P428 Early and Late Fecal Calprotectin Remission - Analysis of a proactive Therapeutic Drug Monitoring Treatment Protocol

Abstract Background Fecal calprotectin (Fc) is an adequate surrogate marker for endoscopic activity in inflammatory bowel disease. The timing of Fc remission may have prognostic implications in patients under biologic therapy. Methods Using a prospectively maintained database we followed 135 patients under a proactive therapeutic drug monitoring (pTDM) protocol aiming at an Infliximab trough level (IFXTL) between 5-10 µg/mL with sequential measurements of Fc. We evaluated the rates of early (at week 14) and late (after week 14) Fc remission (<250 µg/g) and associated clinical outcomes at 2-years of follow up. Results 77 patients (57.0%) reached early Fc remission and 30 patients (22.2%) reached late Fc remission. Patients with late Fc remission presented higher Fc at baseline (1708.5 μg/g [681-3483] vs 803 μg/g [339-1477], P=0.006) and lower IFXTL at week 14 (2.71 µg/mL [1.24-6.30] vs 6.59 µg/mL [3.41-10.63], P=0.001) than patients with early Fc remission. However, by the end of follow-up, IFXTL were similar in both groups: 7.94 µg/mL (4.79-11.25) vs 8.54 µg/mL (6.49-11.07), P=0.514. In patients without early Fc remission, week 14 IFXTL did not differ between those with and without late Fc remission (2.71 µg/mL [1.24-6.30] vs 3.47 µg/mL [0.945-6.94], P=0.957), but significantly increased in late responders by the end of follow-up: 8.54 µg/mL (6.49-11.07) vs 4.37 µg/mL (1.77-7.49), P=0.002. Patients with early and late Fc remission presented similar rates of clinical remission (88.3% vs 83.0%, P=0.493), steroid-free clinical remission (79.1% vs 92.9% P=0.239), lower rates of IFX discontinuation (14.3% vs 16.7%, P=0.756), hospitalization (11.7% vs 13.3%, P=0.815), and surgery (1.3% vs 3.3%, P=0.485). Conclusion The magnitude of Fc at baseline and IFXTL at week 14 significantly influence the timing of Fc remission. The use of PTDM results in similar pharmacokinetics and clinical outcomes in both groups.

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P368 Proactive Therapeutic Drug Monitoring is more effective than Conventional Management in Inducing Fecal Calprotectin remission in Inflammatory Bowel Disease

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjab076.492 ◽

2021 ◽

Vol 15 (Supplement_1) ◽

pp. S386-S386

Author(s):

J Pedro ◽

I Rodrigues ◽

S Fernandes ◽

A R Gonçalves ◽

S Bernardo ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Therapeutic Drug Monitoring ◽

Clinical Outcomes ◽

Bowel Disease ◽

Drug Monitoring ◽

Clinical Remission ◽

Therapeutic Drug ◽

Conventional Management ◽

Inflammatory Bowel

Abstract Background Proactive therapeutic drug monitoring (pTDM) may potentially improve disease control and treatment outcomes in inflammatory bowel disease. Methods Using a prospectively maintained database we compared 135 patients following a pTDM protocol aiming at an Infliximab trough level (IFXTL) between 5-10 µg/mL with sequential measurements of Fc, with 108 patients from a retrospective group under conventional management (noTDM). We evaluated the rates of Fc remission (<250 µg/g), and other clinical outcomes at 2-years of follow up. Results pTDM associated with higher rates of Fc remission (69.6% vs 50.0%; P=0.002), and steroid-free clinical remission (78.4% vs 55.2%, P=0.028) with a trend for clinical remission (79.3% vs 68.5%, P=0.075). There was no difference in treatment discontinuation (P=0.195), hospitalization (P=0.156), and surgery (P=0.110). Higher IFXTL associated with Fc remission at week 14 (6.59 vs 2.96 µg/mL, P<0.001), and at the end follow-up (8.10 vs 5.03 μg/mL, P=0.001). Fc remission associated with higher rates of clinical remission (85.8% vs 56.8% P<0.001), steroid-free clinical remission (86.9% vs 50.0% P<0.001), and lower rates of IFX discontinuation (8.8% vs 36.8%, P<0.001), and hospitalization (13.5% vs 33.7%, P<0.001) with a non-significant trend for surgery (6.1% vs 12.6%, P=0.101). Conclusion PTDM was more effective than conventional management in inducing Fc remission which associated with improved clinical outcomes.

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P346 Single-centre experience of ustekinumab: Therapeutic drug monitoring in Crohn’s disease patients

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjz203.475 ◽

2020 ◽

Vol 14 (Supplement_1) ◽

pp. S331-S333

Author(s):

C Liefferinckx ◽

M Fassin ◽

D Thomas ◽

C Minsart ◽

A Cremer ◽

...

Keyword(s):

Crohn’S Disease ◽

Therapeutic Drug Monitoring ◽

Crohn's Disease ◽

Median Time ◽

Real World ◽

Drug Monitoring ◽

Drug Exposure ◽

Therapeutic Drug ◽

Loss Of Response

Abstract Background Therapeutic drug monitoring (TDM) is a diagnostic tool in the monitoring of anti-TNF therapies. Yet, the benefit for TDM of new biologics such as ustekinumab (USK) is still controversial in real-world experiences. Methods This monocentric retrospective study aims to correlate USK trough levels (TLs) with clinical and endoscopic data. All patients have given written consent to the Biobank (B2011/005). Endoscopic disease was defined as quiescent in absence of endoscopic lesions, mild disease in presence of few superficial ulcerations, moderate in presence of several ulcers and severe in presence of numerous deep ulcers and/or inflammatory stenosis. 313 serum USK samples from 67 Crohn’s disease patients were used to measure USK TL (USK ELISA, apDia) while 88 samples (at week 16, and before and after optimisation) were used to measure anti-drug antibody (ADA), using a drug-tolerant affinity capture elution anti-ustekinumab assay Results Demographic and baseline data of our population are presented in Table 1. The median follow-up was 73 weeks (IQR 39–92). An optimisation due to loss of response was required in 44.8% of patients (n = 30) after a median time of 38 weeks (IQR 24–55). To evaluate the drug efficacy, an endoscopy was performed in 61% of cases at a median time of 35 weeks (IQR 27–47). TLs were 5.2 µg/ml (IQR 2.1–8.8), 1.7 µg/ml (IQR 0.3–4.3) and 2.6 µg/ml (IQR 0.6–4.1) at week 8, 16 and 24, respectively. TLs at week 8 were correlated to the induction IV dose administrated (r = 0.3, p = 0.03). At week 16, low TLs were associated with higher endoscopic activity in the follow-up (p = 0.02), although this was not the case at week 8 (p = 0.5) (Figure 1). Patients not requiring an optimisation had higher TLs in maintenance than patients requiring optimisation (2.45 µg/ml (IQR 1.3–4.4) vs. 1.15 µg/ml (IQR 0.1–2.24), p = 0.008). Obviously, optimisation significantly increased TLs (1.15 µg/ml (IQR 0.1–2.24) vs. 6.6 µg/ml (IQR 2.3–11.3), p < 0.001). ADA were undetectable in all the measured samples in maintenance. Conclusion This real-world experience confirms a drug exposure-endoscopic response relationship. Week 16 seems to be an appropriate time point to monitor drug exposure. Earlier USK TLs, at week 8, appear less valuable to be monitored due to the influence of initial IV dose. The absence of immunogenicity suggests that it is not a key driver in the loss of response.

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P465 Therapeutic drug monitoring in Crohn’s disease patients, a comparison between homogeneous mobility shift assay and point of care method

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjz203.594 ◽

2020 ◽

Vol 14 (Supplement_1) ◽

pp. S412-S412

Author(s):

G Bodini ◽

M G Demarzo ◽

A Djahandideh ◽

I Baldissarro ◽

E Savarino ◽

...

Keyword(s):

Crohn’S Disease ◽

Therapeutic Drug Monitoring ◽

Crohn's Disease ◽

Drug Concentration ◽

Drug Monitoring ◽

Point Of Care ◽

Therapeutic Drug ◽

Serum Drug Concentration ◽

Disease Relapse

Abstract Background Therapeutic Drug Monitoring (TDM) is a useful tool to help physicians managing patients with Inflammatory Bowel Disease treated with anti-tumour necrosis factor (TNF) drugs. Different techniques are available to evaluate serum drug concentration (TL), However, these techniques are time-consuming. A point-of-care (POC) method has been proposed to evaluate drug TL and overcome the limitations inherent to other methodologies. Our aim was to evaluate the capability of POC to discriminate between IBD relapse and remission and to evaluate the concordance of drug TL measured with POC and HMSA Methods We analysed with Quantum BlueÒ (Buhlmann Laboratories AG, Schonenbuch, Switzerland) (POC) 200 Adalimumab (ADA) and 200 Infliximab serum samples of 46 Crohn’s disease (CD) patients previously assessed with HMSA. Blood samples were drawn at standardised time points during anti-TNF treatment (2, 6, and every 8 weeks), before anti-TNF administration. Disease activity was assessed by the Harvey–Bradshaw Index (HBI, remission defined by HBI<5). Results We evaluated 46 CD patients responders to anti-TNF induction with ADA (n = 25, 54.3%) and IFX (n = 21, 45.6%) with a median follow-up of 83 weeks (range 16–144 weeks). At week 16, median ADA TL of patients in remission were significantly higher as compared with patients in disease relapse using both HMSA [12.7 μg/ml (range, 8.9–23.6 μg/ml) vs. 6.6 μg/ml (range, 0.7–9.6 μg/ml), p = 0.0001] and POC [17.8 μg/ml (range 7.6–35.0 μg/ml) vs. 9.8 μg/ml (range 5.8–11.4 μg/ml), p = 0.0003]. The concordance between the two different techniques has been assessed as 0.76 by Choen Kappa. Considering IFX TL, patients in remission had higher serum drug concentration using both HMSA [7.0 μg/ml (range, 0.0–21.8 μg/ml)] and POC [6.2 μg/ml (range 0.4–14.3 μg/ml)] as compared with patients who experienced disease relapse [HMSA, 0.1 μg/ml (range, 0.0–4.1 μg/ml), p = 0.019; POC, 0.45 μg/ml (range 0.4–3.3 μg/ml), p = 0.0072]. The concordance between the two different test for IFX TL was 0.81. We obtained similar results at the end of follow-up: median ADA TL was higher in remission than in disease relapse patients using both HMSA and POC [p = 0.001 and p = 0.0012] with a concordance of 0.75. Median IFX TL was higher in remission than in disease relapse patients using both HMSA and POC (p = 0.13 and p = 0.25) with a concordance of 0.70. Conclusion Both POC and HMSA are TL tests able to differentiate relapse and remission in IBD patients. The association between anti-TNF TL and disease status (remission/relapse) was better in ADA-treated patients rather than patients treated with IFX. Finally, we demonstrated a good concordance between HMSA and POC. Anti-drug antibody concentrations while available on HMSA were not available on POC

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