Zelicapavir

Gilead Sciences\' decision on whether to persevere with obeldesivir will determine whether the company has a place in the respiratory syncytial virus antiviral race.\n Gilead Sciences has blamed the low rate of respiratory syncytial virus (RSV) infections last season for ending two midstage trials of obeldesivir.The pharma had been evaluating the antiviral drug in two RSV studies in adults and children, respectively. However, the company “recently terminated the two trials following lower than expected RSV incidence rates during the most recent RSV season in the Northern Hemisphere, which made it difficult to determine meaningful rates of symptom reduction, a primary endpoint of the study,” Gilead confirmed to Fierce Biotech.The decision to stop the studies “did not reflect any safety or efficacy concerns,” added Gilead, which will share data already accumulated from the trials to “inform a discussion on potential next steps.”With no other RSV candidates listed in Gilead’s pipeline, the decision on whether to persevere with obeldesivir in this indication will determine whether the company still has a place in the RSV antiviral race.It’s not the first time low infection rates have derailed a trial of obeldesivir. Back in 2023, Gilead ended a phase 3 study of the antiviral for COVID-19 based on “lower-than-expected COVID-19 incidence rates and related hospitalizations.”A clinical trial of obeldesivir in Marburg virus, a severe disease that can have a high death rate, is ongoing, Gilead pointed out. Preclinical research has suggested that the antiviral could prove effective against the virus. The RSV market is dominated by vaccines like Pfizer’s Abrysvo and GSK’s Arexvy and Moderna’s mRESVIA along with Sanofi and AstraZeneca’s prophylactic antibody Beyfortus. Merck’s own antibody option Enflonsia has recently secured approval.Meanwhile, a number of companies have demonstrated clinical success with their antiviral candidates in recent months, including Shionogi’s S-337395 and Enanta Pharmaceuticals’ zelicapavir. Despite the dominance of vaccines, Enanta has previously explained that it sees an ongoing need for antivirals in both the pediatric and adult populations, noting babies and children will go on to get RSV infection after protection wanes and that there is low vaccine use in adults. 

WATERTOWN, Mass.--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today announced that data from the Company’s Phase 2 study of zelicapavir in young children infected with respiratory syncytial virus (RSV) will be available as an E-Poster at the 43rd Annual Meeting of the European Society for Paediatric Infectious Diseases (ESPID) 2025, being held May 26-30, 2025 at the Bucharest International Conference Centre in Bucharest, Romania and online. The E-Poster will highlight results from a Phase 2 study of zelicapavir, an oral, non-nucleoside small-molecule RSV-replication-inhibitor (N-protein), which were announced in December 2024, and include new data on the population PK/PD and time to viral load negativity. E-Poster Title: “Antiviral Treatment of RSV in Children: Virology and PK Results of a Randomized Double-Blind Placebo-Controlled International Trial of Zelicapavir (EDP-938)” E-Poster Number: ID 1767 Date and Time: Available starting on May 26, 2025, at 8:00 a.m. Eastern European Summer Time/ 1:00 a.m. Eastern Daylight Time E-Poster Location: Level 0, Main Floor or on the conference portal and the conference app Presenter: John DeVincenzo, M.D. A copy of the E-Poster will be available on Enanta’s website here. The scientific program for ESPID 2025 can be found here. About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs with an emphasis on indications in virology and immunology. Enanta’s clinical programs are currently focused on respiratory syncytial virus (RSV) and its earlier-stage immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, including KIT and STAT6 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of one of the leading treatment regimens for curing chronic hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information.