Enanta Doses First Patient in Global Phase 2b/3 RESOLVE Trial of Zelicapavir for RSV in High-Risk Adults
Enanta Pharmaceuticals, Inc. (NASDAQ: ENTA), a clinical-stage biotechnology company based in Watertown, Massachusetts, announced on October 26 that the first patient has been dosed in RESOLVE, its global Phase 2b/3 clinical trial of zelicapavir in adult outpatients at high risk of severe outcomes from respiratory syncytial virus (RSV) infection. Topline data from the Phase 2b portion of the study are expected in 2027.
RESOLVE is a randomized, double-blind, placebo-controlled, multicenter global trial enrolling adult outpatients who test positive for RSV and have had respiratory tract infection symptoms for no more than three days, with at least one risk factor: age 75 or older, chronic obstructive pulmonary disease (COPD), or congestive heart failure. Patients receive oral zelicapavir 800 mg or placebo once daily for seven days and are evaluated for 28 days thereafter. The primary endpoint is the time to complete resolution of all 13 RSV symptoms as measured by the RiiQ tool, with hospitalization rate as a key secondary endpoint. The Phase 2b portion will include a minimum of 200 patients, while the Phase 3 portion is expected to enroll approximately 660 patients.
Scott T. Rottinghaus, M.D., Enanta's Chief Medical Officer, said the RESOLVE population builds on the company's earlier Phase 2 RSVHR study, in which the high-risk HR3 population — patients with congestive heart failure, COPD, or age 75 or older — saw a 6.7-day benefit in time to complete symptom resolution versus placebo, and an RSV-related hospitalization rate of 0% compared with 5% on placebo. He noted that no approved RSV antiviral therapies are currently available. Juan Antonio Carmona Herrera, M.D., a principal investigator in RESOLVE and president of C&A Clinical Trials Corp, said an effective antiviral could change how RSV is managed by directly targeting the virus.
According to the company, zelicapavir inhibits the RSV N-protein with nanomolar activity against both RSV-A and RSV-B, has received Fast Track designation from the U.S. Food and Drug Administration (FDA), and has been well tolerated in more than 700 people to date. Enanta is also running the pediatric Phase 2b trial LOTUS, with both Phase 2b readouts expected in 2027. Citing Centers for Disease Control and Prevention (CDC) figures, the company said RSV accounts for up to 6.8 million outpatient visits, approximately 370,000 hospitalizations and 24,000 deaths annually in the United States, including up to 180,000 hospitalizations among adults over 50. The company cautioned that the statements are forward-looking and that trial outcomes and timelines are uncertain.
Source: GSM · USA (original Chinese edition)
Photo: 图：呼吸道合胞病毒（RSV）扫描电子显微图。图片：美国国家过敏与传染病研究所 NIAID，CC BY 2.0，经 Wikimedia Commons。Photo: Scanning electron micrograph of human respiratory syncytial virus (RSV). Image: National Institute of Allergy and Infectious Diseases (NIAID), CC BY 2.0, via Wikimedia Commons.
