Mozart Therapeutics Completes Ph1a Study in Healthy Adults; Data Shows MTX-101 is Well Tolerated and Selectively Activates CD8 Treg

Enrollment of Patients with Autoimmune Disease in Phase 1b Study has Begun

SEATTLE, March 17, 2025 /PRNewswire/ -- Mozart Therapeutics, the leading developer of CD8 Treg modulators for the treatment of autoimmune disease, today announce the successful completion of their Phase 1a study of MTX-101 in healthy adults. The randomized, blinded, placebo-controlled study evaluated MTX-101—a first-in-class autoimmune checkpoint inhibitor—as single and multiple doses in an ascending-dose design (NCT06324604).

Data from the study in healthy adults show MTX-101 is well tolerated. Most adverse events were low-grade and there were no serious adverse events. Participants receiving MTX-101 experienced transient and self-limited decreases in lymphocytes, which the Company believes are consistent with the study drug's mechanism of action and indicative of target engagement.

Data further demonstrate that MTX-101 has predictable, dose-dependent pharmacokinetics (PK) and receptor occupancy that are expected to enable a convenient and competitive dosing regimen. Pharmacodynamic data support proof of mechanism and show that MTX-101 is highly selective for regulatory CD8 T cells, and that engagement with MTX-101 results in CD8 Treg activation.

Mozart plans to present full data from the Phase 1a study at upcoming medical symposia.

"We are thrilled that the initial MTX-101 Phase 1 data in healthy adults confirm the mechanistic and safety findings from our pre- and nonclinical studies. This represents not only an important milestone for Mozart, but also a significant achievement as we work to advance a class of CD8 Treg modulators to restore durable immune homeostasis in autoimmune disease," said Katie Fanning, President and Chief Executive Officer of Mozart Therapeutics.

"Our observations from the healthy adults hold great promise for patients with autoimmune disease," echoed Jason Chien, M.D., M.S., Mozart's Chief Medical Officer. "The well-tolerated safety profile, antibody-like PK, and clear evidence of target engagement and activation represent an exciting novel class of therapeutics that has the potential to deliver substantial clinical benefit. With these data, we are quickly advancing MTX-101 in patients with type 1 diabetes and celiac disease."

The first patients with type 1 diabetes and celiac disease have been enrolled in Part B of the study, which is being conducted at multiple clinical sites in Australia. "MTX–101 has a novel mechanism of action that has great potential to improve the lives of people living with autoimmune disease," said Professor John Wentworth, M.D.; Endocrinologist, The Royal Melbourne Hospital Department of Medicine; Senior Clinical Research Fellow, St Vincent's Institute of Medical Research; Director, ANZ Type 1 Diabetes TrialNet. "This is why our type 1 diabetes community is so excited to participate in the MTX-101 development program and help determine its ability to decrease dependance on insulin injections."

About MTX-101

MTX-101 is an antigen-agnostic bispecific antibody targeting inhibitory KIR and CD8 expressed on regulatory CD8 T cells. This autoimmune checkpoint inhibitor aims to restore the intrinsic functions of CD8 Treg, acting early in the autoimmune disease process to suppress and eliminate pathogenic T cells, halt downstream inflammation, and prevent tissue destruction.

About Mozart Therapeutics

Mozart Therapeutics is focused on developing first-in-class disease-modifying therapies for autoimmune diseases, utilizing a novel approach to restoring immune system function by targeting the CD8 T regulatory network. The company is headquartered in Seattle, WA. For more information, visit www.mozart-tx.com and follow the company on LinkedIn @Mozart–tx.com. 

SOURCE Mozart Therapeutics