Less than a month after its stock roller-coastered on safety signals associated with its late-stage ulcerative colitis (UC) drug candidate obefazimod, shares of Abivax (Euronext Paris and Nasdaq: ABVX) enjoyed smoother sailing this past week—namely a 63% surge in Europe and a 50% leap in the United States over four trading days, following more positive data that appeared to reassure investors.
Abivax declared that obefazimod “delivered meaningful clinical benefit” to adults with moderately to severely active UC in the ABTECT Maintenance Part 2 supplemental portion of its Phase III UC maintenance program, with 37.2% of induction nonresponders achieving clinical remission and 34.5% achieving endoscopic remission at Week 44 following continued 50 mg treatment. Of those patients, 61.5% also showed clinical response, 48.0% endoscopic improvement, and 44.6% Histologic-Endoscopic Mucosal Improvement (HEMI).
In patients whose doses were escalated to 50 mg, clinical remission was recaptured in 45.5% of patients who relapsed during ABTECT Maintenance Part 1—a result Abivax said supported a practical dose-escalation strategy for regaining and sustaining disease control over time.
Of special interest to investors, no new safety signals were seen since earlier this month, when Abivax disclosed various malignancies in nine patients among the 580 enrolled in the study. The earlier disclosure triggered price plunges of 44% for both Abivax’s ordinary shares traded on Euronext Paris and the company’s American depositary shares (ADSs) traded on the Nasdaq Global Market.
The latest data from ABTECT Maintenance Part 2 showed four total cases of non-melanoma skin cancer (NMSC)—two in the study’s 25 mg arm, two in the 50 mg arm: “All occurred in patients with established NMSC risk factors including advanced age, thiopurine use, prior skin cancer history, and failure of multiple prior advanced therapies,” Abivax stated. Significantly, incidence rates of malignancies (including NMSCs) when adjusted for patient-year exposure were well within the pre-defined background reference ranges based on previous UC studies.
Exposure-adjusted incidence rates (EAIRs) for malignancies excluding NMSC were 0.48 and 0.69 events per 100 person-years (PYs) in the all-active combined (50 mg + 25 mg) and 50 mg cohorts, respectively, and for NMSC were 0.95 and 0.69 events per 100 PYs, in the all-active combined (50 mg + 25 mg) and 50 mg cohorts respectively, all consistent with expected UC background rates.
“The expanded cumulative safety data further strengthens our confidence in the long-term safety profile of obefazimod and reinforces the favorable benefit-risk profile for our program as we prepare for our planned NDA [New Drug Application] submission later this year,” Abivax CEO Marc de Garidel stated. “We believe this growing body of evidence positions obefazimod, if approved, to become a paradigm-defining treatment option for patients living with ulcerative colitis.”
Investors appeared to share de Garidel’s optimism. The data sparked a buying surge among investors, who sent Abivax shares traded on Euronext Paris soaring 39% the day after the announcement, from €83.30 ($94.71) to €115.50 ($131.31) on Tuesday. The shares rose another 1.7% Wednesday, closing at €117.50 ($133.59), then climbed another 9% Thursday to €127.80 ($145.28) before finishing the week with a 6% increase, to €135.80 ($154.38) and a 63% one-week gain.
On Nasdaq, Abivax ADSs surged 50% for the week, consisting of a roughly 39% leap Tuesday from $96.15 to $133.26. From there, shares dipped 0.5% the following day to $132.56, before rebounding 9% Thursday, finishing the Independence Day holiday-shortened week at $144.65.
Abivax also requested a temporary, single-day halt to price an upsized offering of its U.S. American depositary shares (ADSs), which increased from the originally announced $600 million to $800 million—6.4 million ADSs at $125 per ADS, expected to extend its cash runway into the second quarter of 2029. The offering closed Thursday at $920 million, with approximately $874.1 million in net proceeds, after underwriters exercised their option to purchase 960,000 additional ADSs.
The size of the offering appeared to address speculation about Abivax being a prime candidate for a buyout, as the company is featured in GEN’s recent A-List of Top 10 Takeover Targets of 2026. However, the upsizing of the offering rekindled buyout speculation among retail investors. Abivax intends to use the net proceeds toward commercialization expenses for obefazimod in the U.S., clinical R&D expenses for UC and Crohn’s disease, and general corporate purposes.
“Response rates (clinical & endoscopic remission) in this portion also appear compelling, especially given the refractory nature of patients in this subset, reaffirming obe’s best-in-disease efficacy,” Thomas J. Smith, senior managing director at Leerink Partners, commented in a research note. Smith raised his firm’s 12-month price target on Abivax shares by 6%, from $140 to $148, with two other firms also raising their price targets on Abivax stock.
Even more positive feedback came from Faisal Khurshid of Jefferies, who upgraded his firm’s rating on Abivax’s stock from “Hold” to “Buy,” boosting Jefferies’ price target by 46%, from $108 to $158. Khurshid noted that while there are still risks regarding cash runway and commercial needs for a potential standalone launch, good data should generate value.
Obefazimod, a small molecule upregulator of miR-124, enhances the selective splicing of a long noncoding RNA to downregulate inflammatory cytokines and chemokines. Initially developed against HIV, it was repurposed to address inflammatory conditions due to its anti-inflammatory effects.
Get started today with Solo access →
