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Journal of Crohn's and Colitis: 10 (10)

Editor-in-Chief

Laurence J. Egan, Ireland

Associate Editors

Shomron Ben-Horin, IsraelSilvio Danese, ItalyPeter Lakatos, HungaryMiles Parkes, UKJesús Rivera-Nieves, USABritta Siegmund, GermanyGijs van den Brink, NLSéverine Vermeire, Belgium

6.585
5.586

Published on behalf of

Costs of adalimumab versus infliximab as first-line biological therapy for luminal Crohn's disease

Grace K.H. Choi, Stephanie D.E. Collins, Daniel P. Greer, Lisa Warren, Grace Dowson, Tanya Clark, P. John Hamlin, Alexander C. Ford
DOI: http://dx.doi.org/10.1016/j.crohns.2013.09.017 375-383 First published online: 1 May 2014

Abstract

Background and aims Randomised controlled trials demonstrate that the anti-tumour necrosis factor-α (anti-TNFα) therapies infliximab and adalimumab are effective in inducing remission and preventing relapse of Crohn's disease (CD). As few studies have compared costs and efficacy of these two drugs directly, we examined this issue.

Methods Data were collected for patients receiving either drug as first-line anti-TNFα for CD. Patients were matched as closely as possible on age, gender, weight, height, and date of commencement of therapy. Response to induction therapy was assessed at 12 weeks, and sustained clinical benefit at last point of follow-up. Resource data were collected for all patients until study end, with National Health Services reference costs applied to calculate the total cost per patient with adalimumab compared with infliximab.

Results Thirty-six patients had been treated with adalimumab as first-line anti-TNFα since 2010. We matched an identical number of infliximab patients. Demographic data were similar between the two groups. Costs were significantly lower with adalimumab (£6692.95 less per patient (95% confidence interval £1816.61–£11569.29)), which was largely driven by the drug costs and drug administration costs associated with infliximab. Twenty-nine (80.6%) patients responded to induction therapy with both drugs, and 22 (61.1%) achieved glucocorticosteroid-free sustained clinical benefit with either drug at last point of follow-up.

Conclusions Costs of infliximab used as first-line anti-TNFα therapy are greater, which may have implications for selection. Clinical outcomes appeared comparable, although power to detect a statistically significant difference would be limited.

Keywords
  • Crohn's disease
  • Adalimumab
  • Infliximab

1 Introduction

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract, of unknown aetiology, with a population prevalence of 130 to 200 per 100,000.13 There is no cure and the condition is chronic, with sufferers experiencing periodic relapses, or flare-ups, of disease activity. A significant number of patients may require immunomodulator therapy, with either thiopurines or methotrexate,49 but these drugs are not always effective or well-tolerated.

Adalimumab and infliximab are drugs that act against anti-tumour necrosis factor-α (TNFα), which have proven efficacy in CD. Randomised controlled trials (RCTs) consistently demonstrate that anti-TNFα agents are more effective than placebo for both induction and maintenance of remission in luminal CD,1016 and data from the SONIC trial have confirmed that infliximab is superior to azathioprine in terms of achievement of glucocorticosteroid-free remission.17 A recent meta-analysis reported that the number needed to treat (NNT) with these agents to induce remission was 8, and the NNT to maintain remission was 4.18

Despite their undisputed efficacy, these drugs have yet to be compared head-to-head in an RCT, so whether one is superior to the other is unclear. As a result, in the UK, the National Institute for Health and Care Excellence (NICE) recommend that either adalimumab or infliximab can be used as first-line anti-TNFα therapy,19,20 with the proviso that treatment should normally be started with the less expensive drug. The latter issue should take into account drug administration costs, the dose required, and the price per dose.

Recently, there have been two non-randomised studies that have compared treatment of CD with adalimumab and infliximab.21,22 Neither detected any meaningful differences in clinical efficacy between the two drugs, but no economic data were collected. In a retrospective study conducted in the USA there was a net cost saving with adalimumab,23 but to date there have been no UK studies published that have examined this issue. We have previously described our clinical and economic outcomes with infliximab used as first-line anti-TNFα therapy,24,25 as well as our clinical outcomes with adalimumab as second-line anti-TNFα therapy.26 We now report economic and clinical outcomes in patients treated with either adalimumab or infliximab as first-line anti-TNFα therapy in our centre, since the decision by NICE that either can be used first-line.

2 Methods

2.1 Participants and settings

The Leeds Teaching Hospitals Inflammatory Bowel Diseases (IBD) clinic has been treating luminal CD patients with infliximab as first-line anti-TNFα therapy since 2000, and either infliximab or adalimumab as first-line anti-TNFα therapy since 2010, following the publication of the NICE guidance in the UK. This is a large teaching hospital in a city in the North of England, with a population of approximately 800,000, which also receives tertiary referrals from other centres. We do not use certolizumab as a first-line anti-TNFα therapy in our centre. Patients selected to receive anti-TNFα therapies are usually glucocorticosteroid-resistant or dependent after failure of, or intolerance to, thiopurines and/or methotrexate. Choice of first-line anti-TNFα therapy is dictated by patient preference, as well as perceived likelihood of adherence with self-administered injections in the case of adalimumab. Therapeutic monitoring of anti-TNFα therapies, using antibodies to TNF and trough levels, or thiopurines, using thiopurine metabolite levels, were not available in our centre during the study period.

Once patients are initiated on treatment, they are monitored at regular intervals during therapy, by a team of specialist IBD nurses. Patients for this study were identified from a database of all luminal CD patients commenced on anti-TNFα therapy maintained by the IBD nurse specialists. Eligible patients were adults (aged 16 years and over) with a confirmed diagnosis of luminal CD according to endoscopic, histological, or radiological criteria, who had been commenced on anti-TNFα therapy at some point during their disease course.

All patients who had received adalimumab as first-line anti-TNFα therapy for luminal CD in our centre since 2010 were included in this study, which was a retrospective analysis of data, some of which was collected prospectively. Therapy with adalimumab was commenced as follows: 160 mg at week 0, followed by 80 mg at week 2, and then 40 mg every other week. The first two doses of adalimumab were administered by an IBD nurse specialist at a day case visit at the Leeds Immune Mediated Inflammatory Disorder Unit. At this time point the patients were assessed by the IBD nurse for suitability to self-administer adalimumab, in order to allow further therapy to be given in their own home. Need for dose escalation with adalimumab was defined as either an attempt to recapture response using one-off doses of 160 mg, followed by 80 mg, 2 weeks apart, or a decrease in dosage interval to 40 mg every week.

From a total number of 200 patients receiving infliximab as first-line anti-TNFα therapy for luminal CD during the same time period (2010 to the present), we matched an identical number as closely as possible to adalimumab patients based on age, gender, weight, height, and date of commencement of anti-TNFα therapy. Therapy with infliximab was commenced as follows: a 5 mg/kg infusion at 0, 2, and 6 weeks, followed by 8-weekly 5 mg/kg infusions thereafter. All infusions were administered as a day case visit at the Leeds Immune Mediated Inflammatory Disorder Unit. Dose escalation was defined as either an attempt to recapture response using a one-off 10 mg/kg infusion, or a decrease in infusion interval to 6-weekly. The relevant local research ethics committee in Leeds was approached, and confirmed that ethics approval was not required for this study.

2.2 Data collection

The following demographic data were collected: age at commencement of anti-TNFα therapy, weight (in kilogramme (kg)), gender, disease duration prior to commencement of anti-TNFα therapy, smoking status, the Montreal classification of disease (age at diagnosis, disease location and phenotype, and presence of perianal disease),27 a history of CD-related abdominal surgery, and presence of extra-intestinal manifestations of CD. We also collected data concerning concomitant immunomodulator prescription (azathioprine, mercaptopurine, methotrexate, or mycophenolate mofetil), concomitant glucocorticosteroid use at commencement of anti-TNFα therapy, duration of anti-TNFα therapy, total duration of follow-up, and reason for discontinuation of anti-TNFα therapy (primary non-response (defined as no response to induction therapy), secondary non-response (defined as relapse of disease activity following successful induction therapy), or adverse events).

2.3 Outcome measures used

Our primary aim was to examine the costs associated with each drug, when used first-line for the treatment of luminal Crohn's disease. Crohn's disease-related health services resource data were collected retrospectively from case notes and computer records for all patients until last point of follow-up after commencement of anti-TNFα therapy. These included inpatient admissions (medical or surgical), IBD-nurse led day case admissions for administration of infliximab infusions and adalimumab injections, outpatient clinic visits, telephone clinic consultations, surgical procedures (including intestinal resections and examinations under anaesthesia (EUAs)), endoscopic procedures (oesophagogastroduodenoscopy (OGD), colonoscopy, sigmoidoscopy and wireless capsule endoscopy), radiological investigations (plain X-ray, computed tomography (CT), and magnetic resonance imaging (MRI)), and number and total dose (in mg) of anti-TNFα infusions or injections. Where a patient switched to second-line anti-TNFα therapy, due to a failure or loss of response to first-line anti-TNFα therapy, all subsequent resource use, including outpatient clinic visits, investigations, operations, and number and total dose (in mg) of anti-TNFα infusions or injections, were classed as having been incurred with the first-line drug therapy. National Health Service reference costs for 2011 to 2012,28 and drug costs from the British National Formulary 2013,29 were applied to all these data (Table 1), in order to calculate the total CD-related health services cost per patient.

View this table:
Table 1

Unit costs used (in £UK) to obtain a total cost per patient.

Cost
Outpatient clinic visit£115
Telephone clinic£23
Attendance for infliximab infusion or adalimumab injection£365
Inpatient day£228
Surgical resection£2853
EUA£515
Plain X-ray£30
CT abdomen£105
MRI£169
OGD£453
Colonoscopy£570
Wireless capsule endoscopy£773
Flexible sigmoidoscopy£481
40 mg of adalimumab administered at day case visit£442
40 mg of adalimumab administered at homea£352
100 mg vial of infliximab administered at day case visit£446
  • a Value added tax not applied to adalimumab when administered in patient's own home.

Our secondary aim was to assess clinical outcomes with each drug. Response to adalimumab was documented prospectively at 12 weeks post-commencement of induction therapy. Response was defined by a decrease in Harvey-Bradshaw index (HBI) of ≥ 2 points from baseline, or using a physician's global assessment in those patients where HBI could not be recorded due to the presence of a stoma. Sustained clinical benefit with adalimumab during continuing therapy was defined by continued response to therapy, according to a physician's global assessment, at the last time point of follow-up.

Response to infliximab was determined prospectively at the same time point as adalimumab, and using the same criteria. Sustained clinical benefit with infliximab during continuing therapy, was defined using a decrease in HBI ≥ 2 points from baseline, or satisfying a physician's global assessment that continued benefit was achieved at the last point of follow-up, where HBI data were not available.

2.4 Statistical analysis

We compared all baseline demographics between patients receiving adalimumab and infliximab using a χ2 test for categorical data, and an independent samples t-test for continuous data, with a mean and standard deviation (SD). Dichotomous outcomes of interest were again compared between adalimumab and infliximab patients using a χ2 test. For cost data, we confirmed that these were approximately normally distributed using a histogram, and then compared costs between those receiving adalimumab and those prescribed infliximab using an independent samples t-test with a mean and SD. We calculated the mean difference in individual and total costs between adalimumab and infliximab used first-line, along with a 95% confidence interval (CI). All statistical analyses were performed using SPSS for Windows version 19.0 (SPSS Inc, Chicago, IL, USA).

3 Results

A total of 36 CD patients received adalimumab as first-line anti-TNFα therapy between 2010 and 2013. We selected 36 matched patients receiving infliximab as first-line-therapy during the same time period. Mean age of these 72 patients at diagnosis of CD was 28.4 years (range 3 to 60 years), and 35 (48.6%) were female. The mean duration of disease prior to initiation of first-line anti-TNFα therapy was 120 months (range 0 to 504 months). Demographic data and disease characteristics of adalimumab patients, compared with infliximab patients, are detailed in Table 2. Patients were well-matched, with no significant differences detected between the two groups. There were trends towards a longer duration of disease, higher rates of previous surgery, greater likelihood of being on glucocorticosteroids, and a larger proportion with extra-intestinal manifestations of disease among patients receiving adalimumab. A greater proportion of infliximab patients were co-prescribed an immunomodulator at commencement of anti-TNFα therapy. Duration of follow-up was almost identical between the two groups (19.3 months with adalimumab versus 20.5 months with infliximab).

View this table:
Table 2

Baseline characteristics and demographics of patients receiving adalimumab compared with infliximab.

Patients receiving adalimumab (n = 36)Patients receiving infliximab (n = 36)P value*
Age at diagnosis (SD)27.4 (12.8)29.6 (13.8)0.50
Age at commencement of anti-TNFα therapy (SD)39.4 (13.0)37.6 (13.1)0.56
Weight in kg (SD)74.8 (17.0)70.1 (14.8)0.22
Duration of disease in months prior to commencement of anti-TNFα therapy (SD)138.8 (150.0)98.6 (101.2)0.20
Duration of follow-up in months (SD)19.3 (10.3)20.5 (10.2)0.61
Duration of therapy in months (SD)14.8 (9.3)16.3 (11.1)0.51
Female (%)17 (47.2)18 (50.0)0.81
Smoker (%)9 (25.0)7 (19.4)0.57
Previous surgery (%)23 (63.9)15 (41.7)0.06
Co-prescribed immunomodulator at commencement of anti-TNFα therapy (%)13 (36.1)20 (55.6)0.10
Oral glucocorticosteroids at commencement of anti-TNFα therapy (%)22 (61.1)14 (38.9)0.06
Montreal age at diagnosis (%)
< 16 years5 (13.9)4 (11.1)0.67
17 to 40 years25 (69.4)23 (63.9)
> 40 years6 (16.7)9 (25.0)
Montreal extent (%)
Ileal10 (27.8)7 (19.4)0.17
Colonic7 (19.4)14 (38.9)
Ileocolonic19 (52.8)14 (38.9)
Montreal behaviour (%)
Non-stricturing, non-penetrating23 (63.9)21 (58.3)0.90
Stricturing5 (13.9)4 (11.1)
Penetrating8 (22.2)9 (25.0)
Perianal disease (%)6 (16.7)8 (22.2)0.55
Extra-intestinal manifestations (%)14 (38.9)7 (19.4)0.07
  • * P value for independent samples t-test for continuous data and Pearson χ2 for comparison of categorical data.

3.1 Costs of therapy

The costs of adalimumab therapy per patient, compared with infliximab, are provided in Table 3. Costs of outpatient appointments, inpatients days, surgery, and radiological and endoscopic investigations were all lower with infliximab, although none of these differences were statistically significant. However, drug costs and drug administration costs associated with anti-TNFα therapy were almost £8000 less per patient among those receiving adalimumab, which was highly statistically significant (P = 0.001). This difference led to a significant reduction in total costs of almost £7000 per patient in those receiving adalimumab (P = 0.008).

View this table:
Table 4

Clinical outcomes of patients receiving adalimumab compared with infliximab.

Patients receiving adalimumab (n = 36)Patients receiving infliximab (n = 36)P value*
Response to anti-TNFα therapy after induction therapy (%)29 (80.6)29 (80.6)1.0
Still on anti-TNFα therapy at last point of follow-up (%)26 (72.2)23 (63.9)0.45
Glucocorticosteroid-free sustained benefit at last point of follow-up (%)22 (61.1)22 (61.1)1.0
Glucocorticosteroid-free sustained benefit at last point of follow-up and no flares requiring prednisolone (%)15 (41.7)19 (52.8)0.35
Number of flares requiring prednisolone (%)
023 (63.9)32 (88.9)0.06
17 (19.4)3 (8.3)
25 (13.9)1 (2.8)
Needed dose escalation (%)5 (13.9)0 (0)0.02
  • * P value for Pearson χ2.

View this table:
Table 3

Costs incurred (in £UK) per patient receiving adalimumab compared with infliximab.

Patients receiving adalimumab (n = 36)Patients receiving infliximab (n = 36)P value*Mean difference in costs (95% CI)
Outpatient costs (SD)£789.23 (£553.37)£613.33 (£315.84)0.11−£175.90 (−£391.11 to £39.32)
Inpatient costs (SD)£970.63 (£2019.21)£563.67 (£1992.50)0.40−£406.96 (−£1356.99 to £543.07)
Surgery costs (SD)£681.54 (£1240.59)£388.53 (£1031.86)0.28−£293.02 (−£834.47 to £284.44)
Radiology costs (SD)£150.34 (£196.37)£135.56 (£135.19)0.71−£14.79 (−£95.03 to £65.46)
Endoscopy costs (SD)£339.03 (£633.68)£295.81 (£447.92)0.74−£43.22 (−£304.29 to £217.84)
Drug costs (SD)£15062.00 (£7044.07)£22861.63 (£11840.99)0.001£7799.63 (£3201.39 to £12397.87)
Total costs (SD)£18165.57 (£7963.57)£24858.52 (£12197.56)0.008£6692.95 (£1816.61 to £11569.29)
  • * P value for independent samples t-test.

3.2 Response to therapy

Response to induction therapy at 12 weeks was achieved in 29 (80.6%) of the 36 patients receiving adalimumab first-line (Table 4). A further five patients were judged as having partial response and continued the drug. One patient had primary non-response, and another patient discontinued the drug due to becoming pregnant (Fig. 1). Of the two patients who discontinued adalimumab at 12 weeks, the first commenced infliximab as second-line anti-TNFα therapy, and the patient who became pregnant restarted the drug. Both achieved sustained clinical benefit at last point of follow-up.

Figure 1

Flow of patients receiving adalimumab.

Again, among the 36 patients who received infliximab first-line, 29 (80.6%) responded to therapy (Table 4). A further three patients were judged as having partial response and continued the drug. One patient had primary non-response, and three patients discontinued the drug due to adverse events (Fig. 2). Two of these experienced an infusion reaction, and one developed a rash. Of the four patients who discontinued infliximab at 12 weeks, two went on to achieve sustained clinical benefit with adalimumab, and the other two had only recently commenced adalimumab, with response to therapy yet to be assessed.

Figure 2

Flow of patients receiving infliximab.

3.3 Glucocorticosteroid-free sustained clinical benefit at last point of follow-up

At the last point of follow-up (July 2013), 26 (72.2%) patients were still receiving adalimumab as first-line anti-TNFα therapy. Among the nine patients discontinuing adalimumab during maintenance therapy, five patients experienced secondary loss of response, two were well and discontinued the drug, one reported non-specific adverse events, and one discontinued the drug during an episode of depression (Fig. 1). Outcomes in these nine were as follows: two were well on a thiopurine, two were well on no medication, one was well on infliximab, one was waiting to commence infliximab, one had an infusion reaction with infliximab and had commenced certolizumab, and in the final two a definitive decision was pending.

There were 23 (63.9%) patients still on infliximab. Among the nine patients discontinuing infliximab during maintenance therapy three experienced secondary loss of response, three developed a skin rash, two became pregnant, and one reported non-specific adverse events (Fig. 2). Outcomes in these nine were as follows: three were well and in remission on adalimumab, three were on no anti-TNFα agent and were currently well, two were considering commencing adalimumab, and one was well on colestyramine for presumed bile acid diarrhoea.

In both the adalimumab and infliximab groups 22 (61.1%) of 36 patients achieved glucocorticosteroid-free sustained clinical benefit with the drug at last point of follow-up (Table 4). There were a total of 15 adalimumab patients who achieved glucocorticosteroid-free sustained clinical benefit, and who had not experienced any flare of disease activity requiring prednisolone during follow-up, compared with 19 infliximab patients (P = 0.35). Overall, 23 (63.9%) patients receiving adalimumab did not experience a flare of disease activity requiring prednisolone at any time point during follow-up, compared with 32 (88.9%) of those given infliximab (P = 0.06). There were five (13.8%) adalimumab patients who required dose escalation, compared with none of those receiving infliximab (P = 0.02). Mean weight among the five patients requiring dose escalation was considerably higher, compared with those who did not require dose escalation, although this was not statistically significant (88.6 kg versus 72.5, P = 0.20) the absolute difference may have contributed towards the need for dose escalation.

4 Discussion

This study has demonstrated that the costs associated with the dose and administration of anti-TNFα therapy were almost £8000 less per patient among those receiving adalimumab, and this led to a total cost saving of almost £7000 per patient treated. This was despite the fact that costs of outpatient appointments, inpatients days, surgery, and radiological and endoscopic investigations were all lower with infliximab, although none of these differences were statistically significant. Adalimumab and infliximab appeared to be of similar efficacy when used first-line in the treatment of Crohn's disease, although the study was not powered to detect a statistically significant difference in these outcomes. Identical numbers of patients responded to induction therapy, and achieved glucocorticosteroid-free sustained clinical benefit during maintenance therapy. However, there were trends towards a lower number of infliximab patients experiencing flares of disease activity that required treatment with prednisolone, and significantly more adalimumab patients required a dose escalation during maintenance therapy, which may have been driven by the fact that adalimumab is not weight-based.

Strengths of this study include the fact that we included data from all patients commenced on adalimumab as first-line anti-TNFα therapy for CD from a single centre. We also matched these to patients commenced on infliximab during the same time period according to age, gender, weight, height, and date of commencement of anti-TNFα therapy. This allowed us to compare the efficacy and costs of the two drugs among patients with very similar baseline demographic characteristics, during similar lengths of treatment and follow-up. Complete data were collected from initiation of therapy to either cessation, or last point of follow-up, for all patients, and we used the HBI to define response to both therapies at 12 weeks.

Limitations of the study include the retrospective nature of some of the data collected, and the fact that the outcomes of response to therapy at last point of follow-up were defined using a physician's assessment of sustained clinical benefit for the adalimumab patients, rather than a validated endpoint such as the HBI, which may have allowed a more precise measurement and stringent definition of response or remission. The study was not randomised, and although patients were well-matched on several key characteristics, those receiving adalimumab may have had more severe disease, as evidenced by a higher rate of prior need for surgery. However, if anything, this is likely to have led to an underestimate of the difference in costs between the two agents. The accuracy of data collection was also dependent on the quality and comprehensiveness of medical records. The number of patients included in the study was too small to detect any clinically meaningful differences in the efficacy of these two drugs when used as first-line anti-TNFα therapy in CD. As infliximab dosing is based on weight, and we did not monitor change in weight during therapy, there is the possibility that patients receiving infliximab who experienced disease remission may have gained weight, and hence the total amount of drug required at each infusion would have increased during follow-up. In addition, we routinely carry out vial sharing among patients receiving infliximab in our centre, meaning that we only applied costs per mg used, rather than per vial of the drug. These factors may have led us to underestimate the true costs associated with infliximab therapy in centres that do not carry out vial sharing. Finally, the study was conducted entirely in a single tertiary care centre, and patients were selected for anti-TNFα therapy based on NICE guidelines in the UK, meaning that the results may not be generalisable to patients receiving first-line anti-TNFα therapy in the secondary care setting or the community, or in countries where anti-TNFα therapy is used at an earlier point in the disease course.

The similar rates of response and sustained clinical benefit that we observed with the two drugs in this group of patients are comparable to those reported recently by others. In a retrospective study from the Netherlands, there were no significant differences in response to treatment at either 1 or 2 years in 100 patients treated with either drug as first-line anti-TNFα.22 A US cohort study conducted using a Medicare database, which contained over 2000 patients treated with either therapy first-line, demonstrated that an almost identical proportion of patients remained on adalimumab or infliximab at 6 months. Rates of hospitalisation and surgery were generally lower among those treated with infliximab, but these differences were not statistically significant. There has been only one study, to date, conducted in the US that has examined economic outcomes according to whether adalimumab or infliximab is used first-line.23 The authors reported that there was a cost saving of almost $5500 during the first 6 months of treatment with adalimumab, compared with infliximab, but the largest difference in costs observed in this study was for outpatient visits, which were fewer among those receiving adalimumab. As it is unlikely that head-to-head trials of these two agents will ever be conducted, and therefore the efficacy and cost-effectiveness of one therapy compared to the other remains unclear, this underlines the importance of data from these studies, and the current study, which are based in routine clinical practice.

Despite lower costs with adalimumab, there were more flares of disease activity requiring prednisolone, compared with patients receiving infliximab, and non-significant trends towards lower costs for outpatient visits, days spent as an inpatient, surgeries, and investigations with infliximab. It may be that if our sample size had been larger, these more subtle differences between the two therapies would have become statistically significant, and led to equivalence between the two drugs in terms of costs. In addition, significantly more patients receiving adalimumab required dose escalation, and the absolute difference in weight was greater among these individuals. A recent study confirmed in a large cohort of patients treated with adalimumab that higher body mass index predicted a need for dose escalation.30 As adalimumab is given at a standard dose, whilst infliximab is weight-based, it may be that there is a threshold weight at which one therapy should be preferred over the other, and this issue requires further study.

Despite recommendations in the UK that selection of first-line anti-TNFα therapy should be dictated by cost, we suspect that in many centres, including our own, ultimately the choice is based on patient preference and likelihood of adherence. Our data suggest that, at the present time, this could have significant cost implications for the health service. However, with biosimilar infliximabs on the horizon for the treatment of Crohn's disease, this may lead to a reduction in the costs of therapy relative to adalimumab and other available anti-TNFα therapies,31 although the European Crohn's and Colitis Organisation have recently produced a position statement addressing this issue, and recommend that biosimilars should demonstrate similar efficacy and safety to existing biological therapies before they are approved for use in IBD.32

In conclusion, we have demonstrated that costs of care for CD were significantly lower with adalimumab used as first-line anti-TNFα therapy, compared with infliximab, and this was entirely attributable to a combination of the weight-based dosing schedule for infliximab, as well as the requirement to attend hospital for the administration of infusions. This may have implications for choice of first-line anti-TNFα agent for CD in health services with a limited budget.

Conflict of interest

Grace K.H. Choi: none. Stephanie D. E. Collins: none. Daniel P. Greer: none. Lisa Warren: none. Grace Dowson: none. Tanya Clark: none. Dr P. John Hamlin has participated on advisory boards for Schering-Plough/MSD pharmaceuticals, Abbott Pharmaceuticals, and Otsuka. Dr. Alexander C. Ford has received speaker's fees from MSD and Shire pharmaceuticals.

Acknowledgements

Sources of Funding: None.

Contributors: None.

Statement of authorship: GKHC, SDEC, DPG, LW, GD, TC, PJH, and ACF conceived and drafted the study. GKHC, SDEC, DPG, LW, GD, and TC collected all data. GKHC, SDEC and ACF analysed and interpreted the data. ACF drafted the manuscript. All authors commented on drafts of the paper. All authors have approved the final draft of the manuscript.

Footnotes

  • 1 Joint first authorship.

Abbreviations
CD
Crohn's disease
CI
confidence interval
CT
computed tomography
EUA
examination under anaesthesia
HBI
Harvey-Bradshaw index
IBD
inflammatory bowel disease
kg
kilogramme
MRI
magnetic resonance imaging
NICE
National Institute for Health and Care Excellence
NNT
number needed to treat
OGD
oesophagogastroduodenoscopy
RCT
randomised controlled trial
SD
standard deviation
TNFα
tumour necrosis factor-α.

References

View Abstract