A Major Step Forward for HHT Treatment: Promising Preclinical Data from Diagonal Therapeutics

We’re excited to share two important updates from our partners at Diagonal Therapeutics. At this week’s European Hematology Association (EHA) Congress, Diagonal Therapeutics presented promising preclinical data demonstrating the potential of their antibody approach to address key challenges in HHT disease manifestations:

• Restoring ALK1-mediated cellular signaling
• Preventing and reversing arteriovenous malformations
• Preventing HHT-associated anemia

And just recently it was also announced that Diagonal’s potential therapy, DIAG723 received an Orphan Drug Designation from the U.S. FDA, alongside a positive ODD opinion from the EMA—an important regulatory milestone that underscores both need and momentum.

Cure HHT has closely partnered with Diagonal from the very beginning of their HHT work—bringing the voice of patients directly into their research.

Why this matters for patients:

This potential therapy, called DIAG723, is expected to begin clinical trials in 2026—and could become the first disease-modifying treatment to enter the clinic for HHT.

The Orphan Drug Designation is a status that gives special support to treatments for rare diseases. This means DIAG723 may benefit from tools that can help move it through the development process more efficiently, getting it to patients faster if proven effective.

We’re proud to stand at the forefront of this progress, alongside our community. Cure HHT is the catalyst driving breakthroughs like this forward—with the ultimate goal of ending the suffering caused by this disease.

We’ll continue to keep you updated on next steps.