Diagonal Therapeutics Doses First Patient In Phase 1/2 Trial Of DIAG723 For Rare Vascular Disorder HHT

Diagonal Therapeutics, a clinical-stage biotechnology company developing disease-modifying clustering antibodies for severe diseases, has announced that the first patient has been dosed in the DIAMOND Phase 1/2 clinical trial evaluating DIAG723 for the treatment of hereditary hemorrhagic telangiectasia (HHT). The multicenter study is randomized, double-blind, and placebo-controlled, marking an important milestone in the clinical development of a potential new therapy for this rare genetic vascular disorder.

Hereditary hemorrhagic telangiectasia is a serious inherited disease characterized by fragile and abnormal blood vessels that frequently rupture, causing recurrent bleeding, chronic anemia, and a reduced quality of life. Many patients require regular iron therapy or blood transfusions to manage persistent blood loss. The condition can also lead to arteriovenous malformations (AVMs) in organs such as the lungs, liver, and brain. These abnormal blood vessel connections can rupture and cause severe or even life-threatening complications. Currently, there are no approved therapies that directly treat the underlying cause of HHT.

DIAG723 is a first-in-class clustering agonist antibody designed to restore normal ALK1 signaling, which is disrupted by the genetic mutations responsible for HHT. The therapy works by bringing together receptors on the cell surface to reactivate the signaling pathway, with the goal of correcting the underlying disease process rather than simply treating its symptoms. By restoring normal signaling, DIAG723 is intended to reduce fragile blood vessel formation, recurrent bleeding, anemia, and the development of AVMs.

The initiation of the DIAMOND trial represents an important step in evaluating the safety and potential effectiveness of this novel treatment approach. In preclinical studies, DIAG723 demonstrated the ability to both prevent and reverse the formation of arteriovenous malformations, suggesting that it could potentially modify the course of the disease instead of only managing its complications.

John Lee, M.D., Ph.D., Chief Medical Officer of Diagonal Therapeutics, said HHT is a lifelong genetic disorder that affects many aspects of patients' lives, from frequent nosebleeds and chronic anemia to serious complications caused by AVMs. He noted that existing treatment options primarily focus on controlling bleeding rather than addressing the underlying genetic defect. According to Dr. Lee, DIAG723's ability to restore normal ALK1 signaling offers a differentiated approach that could potentially change the treatment landscape for people living with HHT.

With the first patient now enrolled, Diagonal Therapeutics will continue advancing the DIAMOND clinical trial to evaluate whether DIAG723 can provide a disease-modifying treatment option for patients with hereditary hemorrhagic telangiectasia, a condition that currently has no approved therapies targeting its root cause.