SEOUL (Reuters) - South Korea?s Green Cross Corp has sought regulatory approval for Phase II trials of an experimental COVID-19 blood plasma treatment drug, the company said on Wednesday, sending its shares up nearly 10%. Drugmakers worldwide are rushing to develop treatments for the coronavirus, which has killed more than 650,000 and infected more than 16 million since first emerging in China late last year. Green Cross said the clinical trial would review the safety and efficacy of the drug in 60 domestic patients in five hospitals. The firm, which was allowed to skip phase I trials, said its therapy would be the country?s first to enter phase II for COVID-19 plasma treatment. Its intravenously administered medicine, GC5131A, includes hyperimmune immunoglobins produced from processed antibodies in the plasma of recovered coronavirus patients. Green Cross has vowed to donate its locally made treatment to all COVID-19 patients in South Korea, where more than 1,000 recovered patients have come forward to donate plasma. In May, it joined several firms working on plasma-based therapies to develop a treatment for COVID-19 patients. The CoVIg-19 Plasma Alliance for immunoglobulin therapy includes Takeda Pharmaceutical, Biotest AG, CSL Behring, and Octapharma Plasma. Shares of Green Cross rose as much as 10% after the news but closed down 2.3%, lagging a rise of 0.3% in the broader market. (This story refiles to drop outdated material in paragraph 10)