Why is Abivax Stock Price (NASDAQ:ABVX) Up So Much?

Abivax SA (NASDAQ: ABVX) witnessed an extraordinary surge in its stock price following the announcement of positive Phase 3 trial results for its ulcerative colitis drug, obefazimod. The drug met its primary endpoint in two major Phase 3 studies.

Today's session has seen ABVX's stock price add a remarkable 554%. This dramatic increase followed the release of data indicating that obefazimod demonstrated significant efficacy. Nearly half of the patients in the trials had previously failed other advanced therapies.

The safety profile of obefazimod remained consistent with earlier trials. Abivax now plans to submit for U.S. and European regulatory approvals in 2026, contingent on favorable long-term results.

Prior to the Phase 3 results announcement, ABVX closed at $10, before opening today at $63.10.

The positive Phase 3 ABTECT trial results revealed that the 50 mg once-daily dose of obefazimod achieved a pooled placebo-adjusted clinical remission rate of 16.4% (p<0.0001) at Week 8 across the ABTECT-1 and ABTECT-2 trials. Individually, the 50 mg dose demonstrated a placebo-adjusted remission rate of 19.3% (p<0.0001) in ABTECT-1 and 13.4% (p=0.0001) in ABTECT-2.

According to Abivax, 47.3% of participants had previously inadequate responses to advanced therapies, including a significant population of patients with inadequate response to JAK inhibitor therapy. Obefazimod also maintained a favorable safety profile, with no new safety signals.

Abivax completed enrollment for the Phase 3 ABTECT trials on April 29, 2025, exceeding the target by 4% with 1,275 participants. The company anticipates 44-week maintenance data in Q2 2026.