OP35 Low remission recapture after ustekinumab dose optimization in Crohn’s disease: results of the randomized placebo-controlled double-blind REScUE study.

Abstract

Background: In Crohn's disease (CD), an exposure-response relationship exists for ustekinumab, with higher serum levels associated with better out-comes. Although several retrospective and observational studies demonstrate dose-escalation of ustekinumab can be effective in case of secondary loss of response (LOR), prospective placebo-controlled data are lacking. The aim of the REScUE study (NCT04245215) was to investigate the effect of 2 different re-induction regimens with ustekinumab on clinical, endoscopic, biological and pharmacological outcomes in patients with CD. Method(s): This Belgian multicentre prospective double-blind randomized placebo-controlled trial included adult patients with CD treated with ustekinumab who presented with secondary LOR to ustekinumab after documented primary response. Secondary LOR was defined by PRO-2 (AP> 1 AND SF> 3) and confirmed by either an elevated biomarker (CRP >5 mg/L or faecal calprotectin >250 mug/mg) or endoscopic signs of inflamma-tion. All patients received a single IV re-induction with ustekinumab (6mg/kg) and were then randomized 1:1 to blinded maintenance ustekinumab 90 mg SC Q4W (intervention) or 90 mg SC Q8W (control) for 48 weeks. Primary endpoint was proportion of patients with steroid-free clinical remission (definition in fig 1) at week 48, with missing data were handled using non-responder imputation. Result(s): In total, 132 patients were screened, and 108 patients were included: 67% female, median [IQR] age 41 [32-54] year, median disease dur-ation 14 [7-22] years. Prior anti-TNF exposure was reported in 92% of patients, while ustekinumab was the first-line advanced treatment in 7% of patients. The primary endpoint of steroid-free clinical remission at week 48 was achieved by 9/54 (17%) patients in the q4w regimen vs 8/54 (16%) in the q8w regimen (p=0.96) (fig 1). Endoscopic remission (SES-CD <3) was achieved in 5/54 (10%) vs 3/54 (6%) (p=0.52), endoscopic re-sponse (>=50% decrease in SES-CD from baseline) was achieved in 11/54 (22%) vs 6/54 (12%) (p=0.23) and 0.52biomarker remission was achieved in 20/54 (38%) vs 13/54 (26%) (p=0.19) in the q4w regimen vs the q8w regimen, respectively. Time to first clinical remission was similar between groups (fig 2). Association with ustekinumab serum levels will be reported. No new safety signals were observed. Conclusion(s): In patients with CD experiencing secondary LOR to ustekinumab, dose optimization with a single IV re-induction followed by intensi-fied maintenance dosing (90 mg SC q4W) was not superior to a single IV re-induction followed by conventional maintenance dosing (90 mg SC q8W) in achieving steroid-free clinical remission. The secondary endpoints were numerically higher but not significant in the intensified regimen.