P674 Monitoring posologic change in adalimumab intensification dosing regimen from 40 mg every week to 80 mg every other week

Abstract

Abstract Background The previous usual adalimumab (ADA) intensification regimen was 40 mg every week (ew)). Recently the original laboratory commercialised the 80 mg injection pen, with pharmacokinetic studies indicating an alternative intensification dose of 80 mg every other week (eow) similar to 40 mg ew, even though interchangeability has not been assessed in clinical practice. In the biosimilars era, this pen was sold to many Hospitals at the same price as the 40mg pen. For this fact and for patient comfort, we proposed our stable-intensificated-ADA IDB patients on a 40 mg ew regimen, to change the dose to 80 mg eow (clinical practice). Methods In this setting, we designed an observational study to monitor clinical, analytical and pharmacokinetic outcomes through this posologic change, for patients who signed the Informed Consent. Clinical (Harvey–Bradshaw index (HBI), partial Mayo score), analytic parameters and ADA trough levels were prospectively obtained at baseline, 4 and 8 months after posologic change. We describe the evolution of this cohort and calculate savings. Results 12 from 18 patients initially evaluated for new dose regimen were finally changed. All of them agreed to participate in the study. Eighty-three per cent were CD patients, 58% males, median age 51 years old (intecuartil range (IQR) 42–55). Median age at IBD diagnosis was 34 years (IQR 24–44). In 9 patients ADA was the first-line biologic. Median IBD duration before starting ADA was 6 years (IQR 5–8). Median time from ADA initiation to intensification was 31 months (IQR 14–55). The median time of ADA intensification was 37 months (IQR 30–66). Seventy per cent of patients were on immunosuppressors (IS) at the start of the study. Table 1 shows the results of clinical, analytical variables and ADA trough levels at baseline, 4 and 8 months. No differences were found. At 4 months, all patients maintained ADA 80 mg eow. Two patients referred mild worsening, (HBI from 3–4 to 5–6) without significant changes in CRP, calprotectin or ADA levels. They recovered after restoring the previous regimen (ADA 40mg ew). At 8 months, ADA was stopped in one patient in remission with undetectable ADA levels and positive ATI. Total savings in the first 8 months were 59022 €. Conclusion in IBD patients with stable response to ADA intensification regimen of 40 mg ew, changing to 80mg eow seems to maintain response and similar trough levels, although some patients may perceive mild symptoms. Economic savings are 50% per patient.