In after hours Tuesday, July 22, 2025, Abivax announced positive results from both of its phase 3 studies using its drug obefazimod (formerly ABX464) for the treatment of adult patients with ulcerative colitis (UC). In essence, both the ABTECT-1 (study 105) and ABTECT-2 (study 106) studies achieved a statistically significant placebo-adjusted clinical remission rate at week 8 (induction period). This was noted to be a large study, and this is not an understatement in the very least. Between both of these ABTECT studies, a total of 1,275 patients were enrolled. Patients either took one of two doses of this drug (25 mg & 50 mg) or a placebo. The truth is that once-daily dosing of obefazimod led to statistical significance in terms of the primary endpoint clinical remission rate at week 8, both as a pooled analysis and individually.
What I mean by this is that when the primary endpoint of clinical remission at week 8 was evaluated for both studies in a pooled fashion (patients given 50 mg of the once-daily drug), there was a 16.4% placebo-adjusted remission rate achieved. This clinical efficacy measure was achieved with a statistically significant p-value of p<0.0001. When looking at each of these late-stage trials, ABTECT-1 and ABTECT-2, in a separate manner, there was a placebo-adjusted clinical remission rate of 19.3% and 13.4%, respectively. Why this trial led to a 500% increase in stock price all has to do with the company obtaining remarkable outcomes. First of all, about 47.3% of the patients had already failed to respond to prior therapy [including that of JAK inhibitors].
Speaking of JAK inhibitors, the company is set to release a more thorough analysis of patients who had an inadequate response to this class of drugs but then did well when given obefazimod. Such detailed data is expected to be released at an upcoming medical conference this year. It is also important to highlight that the other 50% of patients were what is known as advanced treatment naive. Either way, the drug performed well overall in terms of its mechanism of action (MOA) regardless of what subpopulation of UC patients was being treated. A major issue with UC is that patients experience significant inflammation of the colon and rectum.
The science of obefazimd, as a first-in-class oral miR-124 enhancer, is highly ideal in targeting inflammatory disorders like UC. First of all, this drug is not a microRNA drug at all. Instead, it is an oral small molecule that enhances the expression of microRNA miR-124. The purpose of substantially increasing this is because it is said to have an anti-inflammatory effect. The miR-124 expression is enhanced thanks to splicing of a long non-coding RNA. After which, this expression then binds to specific mRNA targets in the cytoplasm. When all is said and done, there are two items that are accomplished, which are stabilization of macrophages to the gut thanks to reduced translation of MCP-1/CCL2 and then stabilization being observed in Th17 cell differentiation and related cytokines thanks to reduced translation of STAT3 and IL-6R.
The competitive advantage that might be noted thus far is the clean safety profile, along with the superb clinical remission rate. It’s not just that statistical significance was achieved for both studies; beyond that, it would offer these UC patients a new type of treatment option. In addition, the clinical data highlighted above exceeded what was specifically achieved in terms of a prior phase 2b study. It is important to keep things in perspective and note that again this was only an 8-week induction period. Another milestone to look forward to relating to this program would be the release of 44-week maintenance results, which are expected to be released in Q2 of 2026. Should the maintenance data turn out in a highly positive manner, then Abivax will be in a position to file a New Drug Application (NDA) to the FDA for obefazimod for the treatment of adults with UC in the 2nd half of 2026.
The key item is that this miR-124 enhancer could actually help patients who don’t respond to advanced therapies like JAK inhibitors. The company has obtained ideal data in UC, but it even has the potential to expand in this indication further for starters. That’s because there is a plan to explore obefazimod in combination studies. Preclinical data has shown that this drug could work exceedingly well in targeting moderate to severe UC when given in combination with FDA-approved Velsipity (etrasimod).
However, the notion of moving forward with combination testing with obefazimod was contingent upon the now-released phase 3 induction data. Lastly, it is also in the process of another expansion opportunity, which would be the advancement of obefazimod in the ongoing phase 2b ENHANCE-CD trial treating patients with Crohn’s Disease (CD). It is expected that 12-week induction data from this particular mid-stage trial will be released in the 2nd half of 2026, marking another milestone to look forward to. The stock price of Abivax closed higher on July 23, 2025, by 500% or more. Separately, the company took advantage of this enormous rise in share price, enacting a $400 million public offering.