Hillstar Bio is a technology company.
Hillstar Bio™ is shaping a new era in autoimmune disease treatment through precision immunology. We selectively target and deplete pathogenic immune cells while sparing healthy ones.
Hillstar Bio has raised $67.0M across 1 funding round.
Hillstar Bio has raised $67.0M in total across 1 funding round.
Hillstar Bio is a Boston-based biotechnology company developing precision immunology therapies for autoimmune diseases. It selectively targets and depletes pathogenic immune cells, such as TRBV9+ T cells, while sparing healthy ones, aiming to reset the immune system and provide durable relief without the broad immunosuppression risks of traditional treatments.[1][2][3] The company's lead program, HSB-101, focuses on axial spondyloarthritis (AxSpA), with preclinical work advancing toward clinical trials in 2026, supported by a $67 million Series A raised in March 2025 from investors including Droia Ventures, Frazier Life Sciences, Novo Holdings, and LifeArc Ventures.[1][3][4] This funding fuels pipeline expansion into other HLA-B27-associated immune conditions, serving patients underserved by chronic therapies that fail to address disease roots.[2][5]
Founded in 2023 in Boston, Hillstar Bio emerged from expertise in antibody engineering and immunology, led by CEO Robert Mabry (ex-Takeda biologics head and Orna Therapeutics CSO), Chief Development Officer Mitchell Keegan (ex-Boston Pharmaceuticals SVP), and COO Lauren Mifflin (ex-Frazier Life Sciences).[3][4] The idea crystallized around targeting specific pathogenic T cell subsets like TRBV9+, inspired by early clinical data showing remission in ankylosing spondylitis patients after depletion, addressing gaps in AxSpA treatments that require lifelong dosing and increase infection risks.[1][4] Pivotal early traction came with the $67 million Series A launch in March 2025, enabling rapid progression of HSB-101 and formation of a Clinical Advisory Board in September 2025 with spondyloarthritis experts.[3][5]
Hillstar Bio rides the precision medicine wave in immunology, shifting autoimmune treatment from symptomatic suppression to root-cause elimination amid rising demand for targeted biologics.[1][2] Timing aligns with post-JAK inhibitor era learnings, where failures highlight needs for durable, less-toxic options in $100B+ markets like rheumatology.[4] Favorable forces include advancing biomarkers (e.g., HLA-B27/TRBV9 links) and investor appetite for de-risked biotechs, as seen in its oversubscribed Series A.[3] By influencing ecosystems through advisory boards and pipeline sharing, Hillstar accelerates adoption of cell-depleting therapies, potentially reshaping standards for AxSpA and beyond.[5]
Hillstar Bio is primed for 2026 milestones with HSB-101 entering clinic, validating its TRBV9 approach in AxSpA proof-of-concept trials amid biomarker-driven trial efficiencies.[1][5] Expanding pipelines will leverage AI-enhanced discovery and combo therapies, shaped by trends like immune mapping and reduced-dosing regimens to cut chronic therapy burdens.[2][4] Its influence could grow via partnerships or buyouts if data confirms remissions, evolving from stealth biotech to category leader in precision autoimmune resets—transforming "management" into potential cures, as its Series A launch boldly signaled.[1][3]
Hillstar Bio has raised $67.0M in total across 1 funding round.
Hillstar Bio's investors include Frazier Healthcare Partners, Norwest Venture Partners, Omega Funds.
Hillstar Bio has raised $67.0M across 1 funding round. Most recently, it raised $67.0M Series A in March 2025.
| Date | Round | Lead Investors | Other Investors |
|---|---|---|---|
| Mar 1, 2025 | $67.0M Series A | Frazier Healthcare Partners, Norwest Venture Partners, Omega Funds |