Rheos Medicines to Present Data at ASH 2021 for MALT1 Inhibition for Treatment of Graft-Versus-Host Disease

Rheos Medicines, a biopharmaceutical company bringing molecular targeting and precision treatment to autoimmune and inflammatory diseases, today announced it will present preclinical data showing the potential for MALT1 inhibitors for the treatment of chronic Graft-Versus-Host Disease (GVHD) at the 63^rd Annual Meeting of the American Society of Hematology (ASH) which will be held virtually and in person in Atlanta from December 11-14, 2021. The results demonstrating MALT1 inhibition support Rheos's lead product candidate, RHX-317, a novel, small molecule MALT1 inhibitor, that the company is initially developing for the treatment of chronic GVHD with potential for other autoimmune and inflammatory diseases.

The details of Rheos's presentation at ASH 2021 are as follows:

• Title: Allosteric Inhibition of MALT1 is Efficacious in a Model of Chronic Graft-Versus-Host Disease (cGVHD) and Modulates Immunometabolic Activation
• Poster session: Abstract Number 3810, Session 701, Experimental Transplantation: Basic and Translational: Poster III
• Date and time: Monday, December 13^th, 6:00 - 8:00 p.m. ET
• Location: Hall BH at Georgia World Congress Center and via virtual meeting registration
• Authors: Joanna R. DiSpirito, PhD, Mehmet G. Badur, PhD, Brad Biswas, PhD, Diogo M. Camacho, PhD, Aditi Chalishazar, Brian DeChristopher, PhD, Katie Sellers, PhD, Mya Steadman, Keng Soh, PhD, John Monroe, PhD, Andrew Long, PhD

About MALT1

MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) is a dual-function scaffolding molecule and paracaspase that is expressed preferentially in immune cells. In addition to its role in NF-?B mediated lymphocyte activation and proliferation, Rheos has shown that MALT1 activity is central to the anabolic shift that fuels pathogenic functions of immune cells. Inhibiting MALT1 attenuates the activity of multiple immune cell types simultaneously to dampen the inflammatory response in the activated immune system. Because of its role in cellular metabolism, the effects of MALT1 inhibition can be monitored by metabolite signatures, opening an opportunity to monitor disease and evaluate activity of therapeutics in patients and patient subsets.

About Rheos Medicines

Rheos Medicines is a biopharmaceutical company developing novel, small molecule medicines to treat autoimmune and inflammatory diseases with greater precision by targeting the metabolic hubs of the immune system. Using our proprietary MetPMtm platform, the Rheos team integrates an unmatched knowledge base of immunometabolism networks based on bioinformatic integration of genetic, transcriptomic, epigenomic and metabolomic datasets, including from patient data and samples. We have built a pipeline of novel, differentiated drug programs to address autoimmune and inflammatory diseases by targeting fundamental underpinnings of immune system dysfunction while, at the same time, identifying the molecular signatures for patient stratification and selection. Rheos has assembled leading scientists whose discoveries opened the field of immunometabolism, clinicians with a deep understanding of immune-mediated diseases, and an experienced biotech leadership team. Rheos was founded by Third Rock Ventures and is located in Cambridge, MA. For more information, please visit www.rheosrx.com/. We invite you to follow us on LinkedIn and @Rheosrx.