Eidos Therapeutics, Inc., a clinical stage biopharmaceutical company developing a novel oral therapy to treat transthyretin (TTR) amyloidosis (ATTR), today announced a $64.0 million Series B financing. Proceeds from the financing will be used to advance Eidos' small molecule product candidate, AG10, into Phase 2 clinical trials and to continue preparations for Phase 3 clinical trials. AG10 targets ATTR at its source by potently binding and stabilizing TTR tetramers, the destabilization of which underlies the development of ATTR.

The financing was led by RA Capital Management and included Eidos' parent company, BridgeBio Pharma, in addition to new investors Janus Henderson, Viking Global Investors, Aisling Capital, Perceptive Advisors, Cormorant Asset Management and Amzak Health Investors. The Series B financing brings the total capital raised by Eidos to approximately $91.0 million.

"Our clinical data demonstrate that AG10 has a safe, well-tolerated profile and is able to stabilize 100% of plasma TTR at peak concentrations and provide average levels of stabilization greater than 95% at steady-state," said Neil Kumar, PhD, chief executive officer of Eidos. "Given that increasing levels of stabilization have yielded progressively better clinical results in past trials, our near-complete levels of stabilization suggest that AG10 could be a best-in-class solution. We are targeting ATTR at its source by stabilizing TTR, an approach that is validated by genetics and clinical data."

In connection with the financing, both Rajeev Shah, managing director and portfolio manager at RA Capital, and Eric Aguiar, MD, partner at Aisling Capital, will join Neil Kumar and Hoyoung Huh, MD, PhD, on Eidos' board of directors.

"ATTR diseases are a large and growing unmet need, and together, they represent one of the largest genetically-defined diseases with inadequate standard of care," said Rajeev Shah. "We look forward to working with Eidos' proven management team to bring a disease-modifying treatment for ATTR to market as quickly as possible."

About AG10

AG10 is an orally-administered, small molecule designed to potently and selectively stabilize tetrameric TTR, thereby halting at its outset the series of molecular events that give rise to ATTR. Eidos' approach, based on over 25 years of research, mimics a naturally-occurring genetic rescue mutation that protects high-risk individuals from developing ATTR by stabilizing the TTR tetramer. In fact, the binding of AG10 to tetrameric TTR creates strong molecular bonds at the same locations as the rescue mutation known as T119M, which "super-stabilizes" TTR and has been shown to enhance survival. This specific binding mode underlies AG10's ability at peak blood concentrations to completely stabilize tetrameric TTR and prevent its dissociation into disease-causing TTR monomers in the bloodstream. Given that previous clinical trials in ATTR demonstrate that preventing the generation of TTR monomers from circulating in the bloodstream leads to improved clinical outcomes, Eidos believes that AG10 could be a best-in-class therapy.

About transthyretin amyloidosis (ATTR)

ATTR represents a significant unmet need, with a comparatively large patient population in the context of rare genetic diseases and an inadequate current standard of care. There are three distinct diseases that comprise the ATTR family: wild-type ATTR cardiomyopathy (ATTRwt-CM), mutant ATTR cardiomyopathy (ATTRm-CM), and ATTR polyneuropathy (ATTR-PN). The worldwide prevalence of each disease is approximately 200,000 patients, 40,000 patients and 10,000 patients, respectively, although the cardiomyopathic forms of the disease are thought to be significantly underdiagnosed due to non-specific symptoms and a historical reliance on heart biopsy to make the diagnosis. Eidos believes that improving disease awareness and the introduction of a non-invasive, imaging-based diagnostic scan, coupled with appropriate blood tests, are significantly increasing rates of diagnosis for ATTRwt-CM and ATTRm-CM.

All three forms of ATTR are progressive and fatal, and no disease-modifying therapies have been approved by the FDA. For patients with ATTRwt-CM and ATTRm-CM, symptoms usually manifest later in life (age 50+), with median survival of 3-5 years from diagnosis. ATTR-PN either presents in a patient's early 30s or later (age 50+), and results in a median life expectancy of 5-10 years from diagnosis. Progression of all forms of ATTR causes significant morbidity, impacts productivity and quality of life, and creates a significant economic burden due to the costs associated with progressively greater patient needs for supportive care.

About Eidos Therapeutics

Eidos is a clinical stage biopharmaceutical company focused on addressing the large and growing unmet need in diseases caused by transthyretin (TTR) amyloidosis (ATTR). Eidos seeks to treat this well-defined family of diseases at their collective source by stabilizing TTR, a therapeutic approach that is supported by genetic evidence as well as previous clinical trials. The company's product candidate, AG10, is an orally-administered small molecule designed to potently stabilize TTR, suggesting a best-in-class treatment with the potential to halt the progression of ATTR. The development of AG10 is led by a proven management team who are responsible for developing over 30 molecules through IND applications and more than 10 marketed drugs. Together with patients and physicians, Eidos aims to bring a safe, effective and disease-modifying treatment for ATTR to market as quickly as possible.