Celltrion's COVID-19 antibody improves outcomes in phase 2

Celltrion’s anti-SARS-CoV-2 antibody has improved outcomes in patients with mild to moderate COVID-19 in a phase 2/3 clinical trial. The Korean biopharma reported lower rates of progression to severe COVID-19, shortened time to clinical recovery and reduced viral load in patients on the drug.

Like anti-SARS-CoV-2 antibodies developed by Eli Lilly and Regeneron, Celltrion’s CT-P59 is designed to improve outcomes in COVID-19 patients by neutralizing the coronavirus. Building on preclinical evidence of efficacy, Celltrion moved CT-P59 into a phase 2/3 clinical trial in October. Top-line data from the 327 subjects enrolled in the first part of the study are now available.

Investigators randomized participants to receive one of two doses of CT-P59, 40 mg/kg or 80 mg/kg, or placebo. The top-line data shared by Celltrion only cover the lower of the two doses of CT-P59.

Celltrion said the 40-mg/kg dose reduced progression to severe COVID-19 by 54% versus placebo at Day 28. In a subgroup of moderate COVID-19 patients aged 50 years and over, the reduction was 68%. More than half of the moderate COVID-19 patients in the study had pneumonia related to the virus.

Patients on the low dose of CT-P59 recovered in 5.4 days, as compared to 8.8 days in the placebo arm. The difference in recovery times was larger in certain subgroups of patients. Subjects suffering from pneumonia recovered in 5.7 days on the low dose of CT-P59, versus 10.8 days for their peers on placebo. In patients aged 50 years and older, the CT-P59 and placebo recovery times were 6.6 days and 13 days, respectively. 

Viral load fell significantly versus placebo at Day 7. Lilly missed the viral load endpoint when it studied its anti-SARS-CoV-2 antibody in mild-to-moderate COVID-19 cases. However, the Lilly trial assessed viral load at Day 11, by when many patients in the placebo cohort may have fought off the virus without pharmacological assistance. 

Lilly and Regeneron have since gone on to receive emergency use authorization for their antibodies. Celltrion sees a market opportunity for another anti-SARS-CoV-2 antibody, though, and is preparing to make enough doses to treat around 2 million patients this year.

If the effects seen in the clinical trial are replicated in the real world, CT-P59 could help lessen the pressure on healthcare systems by preventing patients from needing intensive care and getting them well enough to leave the hospital sooner. Celltrion filed for conditional marketing authorization in Korea late last year and committed to seeking approval in the U.S. and Europe in the coming months.