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X1 Biotech

RUNX1 inhibitor for inherited small-vessel brain disease

Raised to date

$40K

of $2M offered across 1 Form D filing

Still open
$2M
Investors
2
Last filed
Jun 15, 2026

About

X1 Biotech Inc. is a Needham, Massachusetts preclinical biotechnology company developing small-molecule therapeutics for vascular repair. Its approach modulates a shared upstream regulatory pathway implicated in vascular degeneration and fibrotic disease, with preclinical activity reported across inherited small-vessel disease, pulmonary fibrosis, aberrant angiogenesis in eye disease, and neurodegenerative conditions. The company runs a deliberately narrow pipeline focused on a single lead asset, X101, and was co-founded by Harvard Medical School-affiliated ophthalmology and vascular biology researchers.

Targets a single shared upstream regulator (RUNX1) driving vascular degeneration and fibrosis, using a repurposed small molecule with existing human safety history to reach the clinic faster and more cheaply than a de novo program.

Funding

  • Security to be acquiredFiled Jun 15, 2026Form D
    $40K/ $2M

Product

X101

Preclinical small-molecule therapeutic

A repurposed small-molecule RUNX1 inhibitor (Ro24-7429) being developed first for CADASIL, an inherited cerebral small-vessel disease, with expansion planned into other vascular-degeneration and fibrotic indications.

  • Small-molecule RUNX1 inhibitor targeting a shared upstream driver of vascular and fibrotic disease
  • Repurposed compound (Ro24-7429) with prior human exposure, supporting a capital-efficient path
  • CADASIL-first development strategy with expansion potential into idiopathic pulmonary fibrosis

Built for

Patients with CADASIL and other vascular-degeneration and fibrotic diseases, reached through clinicians and pharmaceutical development partners

People on file