South Korean biotechnology firm Hyundai Bioscience Co. said Tuesday that the combination of its oral antiviral candidate and dexamethasone showed high efficacy in treating COVID-19 during animal testings.

The company is currently re-purposing niclosamide-based CP-COV03 as a potential treatment for the COVID-19 virus. The investigative drug's indication also includes influenza.

Citing the result of the latest animal testing, Hyundai Bioscience said use of both CP-COV03 and dexamethasone resulted in efficacy against COVID-19 that is 2.1 times higher than using dexamethasone alone.

Dexamethasone is a corticosteroid that is used in a wide range of conditions for its anti-inflammatory and immunosuppressant effects.

"Dexamethasone can come with side effects such as reducing the activity of the immune system. That is why it is important to find a medication that be combined to bring about right anti-viral effect," Jin Keun-woo, a Hyundai Bioscience official, said.

"CP-COV03 will be the best mate for dexamethasone."

To expand the indication, the company has won approval from local drug authorities to conduct phase one clinical trial of CP-COV03 in 18 adult patients.

Currently, Remdesivir, which is developed by Gilead Sciences Inc., and dexamethasone are used to treat critically ill COVID-19 patients.

Other COVID-19 antiviral oral drug candidates currently under development are Pfizer Inc.'s PF-07321332 and Merck's MK-4482. (Yonhap)