Aligos Therapeutics Presents Update on Development of SARS-CoV-2 Therapeutic Candidate and Screening Method in Collaboration with KU Leuven at RespiDART & Emerging Viruses 2020

SOUTH SAN FRANCISCO, Calif., Dec. 17, 2020 (GLOBE NEWSWIRE) -- Aligos Therapeutics, Inc. ALGS, a clinical stage biopharmaceutical company focused on developing novel therapeutics to address unmet medical needs in viral and liver diseases, today announced that the company delivered an oral and poster presentation today at the RespiDART & Emerging Viruses 2020 meeting. The presentation highlighted the company's progress with developing a SARS-CoV-2 therapeutic candidate, as well as the development of a screening method to assess potential candidates. Aligos performed all research in collaboration with Belgian University KU Leuven, in particular its Centre for Drug Design and Discovery (CD3), and the Rega Institute for Medical Research.

The presentation, titled "Structure-based discovery of potent and selective SARS-CoV-2 3-chymotrypsin-like cysteine protease inhibitors using a multiplex screening platform," describes the authors' mass spectrometry-based assay developed to assess putative coronaviral 3-chymotrypsin-like cysteine protease (3CL_pro) inhibitors in development for therapeutic use against SARS-CoV-2, including Aligos' own 3CL_pro inhibitor candidate, ALG-097111. Coronaviral 3CL_pro is a promising therapeutic target, as it is essential and conserved among coronaviruses but is not found in humans.

Aligos and collaborators launched a structure-based approach to identify novel coronaviral 3CL_pro inhibitors that were evaluated in the in-house developed multiplex SARS-CoV-2 3CL_pro/human rhinovirus 3C (HRV3C) protease assay to assess their specificity and selectivity.

Unlike all other SARS-CoV-2 3CL_pro compounds tested with the screening platform to date, Aligos' lead compound ALG-097111 demonstrated potent SARS-CoV-2 3CL_pro inhibition, without inhibiting human cathepsin L protease activity up to the highest concentration tested (IC₅₀ > 10 µM). Cathepsin L has been shown to be involved in a highly redundant entry pathway of SARS-CoV-2 into different cell types. As the competition between the viral 3CL_pro and the host cathepsin L might eventually act as a decoy mechanism in vivo, the identification of potent inhibitors selective for the viral 3CL_pro represents an important breakthrough.

"We are pleased that our work with CD3 and the Rega Institute has yielded a platform that we can use to optimize our SARS-CoV-2 3CL_pro inhibitors," said Pierre J.M.B. Raboisson, Pharm.D. Ph.D., Vice President, Head of Small Molecule Medicinal Chemistry and European Site Head at Aligos. "A highly specific, selective small molecule anti-coronaviral therapeutic will likely be indispensable as part of an effective treatment regimen against SARS-CoV-2, whereas treatments repurposed from other viral indications may fall short. We are encouraged to see potent protease inhibition activity with ALG-097111 and we continue to refine the candidate's chemistry for optimal potency."

About Aligos

Aligos Therapeutics, Inc. is a clinical stage biopharmaceutical company that was founded in 2018 with the mission to become a world leader in the treatment of viral infections and liver diseases. Aligos is focused on the discovery and development of targeted antiviral therapies for chronic hepatitis B (CHB) and coronaviruses as well as leveraging its expertise in liver diseases to create targeted therapeutics for nonalcoholic steatohepatitis (NASH). Aligos' strategy is to harness the deep expertise and decades of drug development experience its workforce has in liver disease, particularly viral hepatitis, to rapidly advance its pipeline of potentially best-in-class molecules.

Forward-Looking Statement

This press release contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Any statements in this press release that are not historical facts may be considered "forward-looking statements," including without limitation statements regarding the ability to use the platform arising from the collaboration with CD3 and the Rega Institute to optimize SARS-CoV-2 3CL_pro inhibitors; the likelihood of specific, selective small molecule anti-coronaviral therapeutic being indispensable as part of an effective treatment regimen against SARS-CoV-2; and the continued refinement of the chemistry of ALG-097111 for optimal potency. Forward-looking statements are typically, but not always, identified by the use of words such as "may," "will," "would," "believe," "intend," "plan," "anticipate," "estimate," "expect," and other similar terminology indicating future results. Such forward-looking statements are subject to substantial risks and uncertainties that could cause our development programs, future results, performance or achievements to differ materially from those anticipated in the forward-looking statements. Such risks and uncertainties include without limitation risks and uncertainties inherent in the drug development process, including Aligos's clinical-stage of development, the process of designing and conducting clinical trials, the regulatory approval processes, the timing of regulatory filings, the challenges associated with manufacturing drug products, Aligos's ability to successfully establish, protect and defend its intellectual property, other matters that could affect the sufficiency of Aligos's capital resources to fund operations, reliance on third parties for manufacturing and development efforts, changes in the competitive landscape and the effects on our business of the worldwide COVID-19 pandemic. For a further description of the risks and uncertainties that could cause actual results to differ from those anticipated in these forward-looking statements, as well as risks relating to the business of Aligos in general, see Aligos's prospectus filed with the Securities and Exchange Commission on October 19, 2020, and its future periodic reports to be filed with the Securities and Exchange Commission. Except as required by law, Aligos undertakes no obligation to update any forward-looking statements to reflect new information, events or circumstances, or to reflect the occurrence of unanticipated events.

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