AltruBio Raises $225M for Midphase Ulcerative Colitis Program

AltruBio, a biotechnology firm based in San Francisco, has secured up to $225 million in series B funding to advance its new immune checkpoint enhancer through a mid-phase trial for ulcerative colitis. This development marks a significant shift for the company, which pivoted from oncology to immunology in 2021. AltruBio's new focus is on a drug candidate named ALTB-268, which targets PSGL-1 to regulate T-cell homeostasis.

The company's transition in 2021 involved exiting the oncology sector and shutting down a trial for ulcerative colitis due to the pandemic. At that time, AltruBio was also conducting a study on acute graft-versus-host disease with neihulizumab, an immune checkpoint agonist antibody. However, the company has since moved on from neihulizumab to ALTB-268, a drug with a similar mechanism of action but designed to achieve better efficacy through a tetravalent structure.

In preclinical tests and early human trials, ALTB-268 has shown improved potency in down-regulating chronic pathogenic T cells. This has raised hopes that it can match the efficacy of neihulizumab at lower doses. Furthermore, the safety profile of ALTB-268 is reportedly comparable to that of its predecessor. In 2023, AltruBio completed a phase 1 study of ALTB-268 in healthy volunteers, paving the way for a mid-phase trial in patients with ulcerative colitis who are unresponsive to existing biologics. The company aims to release data on the primary clinical remission endpoint by the first half of 2025 and is planning a phase 2b trial with data expected in the second half of 2026.

BVF Partners has led the $225 million series B funding round, with additional support from new investors such as RA Capital Management, Cormorant Asset Management, and Soleus Capital. Investors from AltruBio's previous $63 million series A funding round, including the lead aMoon Fund, also participated in this latest financing.

While AltruBio's immediate focus is on ulcerative colitis, the mechanism behind ALTB-268 has potential applications in a variety of other diseases. The earlier drug, neihulizumab, demonstrated promise in treating graft-versus-host disease and was studied for psoriatic arthritis and plaque psoriasis. This suggests that ALTB-268 could also be effective in these conditions.

The wide scope of AltruBio's research and development program highlights the crucial role activated T cells play in numerous inflammatory diseases. By binding to PSGL-1, ALTB-268 aims to down-regulate chronically activated T cells without affecting the activity of resting and early-activated T cells. If successful, this approach could target the cells responsible for multiple inflammatory diseases while preserving the function of healthy immune cells.

In summary, AltruBio's strategic pivot and the subsequent development of ALTB-268 position the company at the forefront of innovative treatments for inflammatory diseases. With substantial financial backing and promising early results, AltruBio is well-equipped to advance its clinical programs and potentially deliver new therapies for conditions that currently have limited treatment options.