Strong data for pegylated interferon lambda, Eiger Biopharmaceuticals Inc.’s experimental COVID-19 treatment, boosted the company stock (NASDAQ:EIGR) 23% on Feb. 9 as the company continues to seek regulatory approval. That approval path is blocked as interferon lambda is not currently approved by the U.S. FDA for any use. In October, the company said it would not submit emergency authorization use request after feedback from the FDA.