Phase 3 results prove efficacy of Celltrion Covid treatment

Celltrion’s Covid-19 treatment Regkirona can reduce the progression rate of the disease by 70 percent, according to Phase 3 clinical trial results.

On Monday, the bio company shared top line results of Regkirona’s Phase 3 trials — the last round of clinical trials required for the drug.

Conducting Phase 3 trials and submitting the results was the condition Korean drug regulators put up when it granted Regkirona emergency use approval in February. It remains the only Korea-made Covid-19 treatment that has received the nod so far, and has treated more than 4,500 patients in the country.

Celltrion said the Phase 3 trials were successful in that all four indicators showed statistically meaningful results in terms of efficacy and safety, based on comparisons between groups injected with Regkirona and those injected with a placebo.

Phase 3 clinical trials began in 13 countries, including Korea, in January. A total of 1,315 patients with light and moderate symptoms took part. Classified into two groups, the volunteers were injected once with either Regkirona or the placebo drug in April.

The most important data set in proving efficacy was the progression rate, which refers to speed at which a patient's condition worsens.

In general, Regkirona reduced the progression rate by 70 percent compared to the placebo group. For high-risk patients aged over 50 years or those with underlying diseases, the progression rate dropped slightly more, by 72 percent.

The treated group also showed faster recovery.

While patients injected with the placebo took an average 13.3 days to recover, those treated with Regkirona recovered in 8.4 days, a 4.9-day difference. Among high-risk patients, the Regkirona-treated group recovered in 9.3 days, around 4.7 days faster than the placebo group’s 14 days.

In regard to safety, the number of patients experiencing side effects was similar among the Regkirona group and the placebo group. Symptoms reported by the volunteers in the trials were light, Celltrion said. Of 652 Regkirona-treated volunteers, the one case that resulted in hospitalization after the injection was due to a skin rash. The patient has fully recovered.

In May, Celltrion and the Korea Disease Control and Prevention Agency announced that tests showed Regkirona had neutralizing effects on several Covid-19 variants as well, including those first identified in New York and Nigeria.

Whether Regkirona is effective at treating coronavirus mutations was not discussed in Monday’s announcement.

“During the mass-scale clinical trial, we injected patients as soon as they arrived so there wasn’t a system that allowed us to check beforehand if the affecting virus was a Covid-19 variant or not,” said Kim Sung-hyun, a Celltrion director, during an online press conference, Monday.

“Once we have more data in July, we’ll be able to tell what effect Regkirona has on the mutations.”

More detailed data sets from the Phase 3 trials will be shared later this month, the company said, adding it plans to present the results at the European Congress of Clinical Microbiology & Infectious Diseases, which starts on July 9.

Since Regkirona is already widely used in local hospitals, the new results won’t change its status in Korea. But Celltrion expects Phase 3 results to help accelerate authorization in other regions like Europe and United States.

In February, the company said it is in talks to potentially export Regkirona to seven or eight countries.

“We’re in the last stage of discussing possible exports,” Kim said. “Proving efficacy and safety in large scale trials is always important to sell a drug overseas, let alone a Covid-19 treatment. We’re hoping Phase 3 clinical trial results will have a good influence.”

BY SONG KYOUNG-SON [song.kyoungson@joongang.co.kr]