The U.S. Food and Drug Administration (FDA) granted fast track designation for a “self-amplifying mRNA vaccine candidate” against bird flu. Arcturus Therapeutics Holdings Inc., a commercial messenger RNA medicine company focused on the development of infectious disease vaccines and opportunities within liver and respiratory rare diseases, today announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation for the self-amplifying mRNA (sa-mRNA) vaccine candidate, ARCT-2304, designed for active immunization to protect against disease caused by influenza A H5N1 subtype contained in the vaccine,” a news release read. “This designation recognizes the potential of ARCT-2304 as an innovative approach to address unmet medical needs for the prevention of disease caused by pandemic influenza A virus H5N1, a significant global health risk. The Phase 1 clinical study initiated in November 2024,” it continued. BREAKING: FDA Fast Tracks Self-Amplifying mRNA Bird Flu Injection WHAT THE HELL IS GOING ON AT ⁦@FDA⁩?#stopthemadness https://t.co/Xz4MIaumHN — Brian Tyson, MD (@btysonmd) April 11, 2025 “The designation is designed to expedite the development and review process, providing several benefits, including enhanced communication with the FDA and eligibility for priority review, and the possibility of a rolling review,” the news release continued. “We are pleased to receive Fast Track Designation from the FDA for ARCT-2304,” said Joseph Payne, President and CEO of Arcturus Therapeutics. “We remain steadfast in our commitment to the U.S. government to develop safe and effective STARR® next-generation mRNA vaccines to protect U.S. citizens from future pandemic threats. This designation from the FDA is an important step forward in our mission to provide protective solutions for global health crises,” Payne added. Arcturus Therapeutics' self-amplifying mRNA (sa-mRNA) vaccine, ARCT-2304, for H5N1 influenza granted FDA Fast Track Designation. Phase 1 study began Nov 2024 to combat pandemic flu risks. pic.twitter.com/MOEH6hZSdJ — Camus (@newstart_2024) April 11, 2025 Per MarketWatch: Arcturus, a San Diego medicines and vaccines company, in November launched a Phase 1 clinical study, supported in whole with federal funds from the Department of Health and Human Services. Outbreaks of avian influenza A H5N1, also known as bird flu, have been decimating U.S. poultry flocks since 2022, and while the federal government currently assesses the risk from H5N1 viruses to the general U.S. population as low, it has committed hundreds of millions of dollars to push development of vaccines for a potential pandemic. BREAKING: FDA Fast Tracks Gates Foundation & BARDA-Funded Experimental Self-Amplifying mRNA Bird Flu Injection ARCT-2304 replicates inside your cells like a synthetic virus—producing toxic antigens and potentially shedding for an unknown duration. This risks irreversible… pic.twitter.com/99075yAfjW — Nicolas Hulscher, MPH (@NicHulscher) April 11, 2025 From Drug Topics: As of March 6, 2025, the drug is still in phase 1 clinical trials, but interim data is expected in the second half of 2025. Investigators of the study aimed to determine the safety and immune response of 3 different dose levels for the proposed vaccine. The objectives included evaluating the safety and reactogenicity and describing the immune responses, measured by hemagglutination inhibition and neuraminidase enzyme-linked lectin antibody responses. The results will be compared to a current licensed influenza vaccine to choose the most optimal dose and schedule.2,3 The investigators state that patients will receive either 2 doses of the vaccine or 1 dose of a licensed vaccine and 1 dose of a placebo. Patients will keep a daily diary for 7 days after each vaccination, provide blood samples at each visit in the clinic, and comply with the study visits and procedures, according to the clinical trial information.3 Furthermore, there will be 2 parts: one for 120 young adults (aged 18 years to 59 years) and one for 80 older adults (aged 60 years to 80 years). Participants will receive 1 of 3 doses of the proposed vaccine or the control vaccines, and the vaccination schedule will be randomized between 1 of 2. The primary objectives included the evaluation of safety and immune responses of the 3 different dose levels and the 2 different vaccination schedules.3,4 “Clinically validating our low-dose STARR mRNA technology in H5N1 flu is a crucial step towards pandemic preparedness,” Payne said in a news release.4 “Our team is working diligently with our partners, BARDA and CSL, in the United States and globally in this effort.” ARCT-2304 is designed to make many copies of mRNA within the host cell after injection to enhance the expression of HA and NA antigens, which will allow for a lower dose than other mRNA vaccines. Screening for the phase 1 study began in November 2024, with the first patient inoculated in December 2024.4