AltruBio Raises $225M in Series B for Immune Checkpoint Program Development

AltruBio Inc., a clinical-stage biotechnology firm based in San Francisco, has announced the completion of a Series B financing round, raising up to $225 million. This financing round was oversubscribed and is intended to propel the clinical development of the company's innovative immune checkpoint enhancer (ICE) PSGL-1 agonist antibody, ALTB-268, particularly in treating ulcerative colitis (UC).

The financing was spearheaded by BVF Partners LP and included contributions from new investors such as RA Capital Management, Cormorant Asset Management, and Soleus Capital. Existing investors aMoon Fund and Blackstone Multi-Asset Investing also participated, alongside other new and current investors. The influx of funds will support ongoing and forthcoming Phase 2a and 2b clinical trials for ALTB-268 in UC, a disease characterized by inflammation and ulcers in the digestive tract.

ALTB-268 is currently under investigation in a Phase 2a exploratory biomarker study aimed at patients with biologic-refractory UC. This study's primary endpoint is clinical remission, measured by the modified Mayo score, with results expected in the first half of 2025. Additionally, AltruBio plans to launch a global Phase 2b randomized, placebo-controlled clinical trial. This trial will focus on both advanced therapy-experienced and treatment-naive patients with moderate to severe UC, targeting a primary endpoint of clinical remission. The outcome of this study is anticipated in the second half of 2026.

Dr. Judy Chou, President and CEO of AltruBio, expressed gratitude for the new and existing investors' support. She highlighted that the collective backing confirms the potential of AltruBio's programs and the company's mission to develop sustainable biologic therapies for autoimmune diseases. Dr. Chou emphasized that the significant investment brings the company closer to advancing ALTB-268 through the ongoing Phase 2a study and initiating the Phase 2b trial. She believes this progress could pave the way for expanding ALTB-268's indications beyond UC, enhancing treatment options for various autoimmune diseases.

Gorjan Hrustanovic, Ph.D., Managing Director at BVF Partners LP, voiced excitement about supporting AltruBio. He noted the limited treatment options for many autoimmune conditions, including moderate to severe UC, and the need for new mechanisms of action. Hrustanovic believes AltruBio's potential first-in-class medicine could significantly impact multiple autoimmune indications, starting with UC.

Jake Simson, Ph.D., Partner at RA Capital Management, echoed similar sentiments. He highlighted the dynamic and evolving landscape of inflammatory and immunological diseases and the urgent need for innovative solutions. Simson stated that the substantial funding in this sector reflects a shared vision with AltruBio to advance first-in-class medicines, potentially revolutionizing patient care and driving significant change within the field.

ALTB-268 is a tetravalent PSGL-1 agonist antibody designed as an immune checkpoint enhancer. It aims to downregulate chronically activated T-cells by inhibiting their effector functions, promoting T-cell downregulation, and restoring the immune system's balance without systemic suppression. The unique mechanism of ALTB-268, similar to the bivalent intravenously administered ICE ALTB-168, has demonstrated promising Phase 2 results in UC, psoriasis, psoriatic arthritis, and steroid-refractory acute graft-versus-host disease (SR/TR-aGvHD). ALTB-268 also showed increased potency in preclinical studies and is formulated for subcutaneous dosing, making it more patient-friendly.

AltruBio's mission, led by a team with successful track records in drug development and commercialization, is to develop safer, more effective, and durable biologic treatments to improve patients' lives. The recent financing, alongside ongoing research and clinical trials, positions AltruBio to accelerate its efforts in delivering innovative treatments to those in need.