SAN FRANCISCO—A few days ago, Eidos Therapeutics, Inc., a clinical stage biopharmaceutical company developing a novel oral therapy to treat transthyretin (TTR) amyloidosis (ATTR), announced a $64 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.
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 million. In addition to 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.
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). All three forms of ATTR are progressive and fatal, and no disease-modifying therapies have been approved by the FDA. 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.
“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.”
AG10 targets ATTR at its source by potently binding and stabilizing TTR tetramers, the destabilization of which underlies the development of 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. 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.
“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 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.”