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P461 Vedolizumab Dose Escalation in a Real-World Cohort of IBD Patients

Zelinkova, Z.(1);Kadleckova, B.(1);Lucenicova, J.(2);

(1)St. Michael`s Hospital, Department of Gastroenterology&Digestive Endoscopy, Bratislava, Slovakia;(2)St. Michael`s Hospital, Department Clinical Biochemistry&Hematology, Bratislava, Slovakia

Background

Vedolizumab (VDZ) effectively induces and maintains remission in inflammatory bowel disease (IBD). The loss of response to VDZ has been shown to be recaptured with dose escalation but the data in this field are still scarce. In addition, data on pharmacokinetics (PK) of dose escalation are limited and it is unclear whether PK should used in decision-making algorithm in adjusting VDZ dose regimen. Therefore, the aim of our study was to assess clinical efficacy and pharmacokinetic profile of VDZ dose escalation.

Methods

All IBD patients treated with VDZ in one tertiary IBD centre were retrospectively retrieved from the database. According to local protocol, non-responders to standard dosing of 300 mg i.v. of VDZ every 8 weeks, received escalated dose of 300mg i.v. every 6 or 4 weeks. Disease activity was assessed by Harvey-Bradshaw index (HBI) and partial Mayo score in Crohn`s disease (CD) and ulcerative colitis (UC) pts; respectively. VDZ dose was escalated in case of clinically assessed primary non response by week 22 of the treatment or in case of secondary loss of response. Response to dose escalation was defined as a decrease of HBI of ≥2 points, partial Mayo score ≥3 points or endoscopic improvement. VDZ through levels were assessed at the completion of induction and in dose escalated patients after at least two VDZ administrations in shortened interval.

Results

In total, 75 IBD patients were included (mean age 47 years, range 20-90; 36 men; 35 CD/39UC/1 IBD-U). Fifty two pts (69%) were primary responders, out of these 23 pts (44%) required dose escalation at some point of the treatment due to secondary loss of response. Out of 23 primary non-responders, 10 stopped the treatment, the remaining 13 received escalated dose of VDZ.

Altogether, dose escalation was used in 36 pts (48%). There were no differences in the proportion of CD and UC between conventional and escalated dose regimen groups. Among secondary loss of response, the response was recaptured in 15 out of 23 pts (65%} while only two out of thirteen primary non-responders responded to dose escalation.

There were no significant differences in VDZ levels between pts requiring dose escalation and pts with stable response to conventional regimen (mean levels 9,97±1,276 vs. 12,79±1,771 µg/mL; p=n.s.). VDZ levels increased significantly in patients who responded to dose escalation (from 10,12±3,460 to 20,81±3,326 µg/mL; p=0.0497).

Conclusion

Response to vedolizumab can be successfully recaptured in two thirds of secondary non responders by dose escalation. Patients requiring dose escalation do not seem to differ from stable responders with regards to vedolizumab pharmacokinetics.

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