Vedolizumab was shown to be safe and effective for the treatment of Crohn’s disease (CD) and ulcerative colitis (UC) in the GEMINI long-term safety (LTS) study. The vedolizumab Extended Access Program (XAP) provides patients with continued treatment. The XAP pharmacokinetics (PK) substudy investigated vedolizumab efficacy, safety, and PK.
Vedolizumab dosing frequency was reduced from every 4 weeks (Q4W) to every 8 weeks (Q8W) at XAP enrollment and patients were followed for 56 weeks. Outcomes included efficacy, loss of clinical benefit and re-escalation to Q4W dosing, vedolizumab PK, immunogenicity, and adverse events.
Among 167 enrolled patients (CD=88, UC=79), 80 (91%) with CD and 73 (92%) with UC completed 56 weeks; 76 (86%) and 71 (90%) with CD and UC, respectively, remained on Q8W dosing for 56 weeks. Clinical remission, corticosteroid-free clinical remission, and C-reactive protein levels were stable among patients remaining on Q8W through Week 56. Four patients with CD and 2 with UC resumed Q4W dosing (3 with CD regained clinical response). Patients with CD who completed Week 56 on Q8W dosing had median trough vedolizumab concentrations of 43.6 µg/mL at enrollment and 10.4 µg/mL at Week 56; concentrations were 42.4 µg/mL and 13.3 µg/mL, respectively, in patients with UC. Treatment-related adverse events were infrequent; no new or serious adverse events related to vedolizumab were reported.
In the XAP-PK substudy, adherence to Q8W dosing was high with no loss of efficacy; very few patients required re-escalation to Q4W. There were no new safety signals.

© European Crohn’s and Colitis Organisation (ECCO) 2020.