“The major finding from the induction study was that all endpoints were going in the same direction in favor of ABX464, even reaching statistical significance for endoscopy as well, and total and partial Mayo score,” said Dr. Steens.
Patients underwent rectal biopsies at the end of 8 weeks, and miR-124 expression increased more than sevenfold from baseline for those taking ABX464, compared with a small increase in the placebo group (7.69- versus 1.46-fold; P = .004). Expression of miR-124 in total blood also increased – by over 800-fold – at study day 28 for the ABX464 arm. Levels were sustained at more than 700-fold at study day 56 in this group. Placebo arm participants saw an insignificant rise in miR-124 blood levels.
Dr. Steens reported that 22 patients, including 7 who had originally been placebo arm participants, continued into the maintenance phase of the study. Nineteen patients have now had a median of over 400 days of exposure to ABX464, with sustained significant improvement in partial Mayo scores from a baseline of 6 to scores below 2 at 6 and 9 months. Fecal calprotectin scores have dropped from a median 1,044 mcg/g at baseline to 23.5 mcg/g at 9 months.
Next steps include the 12-month assessment, which includes another endoscopy, said Dr. Steens. Also, a phase 2b study is seeking to enroll 232 patients who have moderate to severe ulcerative colitis, with room within the enrollment scheme for new study sites, said Dr. Steens. This larger study will have arms in which the current 50-mg oral dose is doubled and halved, as well as a placebo arm, he said. The medication will also be trialed for Crohn’s disease and rheumatoid arthritis.
The small sample size is an inherent limitation of this early-stage clinical trial, noted Dr. Steens.
Dr. Steens reported being an employee and holding shares in Abivax, which funded the study.
SOURCE: Vermeire S et al. DDW 2019, Abstract 1007.