Celltrion Inc, a South Korean drugmaker, revealed on Monday positive results for its experimental antibody COVID-19 treatment that it said was safe and slowed the treatment period by nearly five days in Phase 3 global clinical trials.

The trials, which involved 1,315 participants, have taken place since January in 13 countries, including in South Korea, the US, Spain and Romania, Celltrion said in a statement.

The treatment reduced severe symptoms of COVID-19 in more than 70 percent of patients, including the high-risk group with underlying conditions. It also cut the recovery period by 4.9 days, the company said.

In February South Korea, offered conditional approval to the antibody treatment, making it the first locally made coronavirus treatment in the country to win such approval. The company said it would seek full authorization based on the trial results.

Celltrion shares rose as much as 5.6 percent in Monday morning trade, compared with a 0.3 percent drop in the wider market.