking therapy. The patients were followed-up for 12 months after the discontinuation of TNFα-blocking therapy. FC was collected monthly for the first 6 months and thereafter every second month. Ileocolonoscopy was performed at inclusion, at 4 months, at the study end, and at the time of clinical relapse.

RESULTS

Of 52 enrolled patients, 49 (16 Crohn's disease, 33 ulcerative colitis/IBD unclassified) provided the stool samples requested and comprised the study group. During the follow-up, 15/49 (31%) relapsed, whereas 34 (69%) remained in remission. Patients relapsing showed constantly elevated FC levels for a median of 94 (13-317) days before the relapse. Significant increase in median FC levels was seen 2 (p = 0.0014), 4 (p = 0.0056), and 6 (p = 0.0029) months before endoscopic relapse. Constantly normal FC concentrations during the follow-up were highly predictive for clinical and endoscopic remission. Normal FC concentrations in patients with remission were associated with histological remission.

CONCLUSION

FC seems to increase and remain elevated before clinical or endoscopic relapse, suggesting that it can be used as a surrogate marker for predicting and identifying patients requiring close follow-up in clinical practice.

Consensus guidelines of ECCO/ESPGHAN on the medical management of pediatric Crohn's disease

Children and adolescents with Crohn's disease (CD) present often with a more complicated disease course compared to adult patients. In addition, the potential impact of CD on growth, pubertal and emotional development of patients underlines the need for a specific management strategy of pediatric-onset CD. To develop the first evidenced based and consensus driven guidelines for pediatric-onset CD an expert panel of 33 IBD specialists was formed after an open call within the European Crohn's and Colitis Organisation and the European Society of Pediatric Gastroenterolog, Hepatology and Nutrition. The aim was to base on a thorough review of existing evidence a state of the art guidance on the medical treatment and long term management of children and adolescents with CD, with individualized treatment algorithms based on a benefit-risk analysis according to different clinical scenarios. In children and adolescents who did not have finished their growth, exclusive enteral nutrition (EEN) is the induction therapy of first choice due to its excellent safety profile, preferable over corticosteroids, which are equipotential to induce remission. The majority of patients with pediatric-onset CD require immunomodulator based maintenance therapy. The experts discuss several factors potentially predictive for poor disease outcome (such as severe perianal fistulizing disease, severe stricturing/penetrating disease, severe growth retardation, panenteric disease, persistent severe disease despite adequate induction therapy), which may incite to an anti-TNF-based top down approach. These guidelines are intended to give practical (whenever possible evidence-based) answers to (pediatric) gastroenterologists who take care of children and adolescents with CD; they are not meant to be a rule or legal standard, since many different clinical scenario exist requiring treatment strategies not covered by or different from these guidelines.

Postoperative therapy with infliximab prevents long-term Crohn's disease recurrence

BACKGROUND & AIMS

A previous randomized, placebo-controlled study showed that infliximab maintenance therapy prevented recurrence of Crohn's disease 1 year after an ileocolonic resection. We evaluated recurrence of Crohn's disease, on the basis of endoscopic examination and/or the need for additional surgical resection, beyond the first postoperative year.

METHODS

In a prospective, open-label, long-term follow-up study, 24 patients previously randomly assigned to receive infliximab for 1 year after an ileocolonic resection were given the option to continue, stop, or start infliximab therapy. The primary end point was the time to recurrence of Crohn's disease, on the basis of endoscopic evidence (endoscopic recurrence), from the initial assignment to postoperative infliximab or placebo. Secondary end points were rate of endoscopic recurrence, time to reoperation, and rate of surgical recurrence in relation to the total time on infliximab.

RESULTS

All patients were followed for at least 5 years after surgery. Patients assigned to the infliximab group in the first year after surgery had a longer mean time to first endoscopic recurrence (1231 ± 747 days) than patients originally assigned to the placebo group (460 ± 121 days, P = .003). Colonoscopies identified Crohn's disease recurrence in 22.2% of patients who received long-term infliximab and in 93.9% of those not on infliximab (P < .0001). Compared with no infliximab, the adjusted rate ratio for being in endoscopic remission while on infliximab was 13.47 (95% confidence interval, 3.52-61.53; P = .0001). Patients originally assigned to the infliximab group had a mean longer time to surgery (1798 ± 359 days) than patients originally assigned to the placebo group (1058 ± 529 days, P = .04). The rate of surgical recurrence (required additional surgical resection) was significantly lower among patients who received infliximab for most of the follow-up period than patients who received it for shorter periods (20.0% vs 64.3%, P = .047).

CONCLUSIONS

Postoperative infliximab maintenance beyond 1 year prevents recurrence of Crohn's disease.

Review article: why, when and how to de-escalate therapy in inflammatory bowel diseases

BACKGROUND

Therapeutic objectives are currently evolving in inflammatory bowel diseases (IBD) from control of symptoms towards improvement of long-term disease outcomes. In patients achieving remission, safety concerns - infections or neoplasia - and economic issues are prompting de-escalation strategies.

AIM

To give a complete overview of studies on de-escalating therapy in IBD.

METHODS

A structured search in Pubmed, the Cochrane Library and EMBASE was performed using defined key words (inflammatory bowel diseases, Crohn's disease, ulcerative colitis, immunosuppressants, azathioprine, methotrexate, anti-TNF, infliximab, adalimumab, de-escalation, dose reduction, cessation, stopping, withdrawal), including full text articles and abstracts in English language.

RESULTS

Eleven studies were identified, investigating cessation of immunosuppressants (IS) and/or anti-TNF treatments. Patients exposed to a combination of IS and anti-TNF have an increased risk for infections, especially due to opportunistic agent, without any clear signal for associated cancers when compared to those receiving single therapy. In patients receiving IS alone, relapse rate at 12 months following IS cessation is close to 20% and 30% in Crohn's disease (CD) and ulcerative colitis (UC) respectively. There is no study specifically evaluating anti-TNF treatment withdrawal in case of scheduled anti-TNF monotherapy in IBD. In patients receiving combination therapy with IS and infliximab (IFX) for at least 6 months, relapse rate of IFX failure following IS cessation is near to 20% at 24 months and seems to be similar in patients who maintained combination therapy. In case of anti-TNF therapy, cessation in CD patients in combo-therapy proportion of relapse is high, close to 40% and 50% over 1 year and 2 years respectively. Regarding higher risk of adverse events, some special situations - young males, pregnancy and elderly - should be managed specifically and de-escalating treatment considered.

CONCLUSIONS

De-escalating treatment strategy should be mainly considered in patients with high risk of severe adverse events and low relapse risk (patients in deep remission) after drug withdrawal. For these reasons, cessation of anti-TNF treatment and/or immunosuppressants should be a case by case decision in highly selected patients.

Outcome after discontinuation of TNFα-blocking therapy in patients with inflammatory bowel disease in deep remission

BACKGROUND

Few data are available on the disease course in patients with inflammatory bowel disease (IBD) in deep remission after discontinuing tumor necrosis factor α (TNFα)-blocking therapy. In this prospective multicenter study, we evaluated the relapse rate, predictive factors, and the response to retreatment after discontinuation of TNFα-blocking therapy in patients with IBD in deep remission.

METHODS

We recruited 52 patients (17 Crohn's disease, 30 ulcerative colitis, and 5 IBD unclassified) in clinical, endoscopic, and fecal calprotectin-based (<100 μg/g) remission after at least 1 year of TNFα-blocking therapy. Clinical and endoscopic remission and relapse were defined according to validated indices. After discontinuation of therapy, the patients were followed up with endoscopic assessment at 4 and 12 months. In the event of a clinical relapse with endoscopically active disease or minor clinical symptoms but severe endoscopic relapse, TNFα-blocking therapy was restarted.

RESULTS

After a median follow-up time of 13 (range, 12-15) months, 17/51 (33%) patients relapsed (5/17 Crohn's disease, 12/34 ulcerative colitis/IBD unclassified, 1 patient lost to follow-up at 6 mo). Ten experienced clinical and endoscopic relapse, 5 clinical relapse with mild endoscopic activity, and 2 severe endoscopic relapse. No specific predictive factors were associated with the relapse. Retreatment was effective in 94% of patients.

CONCLUSIONS

After cessation of TNFα-blocking therapy in patients with IBD in deep remission, up to 67% remained in clinical remission during the 12-month follow-up. Importantly, 85% of these patients sustained endoscopic remission. The response to restart of TNFα antagonists was effective and well tolerated.

Tailoring anti-TNF therapy in IBD: drug levels and disease activity

The treatment of IBD with anti-TNF agents has substantially evolved since their first introduction more than a decade ago. The robust efficacy witnessed in many patients has raised new questions pertaining to the observation of subgroups of patients who fail to respond or who lose response to these otherwise very effective drugs. Conversely, the exorbitant cost of biologic agents coupled with their efficacy in inducing lasting remission has introduced new concepts addressing the possibility of therapy cessation in some patients after deep remission has been achieved. Measuring drug and anti-drug antibody (ADA) levels which develop in some patients has emerged as a valuable tool in understanding the mechanisms responsible for some of these clinical scenarios. However, knowledge on how to use these measurements to guide clinical decisions in daily practice is still in its nascency and awaits prospective validation trials. Furthermore, as described in this Review, knowledgeable interpretation of drug and ADA test results mandates understanding the interplay between the technical profile of the assay used, the timing of the measurement in the drug cycle, assessment of disease activity, and the profoundly different pharmaco-clinical scenarios that can culminate in a similar test result.