Eidos Therapeutics Announces Publication of AG10 Molecular Design in Journal of Medicinal Chemistry

SAN FRANCISCO, Aug. 23, 2018 (GLOBE NEWSWIRE) — Eidos Therapeutics, Inc. (Eidos) (Nasdaq:EIDX) today announced publication of the design and preclinical characterization of its lead product candidate, AG10, in the Journal of Medicinal Chemistry.

AG10 is designed to prevent progression of transthyretin (TTR) amyloidosis (ATTR) by stabilizing tetrameric TTR in the blood. AG10 is currently being evaluated in a Phase 2 study in patients with symptomatic ATTR cardiomyopathy (NCT03458130).

“Stabilizing transthyretin has been validated as an approach for treating ATTR based on the correlation of genetic mutations with disease progression and the success of previous clinical trials in the disease. A comparison of various TTR stabilizers and their potency based on structural evidence has not been previously conducted,” said Mamoun Alhamadsheh, PhD, co-founder of Eidos and associate professor at the University of the Pacific (Stockton, CA). “We believe our results provide strong evidence that AG10’s potentially superior stabilizing activity is driven by its unique ability to mimic the disease-protective T119M mutation and its selectivity for binding TTR in the plasma.”

The published paper demonstrates that AG10’s binding to TTR is driven by molecular interactions that mimic the structure of the T119M TTR variant that is known to protect carriers from developing ATTR and leads to prolonged lifespan in otherwise healthy individuals. Using in vitro and ex vivo assays, the data indicated that:

• AG10 demonstrated more potent activity than other clinical candidates in binding and stabilizing the TTR tetramer at clinically relevant concentrations,
• the binding of AG10 to TTR was not significantly affected by the presence of additional plasma proteins such as albumin, and
• AG10 exhibited a predictable relationship between pharmacokinetics and pharmacodynamics in animal studies.

“This newly published paper describes the preclinical support for AG10 and further validates AG10’s mechanism to potently and selectively stabilize TTR,” said Uma Sinha, PhD, chief scientific officer of Eidos. “As a result, AG10 has the potential to be a disease-modifying therapy for ATTR, which we are evaluating in our ongoing Phase 2 study in symptomatic ATTR cardiomyopathy patients.”

About AG10

AG10 is an orally-administered small molecule designed to potently stabilize tetrameric transthyretin, or TTR, thereby halting at its outset the series of molecular events that give rise to amyloidosis, or ATTR. AG10 is currently being examined in a Phase 2 clinical trial in patients with ATTR cardiomyopathy. Top-line results from this trial are expected to be reported by the end of 2018.

AG10 was designed to mimic a naturally-occurring variant of the TTR gene (T119M) that is considered a “rescue mutation” because it has been shown to prevent ATTR in individuals carrying pathogenic, or disease-causing, mutations in the TTR gene. To our knowledge, AG10 is the only TTR stabilizer in development that has been observed to mimic the “super-stabilizing” properties of this rescue mutation.

About Eidos Therapeutics

Eidos Therapeutics is a clinical stage biopharmaceutical company focused on addressing the large and growing unmet need in diseases caused by transthyretin (TTR) amyloidosis (ATTR). For more information, please visit www.eidostx.com.

Forward-Looking Statements

This release includes forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act. All statements other than statements of historical facts, including statements about the clinical and therapeutic potential of AG10, the completion of our ongoing Phase 2 clinical trial of AG10 in patients with symptomatic ATTR cardiomyopathy and availability of top-line data therefrom, the timing of these events, the indications we intend to pursue and our possible clinical or other business strategies, are forward-looking statements.

Forward-looking statements can be identified by terms such as “believes,” “expects,” “plans,” “potential,” “would” or similar expressions and the

negative of those terms. These forward-looking statements are based on our management’s current beliefs and assumptions about future events and on information currently available to management.

Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These risks include, but are not limited to, risks and uncertainties related to: our limited operating history and historical losses, our liquidity to fund the development of AG10 through current and future milestones, our ability to raise additional funding to complete the development and any commercialization of any of our product candidates, our dependence on the success of our current product candidate, AG10, results from our clinical trials and pre-clinical studies and those of third parties working in the same area as our product candidate and our dependence on third parties in connection with our manufacturing, clinical trials and pre-clinical studies. Additional risks and uncertainties that could affect our future results are

included in the section titled “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2018, which is available on the SEC’s website at www.sec.gov and our website at eidostx.com. Additional information on potential risks will be made available in other filings that we make from time to time with the SEC. In addition, any forward-looking statements contained in this press release are based on assumptions that we believe to be reasonable as of this date. Except as required by law, we assume no obligation to update these forward-looking statements, or to update the reasons if actual results differ materially from those anticipated in the forward-looking statements.

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