Telitacicept Demonstrates Deep and Durable Minimal Symptom  Expression Through 48 Weeks in Generalized Myasthenia Gravis

More than 94% of participants achieved a ≥5-point MG-ADL improvement at Week 48

42% of telitacicept-treated participants achieved minimal symptom expression (MSE) at any time over 48 weeks, increasing from 23.7% over the first 24 weeks

After achieving MSE, 86.7% of MSE events were sustained at the next monthly assessment and participants spent 83-85% of remaining study follow-up in MSE

Approximately 51% of participants with baseline MG-ADL scores of 6-10 and 21% of participants with baseline MG-ADL scores ≥11 achieved MSE

BOSTON, Sept. 29, 2026 (GLOBE NEWSWIRE) -- Vor Bio (Nasdaq: VOR), a clinical-stage biotechnology company transforming the treatment of autoimmune diseases, today announced a new post hoc analysis from the Phase 3 trial conducted in China by its collaborator, RemeGen Co., Ltd (HKEX: 9995, SHA: 688331), evaluating telitacicept in adults with generalized myasthenia gravis (gMG). The findings were presented in an oral presentation during the Myasthenia Gravis Foundation of America (MGFA) Scientific Session at the 2026 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Annual Meeting in Orlando, Florida.

The analysis evaluated the depth and durability of clinical response to telitacicept over 48 weeks, including achievement of MSE, defined as a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 0 or 1. In addition to evaluating whether participants achieved MSE, the analysis assessed whether MSE was sustained at the subsequent monthly assessment and the proportion of remaining follow-up participants spent in MSE after achieving it. The Phase 3 study randomized 114 adults with gMG to telitacicept 240 mg once weekly or placebo for 24 weeks, followed by a 24-week open-label extension (OLE), with those previously on placebo crossing over to telitacicept 240mg. The initial 48-week OLE data were presented at the MGFA Scientific Session at the 2025 AANEM Annual Meeting.

“Over the past decade, myasthenia gravis has seen meaningful therapeutic innovation, but patients and physicians still live with uncertainty about whether a treatment will work broadly and whether that benefit will last,” said Jean-Paul Kress, M.D., Chairman and Chief Executive Officer of Vor Bio. “What stands out in these data are the breadth, depth, and durability of response, with more than 94% of participants achieving at least a five-point improvement in MG-ADL, more than half of those starting with MG-ADL scores of 6-10 reaching MSE, and once MSE was achieved, participants spent the vast majority of their remaining follow-up in that state. If UPSTREAM MG can reproduce this profile globally, we believe telitacicept could give physicians greater confidence in treatment choice and patients greater predictability in how they live their lives.”

“Clinically, reaching MSE once or over a short period is not the same as sustaining that level of disease control over time,” said Richard J. Nowak, M.D., M.S., Director of the Yale Myasthenia Gravis Clinic and Associate Professor of Neurology at Yale School of Medicine. “Myasthenia gravis symptoms can fluctuate over time, so a single assessment provides only a limited window into patient outcomes. These data are encouraging because the response to telitacicept appears to deepen with continued treatment and extends across a broad range of baseline disease severity. As treatment options improve, longitudinal assessment and transparent reporting of MSE durability should become an increasingly important standard so patients and clinicians can better understand not only whether minimal symptoms can be achieved but how consistently they can be maintained.”

Key Findings from the Post Hoc 48-week Analysis:

• Durability of MSE: Among participants who reached MSE, 86.7% of MSE events were sustained at the next monthly assessment. Following achievement of MSE, participants spent the vast majority of their remaining study follow-up in MSE, specifically 83% among those initially randomized to telitacicept and 85% among those who crossed over from placebo to telitacicept.
  

• MSE across disease severity: More than half of participants with baseline MG-ADL scores of 6-8 (51.2%) and 9-10 (51.7%) achieved MSE during the 48-week study. Importantly, 20.5% of participants with baseline MG-ADL scores ≥11 also achieved MSE.
  

• Depth of response increased with continued treatment: MG-ADL responses continued to deepen from Week 24 through Week 48, with increasingly stringent response thresholds achieved over time and MG-ADL improvements of up to 13 points observed at Week 48.
  

• Overall MSE attainment: The probability of achieving MSE at any time over the 48-week study was approximately 42% among participants treated with telitacicept.
  

• Safety: Telitacicept was generally well tolerated through 48 weeks with no new safety signals observed, consistent with the previously reported safety profile from the study.
  

About Generalized Myasthenia Gravis
gMG is a rare, chronic autoimmune neuromuscular disorder that disrupts communication between nerves and muscles, leading to muscle weakness that can impact mobility, vision, swallowing, and breathing. The disease is mediated by autoantibodies, most commonly targeting the acetylcholine receptor (AChR) or muscle-specific kinase (MuSK), which interfere with neuromuscular transmission. While several therapies are available, many patients continue to experience persistent symptoms or intolerable side effects. As a result, there remains a significant unmet need for new therapies that offer durable efficacy, a favorable safety profile, and convenient administration to improve the quality of life for people living with gMG.

About Telitacicept
Telitacicept is a novel recombinant fusion protein designed to treat autoimmune diseases through dual inhibition of BLyS (BAFF) and APRIL - two cytokines essential to B cell and plasma cell survival. This dual-target mechanism reduces autoreactive B cells and autoantibody production, key drivers of autoimmune pathology.

Telitacicept is approved in China for systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), generalized myasthenia gravis (gMG), IgA nephropathy (IgAN), and Sjögren’s disease (SjD).

Vor Bio is advancing telitacicept in global Phase 3 trials in gMG and SjD to support potential regulatory approvals in the United States, Europe, and Japan.

About Vor Bio
Vor Bio is a clinical-stage biotechnology company transforming the treatment of autoimmune diseases. The Company is focused on rapidly advancing telitacicept, a novel dual-target fusion protein, through Phase 3 clinical development and potential commercialization to address serious autoantibody-driven conditions worldwide. For more information visit www.vorbio.com. Vor Bio routinely posts information that may be important to investors in the “Investors” section of its website. The Company encourages investors to consult that section of its website regularly.

Forward-Looking Statements
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