AB1186 THE NHS SCOTLAND THERAPEUTIC DRUG MONITORING SERVICE FOR BIOLOGIC MEDICINES: PRELIMINARY ANALYSIS OF UTILISATION AND CLINICAL RESULTS AT YEAR 1

Background:

Anti-tumour necrosis factor α (anti-TNFα) drugs infliximab (IFX) and adalimumab (ADL) are effective treatments for several rheumatic diseases. Therapeutic drug level and anti-drug antibody monitoring (TDM) has emerged as a useful tool for optimising drug effectiveness, by identifying individuals who may benefit from dose or treatment frequency adjustment, or have secondary drug failure due to immunogenicity.

Objectives:

Ensuring safe and effective use of biologic medicines has been identified as a key priority for NHS Scotland. Inequity and inconsistency of access to TDM across the nation was recognised as a barrier to delivering best practice and so a nationally commissioned TDM service was proposed in January 2018 to support clinical practice, providing universal access to TDM for services treating inflammatory diseases across Scotland. Data collection and analysis of results regarding usage and clinical impact of the service were identified as key outcome measures to assess service success and sustainability.

Methods:

A service webpage was developed to provide guidance on testing strategies and interpretation of TDM results (1). An automated search of clinical data and test results recorded within the clinical biochemistry electronic results management system was conducted to identify all TDM tests performed between 01/01/2018 and 31/12/2018. Descriptive analysis outcomes included the number of samples received, processed, overall testing population, service utilisation by Health Board, number and results of TDM tests performed per patient. TDM results were interpreted according to published guidance on the service webpage and comparison was made with previously published data (2).

Results:

3609 specimens were received for testing, from 13 of the 14 Scottish Health Boards. 3561 drug level (DL) tests were performed; 1786IFX, 1775 ADL. 2717 total antidrug anti-body (TABT) tests and 681 free antidrug anti-body tests (FABT) were performed according to service protocol. 2791 individuals had one or more TDM tests during the 12-month period, of whom 541 were tested twice or more (range 2-5).

Table 1.

IFX & ADL DL, TABT and FABT results by category as defined in service guidance (AU/ml = Arbitrary Units/ml)]

INFLIXIMABADALIMUMABDrug level by categorySupratherapeutic DL > 8mcg/ml546 (30.6%)708 (39.9%)Supratherapeutic DL > 10 mcg/mlTherapeutic DL ≥3<8.1mcg/ml738 (41.3%)636 (35.8%)Therapeutic DL ≥5<10.1 mcg/mlSub-therapeutic DL < 3mcg/ml502 (28.1%)431 (24.3%)Sub-therapeutic DL < 5 mcg/mlTABT by categoryNegative (<10 AU/ml)791 (54.2%)905 (71.9%)Negative (<10 AU/ml)Positive (>10 AU/ml)668 (45.8%)353 (28.1%)Positive (>10 AU/ml)FABT by categoryNegative (< 5AU/ml)376 (82.8%)176 (77.6%)Negative (<10 AU/ml)Positive (> 5 AU/ml)78 (17.2%)51 (22.4%)Positive (>10 AU/ml)

Conclusion:

TDM has been enthusiastically embraced. It is estimated that > 50% of individuals treated with IFX or ADL have been tested at least once in the first year. DL results were found to be similar to previously published data, as were rates of antibody positivity. The large volume of data generated by the service may provide additional evidence regarding the utility of TDM in predicting clinical response. Next steps are to conduct a comparative effectiveness analysis where proactive vs reactive TDM testing strategies will be compared, with the primary outcome measure being the proportions of patients with secondary loss of response.

References:

[1]Scottish Biologic therapeutic Drug Monitoring Servicehttps://www.nhsggc.org.uk/about-us/professional-support-sites/biochemistry/biological-therapy-monitoring/

[2]Jani, M. Et al (2015), Clinical Utility of Random Anti–Tumor Necrosis Factor Drug–Level Testing and Measurement of Antidrug Antibodies on the Long-Term Treatment Response in Rheumatoid Arthritis. Arthritis & Rheumatology, 67: 2011-2019. doi:10.1002/art.39169

Acknowledgments:

Biogen GmbH contributed partial funding for this research. Authors had full editorial control and approval of all content

Disclosure of Interests:

Jonathan MacDonald: None declared, Martin Perry Grant/research support from: Grifols, Abbvie, Sandoz unrestricted educational grant, Consultant of: Abbvie, Gilead, Celltrion Advisory Board, Speakers bureau: Sandoz, Peter Galloway: None declared, John-Paul Seenan: None declared, Alan Dunlop: None declared

Real-world Effectiveness and Safety of Vedolizumab for the Treatment of Inflammatory Bowel Disease: The Scottish Vedolizumab Cohort

BACKGROUND & AIMS

Vedolizumab is an anti-a4b7 monoclonal antibody that is licensed for the treatment of moderate to severe Crohn's disease and ulcerative colitis. The aims of this study were to establish the real-world effectiveness and safety of vedolizumab for the treatment of inflammatory bowel disease.

METHODS

This was a retrospective study involving seven NHS health boards in Scotland between June 2015 and November 2017. Inclusion criteria included: a diagnosis of ulcerative colitis or Crohn's disease with objective evidence of active inflammation at baseline (Harvey-Bradshaw Index[HBI] ≥5/Partial Mayo ≥2 plus C-reactive protein [CRP] >5 mg/L or faecal calprotectin ≥250 µg/g or inflammation on endoscopy/magnetic resonance imaging [MRI]); completion of induction; and at least one clinical follow-up by 12 months. Kaplan-Meier survival analysis was used to establish 12-month cumulative rates of clinical remission, mucosal healing, and deep remission [clinical remission plus mucosal healing]. Rates of serious adverse events were described quantitatively.

RESULTS

Our cohort consisted of 180 patients with ulcerative colitis and 260 with Crohn's disease. Combined median follow-up was 52 weeks (interquartile range [IQR] 26-52 weeks). In ulcerative colitis, 12-month cumulative rates of clinical remission, mucosal healing, and deep remission were 57.4%, 47.3%, and 38.5%, respectively. In Crohn's disease, 12-month cumulative rates of clinical remission, mucosal healing, and deep remission were 58.4%, 38.9%, and 28.3% respectively. The serious adverse event rate was 15.6 per 100 patient-years of follow-up.

CONCLUSIONS

Vedolizumab is a safe and effective treatment for achieving both clinical remission and mucosal healing in ulcerative colitis and Crohn's disease.

Are we exposing patients with a mildly elevated faecal calprotectin to unnecessary investigations?

OBJECTIVE

Faecal calprotectin (FC) is a non-invasive marker used to differentiate irritable bowel syndrome from inflammatory bowel disease (IBD). However, false positives are common. We sought to determine the diagnostic yield of investigation in patients presenting with new lower gastrointestinal (GI) symptoms and a mildly elevated FC (100-200 µg/g).

DESIGN

Retrospective study of electronic patient records.

PATIENTS

Patients aged 16-50 years with new lower GI symptoms and an FC 100-200 µg/g were identified from our biochemistry laboratory database between September 2009 and 2011. Patients were excluded if they had a previous FC >200 µg/g, were taking non-steroidal anti-inflammatory drugs (NSAIDs), had IBD, positive stool cultures or 'alarm' symptoms.

SETTING

Secondary care gastroenterology clinics.

RESULTS

161 patients (103 female patients) were identified. Mean age was 37.3 years with a mean FC of 147 µg/g. 398 endoscopic, radiological and histological investigations were undertaken in 141 patients (an average of 2.8 investigations per patient). 131 colonoscopies were performed with abnormalities in only 24 (18.3%). In patients with a macroscopically normal upper GI endoscopy and colonoscopy, the diagnostic yield of any further investigation was only 7.3%. The negative predictive value (NPV) of an FC 100-200 µg/g was 86.7% for any pathology and 97.5% for significant luminal pathology (IBD, advanced adenoma or colorectal carcinoma). After a mean follow-up of 172.4 weeks, IBD was the final diagnosis in only 4 (2.5%) of patients.

CONCLUSIONS

In adult patients under 50 years old presenting with new lower GI symptoms, the NPV of an FC between 100 and 200 µg/g in excluding significant organic GI disease is high.

High-resolution esophageal manometry: addressing thermal drift of the manoscan system

BACKGROUND

The high resolution esophageal manometry system manufactured by Sierra Scientific Instruments is widely used. The technology is liable to 'thermal drift', a change in measured pressure due to change in temperature. This study aims to characterize 'thermal drift' and minimize its impact.

METHODS

Response of the system to immediate temperature change (20 °C to 37 °C) was tested. Accuracy of pressure measurement over two hours at 37 °C was examined. Six repetitions were performed and median pressure change calculated for each sensor. Sensors were compared using Kruskal-Wallis test. Current correction processes were tested.

KEY RESULTS

There was a biphasic response of the system to body temperature: an immediate change in recorded pressure, 'thermal effect' and an ongoing pressure change with time, 'baseline drift'. Median thermal effect for all 36 sensors was 7 mmHg (IQR 3.8 mmHg). Median baseline drift was 11.1 mmHg (IQR 9.9 mmHg). Baseline drift varied between sensors but for a given sensor was linear. Interpolated thermal compensation, recommended for prolonged studies, corrects data assuming a linear drift of pressures. When pressures were corrected in this way, baseline pressure was almost restored to zero (Median 0.3 mmHg, IQR 0.3). The standard thermal compensation process did not address the error associated with baseline drift.

CONCLUSIONS & INFERENCES

Thermal effect is well compensated in the current operation of the system but baseline drift is not well recognized or addressed. Incorporation of a linear correction into current software would improve accuracy without impact on ease of use.

An unusual infection in an injecting drug user

Injecting drug users are prone to atypical infections. We present a case of septic thrombophlebitis secondary to Fusobacterium gonidiaformans infection in a heroin user, which demonstrates the frequently unusual nature of pathogens and presentations in this group of patients.

Paradox of gastric cardia: it becomes more acidic following meals while the rest of stomach becomes less acidic

INTRODUCTION

The proximal cardia region of the stomach has a high incidence of inflammation, metaplasia and neoplasia. It demonstrates less acid buffering following meals than the more distal stomach. Novel high definition pHmetry was employed to investigate acidity at the cardia under fasting conditions and in response to a meal.

METHODS

15 healthy subjects were studied. A custom-made 12-electrode pH catheter was clipped at the squamocolumnar junction with four electrodes recording proximal to and eight distal to the squamocolumnar junction. The most distal pH electrode was located at the catheter tip, and nine electrodes in the region of the squamocolumnar junction were 11 mm apart.

RESULTS

The electrode situated in the cardia 5.5 mm distal to the squamocolumnar junction differed from all other intragastric electrodes during fasting in recording minimal acidity (pH <4 = 2.2%) while all other intragastric electrodes recorded high intragastric acidity (pH <4 =or>39%) (p<0.05). The cardia also differed from the rest of the stomach, showing a marked increase in acidity in response to the meal (from 2.2% fasting to 58.4% at 60-70 min after the meal; p<0.05) while the electrodes distal to the cardia all showed a marked decrease in acidity (p<0.05). These changes in acidity at the cardia following the meal caused the gastric acidity to extend 10 mm closer to the squamocolumnar junction.

CONCLUSION

Whereas the rest of the stomach shows a marked fall in acidity on ingesting a meal, the cardia paradoxically increases in acidity to become the most acidic region throughout the postprandial period.