Several biotech and healthcare stocks posted notable gains in after-hours trading on Friday, driven by regulatory developments, financing updates, and investor sentiment.Atossa Therapeutics, Inc. (ATOS) rose 12.98% to $0.69, up$0.080 after announcing that the U.S. Food and Drug Administration's Office of Orphan Products Development granted Orphan Drug Designation to (Z)-endoxifen for the treatment of Duchenne muscular dystrophy. The designation marks a significant milestone for the company's pipeline.Immu ...