Attralus Presents New Data on Its Pan-Amyloid Therapeutic and Diagnostic Candidates at the XIX International Symposium on Amyloidosis (ISA)

• AT-02, the company’s lead pan-amyloid removal therapeutic candidate, is currently being evaluated in a Phase 1 three-part trial and a Phase 2 open label extension trial in ATTR and AL amyloidosis patients to support its use as an immunotherapy in patients with systemic amyloidosis.
• AT-02 binds amyloid in mouse models within one day of injection and remains present in the amyloid 10 days after injection.
• AT-01, the first pan-amyloid diagnostic imaging agent, demonstrated high levels of sensitivity and specificity for detection of cardiac amyloid.
• AT-01 uptake in cardiac amyloid was significantly correlated with measures of cardiac structure, cardiac function, disease staging, cardiac biomarkers, and quality of life measures.
• AT-05 cardiac uptake was observed in ATTR and AL patients with no cardiac uptake in healthy subjects.

BURLINGAME, Calif. – May 30, 2024 – Attralus, Inc., a clinical stage biopharmaceutical company developing transformative medicines to improve the lives of patients with systemic amyloidosis, announced 11 data presentations (from four investigator-initiated trials), including two oral presentations related to the use of ¹²⁴I-evuzamitide (AT-01), the company’s pan-amyloid binding imaging agent in development for the diagnosis of cardiac amyloidosis. The company also announced two presentations from AT-02, including highly encouraging preclinical data for AT-02, the company’s lead pan-amyloid removal therapeutic candidate in an oral presentation. In addition, data were presented from an investigator-initiated trial on 99tc-evuzamitide (AT-05) for the diagnosis of cardiac amyloid, and preclinical data were presented for AT-06, a CAR-macrophage therapy for systemic amyloidosis. In total, 16 abstracts were presented related to Attralus’ pan-amyloid pipeline including three oral and 13 poster presentations at the XIX International Symposium on Amyloidosis (ISA) held in Rochester, MN. on May 26-30, 2024. 

“Diagnosis is a challenging and time-consuming process for systemic amyloidosis patients, with many going years without an accurate diagnosis, and losing critical time in the process,” said Ahmad Masri, M.D., Assistant Professor of Medicine and the Director of Cardiac Amyloidosis and Hypertrophic Cardiomyopathy Centers at Oregon Healthy and Science University. “In our study, we were able to learn important disease characteristics about our patients that we cannot learn from any currently available imaging agent. Quantitative measures of AT-01 cardiac uptake showed correlations with standard measures of cardiac structure and function. The AT-01 data we generated provide an impressive road map to detecting and quantifying amyloid deposits in multiple organs across different types of amyloidosis, with the potential to detect amyloid earlier in the disease process.”

“Current approved therapies for systemic amyloidosis target precursor protein production, reducing the formation of new amyloid, but there is a significant unmet need for new therapies that can remove the existing toxic amyloid fibrils that cause organ damage and mortality,” said Jonathan Wall, Ph.D., Distinguished Professor from the University of Tennessee Graduate School of Medicine. “The preclinical data from AT-02 that we presented demonstrate rapid and persistent binding of AT-02 to amyloid in both AL amyloidoma and AA animal models.  These data provide a highly encouraging foundation for a disease modifying treatment approach for systemic amyloidosis using AT-02, which has the potential to improve outcomes for patients.”

Oral Presentation Details

Abstract Title: Characterization of the Peptide-Antibody Fusion, AT-02- Studies to Support its Use as an Immunotherapy in Patients with Amyloidosis

• Date: May 27, 2024, 10:55-11:05 a.m. CDT
• Presenter: Jonathan Wall, Ph.D., University of Tennessee Graduate School of Medicine

Highlights

• AT-02 binds rapidly and specifically to amyloid in the liver, spleen, and heart in an AA mouse model.
• After a single IV injection, AT-02 can be seen in the liver, spleen, and heart amyloid 7 days after injection.
• AT-02 binds human AL amyloid in a mouse within one day of injection and remains present in the amyloid 10 days after injection.
• AT-02 enhances phagocytosis of ATTRwt amyloid extract at sub-nanomolar concentrations.
• Binding of AT-02 to synthetic AL amyloid fibrils is not inhibited by free light chains.
• AT-02 is stable and retains its bioactivity after nine days in human serum.

 
Abstract Title: Changes in Organ-Specific Amyloid Load Assessed by Serial PET/CT Imaging of Iodine (124I) Evuzamitide – Correlation with Serum Biomarkers

• Date: May 28, 2024, 8:45-8:55 a.m. CDT
• Presenter: Emily Martin, Ph.D., University of Tennessee Graduate School of Medicine

Highlights

• 19 cardiac amyloidosis patients underwent repeat imaging with ¹²⁴I-evuzamitide (AT-01) PET/CT approximately three years after their initial scan.
• All ATTR patients were on a silencer or stabilizer (or both) during the period between AT-01 scans.
• All AL patients were in some form of hematologic remission with most not on therapy.
• The cardiac SUVR mean remained stable in 78% of AL patients, decreased in 11% and increased in 11%. However, the splenic and hepatic SUVR decreased dramatically in a few patients.
• The change in cardiac SUVR from baseline to repeat imaging correlated significantly with the change in serum NT-proBNP in the whole population.

 
Abstract Title: First-in-Human Cardiac and Whole-Body 124I-evuzamitide (AT-01) PET/MRI in Systemic Amyloidosis

• Date: May 28, 2024, 9:05-9:15 a.m. CDT
• Presenter: Morris Kim, M.D., Oregon Health and Science University

Highlights

• In this population of 50 patients (34 cardiac amyloidosis and 16 controls) diagnosed with or suspected to have cardiac amyloidosis, ¹²⁴I-evuzamitide PET/MRI uptake was detected in all patients with cardiac amyloid and in none of the control patients.
• In this single center study in select patients, a simple measure of mean myocardial to LV blood pool SUV ratio ≥1.45 yielded a 100% sensitivity and specificity for the diagnosis of cardiac amyloidosis.
• ¹²⁴I-evuzamitide PET/MRI provided novel information of the distribution of amyloid in the heart, kidney, spleen, liver and lung.
• ¹²⁴I-evuzamitide PET/MRI provided comprehensive diagnostic evaluation and organ survey of patients suspected to have or diagnosed with systemic amyloidosis.

About Systemic Amyloidosis 
Systemic amyloidosis encompasses a diverse group of rare diseases that occur due to accumulation of toxic amyloid deposits in tissues and organs, a consequence of aberrant protein misfolding events. These diseases are progressive, debilitating and often fatal. Systemic amyloidosis is significantly underdiagnosed due to low awareness, lack of specific symptoms, and no current disease-specific diagnostics. There are approximately 17 different types of systemic amyloidosis, which combined represent over 500,000 patients in the United States, the European Union and Japan. The two most common forms of systemic amyloidosis are transthyretin-associated amyloidosis (ATTR) and immunoglobulin light-chain-associated (AL) amyloidosis. While currently approved treatments slow disease progression by targeting precursor proteins, there is a significant unmet need for new therapies that can remove toxic amyloid deposits across all amyloid types and improve organ function and patient quality of life.
 
About AT-02, Pan-Amyloid Removal Therapeutic
AT-02 is the company’s lead pan-amyloid removal (PAR) therapeutic candidate for systemic amyloidosis. AT-02 is a humanized IgG1 monoclonal antibody genetically fused with the company’s proprietary pan-amyloid binding peptide, enabling binding to multiple types of amyloid deposits. The Fc region of the antibody stimulates the immune system to remove amyloid deposits that are bound by AT-02. AT-02 uses a similar pan-amyloid peptide to ¹²⁴I-evuzamitide, the company’s diagnostic agent, which has been shown in multiple clinical trials to selectively bind to amyloid deposits in the heart, liver, kidney, and other organs in multiple types of amyloidosis. As a result, the company expects AT-02 to bind specifically to amyloid in systemic amyloidosis patients. Preclinical data have shown the ability of AT-02 to bind to multiple amyloid types in major organs, induce macrophage mediated phagocytosis, and remove amyloid. AT-02 is currently being evaluated in a Phase 1 three-part trial and a Phase 2 open label extension trial in ATTR and AL amyloidosis patients.
 
About ¹²⁴I-evuzamitide (AT-01) Pan-Amyloid Diagnostic
¹²⁴I-evuzamitide (AT-01) utilizes the company’s pan-amyloid binding peptide as an amyloid-specific imaging agent to image all types of systemic amyloidosis by PET/CT imaging. In clinical trials, ¹²⁴I-evuzamitide has been shown to detect multiple types of amyloid deposits, including AL and ATTR, in major organs such as the heart, kidney, liver, and spleen. Attralus has a special protocol assessment (SPA) in place with the FDA to conduct a single pivotal Phase 3 trial for ¹²⁴I-evuzamitide.
 
About AT-05, Pan-Amyloid Diagnostic
AT-05 uses the same pan amyloid binding peptide as ¹²⁴I-evuzamitide but is labelled with technetium-99m (Tc-99m, ^99mTc). AT-05 is designed to be used with single-photon emission computerized tomography (SPECT) to be more accessible to community cardiologists, and thereby support broader screening in addition to diagnosis. AT-05 is currently in a Phase 1 clinical trial.
 
About AT-06
AT-06 is an additional therapeutic candidate that incorporates differentiated technology to treat all types of systemic amyloidosis. AT-06 incorporates the PAR-peptide into a CAR-M, which is an alternative approach to enabling the immune system to remove amyloid deposits.
 
About Attralus  
Attralus is a clinical stage biopharmaceutical company focused on creating transformative medicines to improve the lives of patients with systemic amyloidosis. The company’s proprietary pan-amyloid removal (PAR) therapeutics are designed to directly bind to and remove toxic amyloid in organs and tissues. By targeting the disease-causing pathology in systemic amyloidosis diseases, PAR therapeutics have the potential to treat and reverse disease in patients with all types and stages of systemic amyloidosis. Attralus was founded by scientific experts in the field of amyloidosis and the company is headquartered in Burlingame, CA.
 
Forward-Looking Statements 
This press release contains forward-looking statements, including statements related to the efficacy, continued development, and potential of AT-01. Words such as “developing,” “potential,” “shown” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Attralus’ current expectations. Forward-looking statements involve risks and uncertainties. Attralus’ actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties. Attralus expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Attralus’ expectations with regard thereto or any change in events, conditions, or circumstances on which any such statements are based.
 
Contact:
Krishna Gorti, M.D. FRCS
Corporate Development
kgorti@attralus.com