P711 A pilot study using point of care testing for infliximab and faecal calprotectin in IBD patients with a secondary loss of response

Abstract

Background: Therapeutic drug monitoring (TDM) and faecal calprotectin (FCP) testing in IBD patients with secondary loss of response (LOR) to infliximab (IFX), help guide clinicians to the most appropriate intervention to recapture response. However, TDM and FCP result reporting can be delayed, hampering immediate treatment optimisation. We investigated the clinical utility of TDM, FCP and resultant early dose optimisation, using rapid point-of-care (POC) testing. Method(s): Prospective inclusion of consecutive adults IBD patients accessed for secondary LOR to IFX. Results of testing for IFX through levels (TL) and FCP, measured by a POC device (BUHLMANN device Quantum BlueR), were compared with standard IFX TL, anti-IFX antibodies (ELISA, Progenika) and FCP (ELISA, ALPCO), measured through a central laboratory. Based on POC results, an algorithmic approach to TDM/FCP results was implemented (Table presented) Primary endpoint: proportion of patients in clinical remission at week 12, in those patients that underwent early treatment optimisation. Result(s): Seventeen patients were included (65% female, mean age: 37.1 +/- 17.4 years), CD n = 9 with mean HBI 6.33 +/- 1.5; UC n = 8 with mean partial Mayo 4.5 +/- 2.1. Mean duration of prior biological treatment was 28.1 months +/- 36.1. Mean IFX TL with POC testing was 14.5 +/- 6.6 and with standard testing was 16.8 +/- 7.9 (R=0.8, p = 0.001). Mean FCP level with POC testing was 472 +/- 332.7 and with standard testing was 489.9 +/- 630.5 (R=0.53, p = 0.04). 7/17 (41%) patients had low TL and high FC, 4/17 (24%)had adequate TL and high FCP and 6/17 (35%) had adequate TL and low FCP. In the 7 patients with low IFX trough and elevated FCP, treatment was modified (dose escalation/change therapy) in 5 (71%) and 4 out of 6 (67%) with available follow-up data from this group were in clinical remission at week 4 and 12. Using an algorithmic approach with POC TDM and FCP suggests that immediate dose optimisation would have resulted in an inappropriate management in 10/17 (59%) patients. Clinical remission data at week 12 were available in 13 patients and 10 (77%) were in clinical remission. (Table presented) Conclusion(s): Using POC testing for IFX patients with a secondary LOR is clinically useful, correlates well with standardised testing, allows for immediate appropriate management of patients with low IFX trough and high FCP and results in a rapid clinical remission as early as 4 weeks.