Jean-Pierre Sommadossi
Analyst · Morgan Stanley
Thank you, John. Let's now move to Slide 18. Hepatitis E virus or HEV is in an acute and a chronic liver disease. In developing countries, genotype 1 and 2 are most prevalent and the virus is transmitted primarily through contaminated water and mostly cause epidemics of acute self-limiting viral hepatitis. In developed countries, genotype 3 is predominantly transmitted primarily through contaminated food such as undercooked meat. This can cause chronic hepatitis in immunocompromised patients and can progress to cirrhosis within 3 to 5 years, which is much far more aggressive than what is seen with hepatitis C or hepatitis B. With no approved therapies for HEV, there is a significant unmet need for a treatment option. Moving to Slide 19. In recent years, with the increasing number of patients who are immunocompromised, which include solid organ transplant recipients, hematopoietic stem cell transplant recipients, patients with hematologic malignancies such as multiple myeloma, there have been a growing incidence of chronic HEV infection in U.S. and Europe. In the absence of any approved therapies for HEV, the standard of care includes reducing immunosuppression and/or ribavirin administration, which both presents challenges. On Slide 20, each year in the U.S. and Europe, about 3% of approximately 450,000 patients who have these underlying medical conditions are at risk to develop chronic HEV. We estimate that the unmet need for this patient population represents a market opportunity between $750 million to $1 billion per year. And obviously, this will follow on orphan designation. On Slide 21, let's now review data supporting the selection of AT-587, our lead product candidate, a potential first-in-class direct-acting antiviral treatment option for chronic HEV. As you see on this slide, in vitro and in vivo activity of bemnifosbuvir was shown against hepatitis C. However, the more potent in vitro activity of AT-587, combined with the positive PK data, which we'll discuss next, led us to select AT-587 as a lead product candidate. The in vitro data on this slide shows the potent nanomolar antiviral activity of AT-587 against HEV genotype 3 and to remain also active against clinical ribavirin resistance-associated substitutions or RAS. As noted earlier, ribavirin is off-label for the treatment -- is used off-label for the treatment of HEV. On Slide 22, we observed that the in vivo single-dose PK studies in rats and monkeys, AT-587 achieved high plasma concentration of the active triphosphate metabolite surrogate, which were comparable to those obtained with bemnifosbuvir. On Slide 23, of particular importance, we also demonstrated that AT-587 efficiently converted to its active triphosphate metabolite in human hepatocytes, which is the site of viral replication in HEV infection. To date, AT-587 has a clean preclinical safety profile, positioning this product candidate as a first-in-class direct-acting antiviral for chronic HEV. I will now turn the call over to Andrea to discuss Atea financials.