Merck agreed to acquire Cidara Therapeutics for $9.2 billion to secure CD388, a late‑stage, long‑acting, strain‑agnostic antiviral designed to prevent symptomatic influenza in high‑risk individuals. CD388 combines a small‑molecule neuraminidase inhibitor with an antibody Fc fragment to extend half‑life, and it carries Breakthrough and Fast Track designations from the FDA. Merck framed the deal as a strategic expansion of its respiratory portfolio and a response to persistent influenza burden in older and immunocompromised populations. The Phase III ANCHOR study is underway; earlier Phase IIb NAVIGATE data met primary and secondary prevention endpoints, bolstering Merck’s willingness to pay a premium for near‑commercial assets in respiratory disease. Clarification: long‑acting antivirals aim to provide season‑long protection with a single dosing regimen, which could shift prevention strategies away from annual vaccinations in certain high‑risk cohorts.