BEIJING, Dec 13 (Reuters) - China"s Brii Biosciences (2137.HK) said on Sunday lab studies showed that its COVID-19 antibody cocktail retained activity against the Omicron variant, although one of the antibodies showed a substantial drop in activity when tested alone. Test details for the dual-antibody treatment, which last week became the first approved COVID-19 antibody cocktail in China, would not be available until publication in a scientific journal, but results from three independent labs showed similar pattern, Brii chief executive Hong Zhi said on Monday. read more Although no purchase order for the treatment has been announced, the firm was able to secure manufacturing capacity of 1 million doses for 2022 and 2023 each, Hong said in an investor call, adding it already has about 80,000 doses available in its inventory. Hong said the firm hoped to receive stockpiling orders for the antibody combination. "Those are very important for us as a small company to really manage our cash flow at the same time addressing a public pandemic." The firm, yet to disclose any in-house production capacity for the drug, is partnering with WuXi Biologics (2269.HK) for manufacturing.