I-Mab Reports Positive Interim Analysis from Phase 2/3 Study of its GM-CSF Antibody Plonmarlimab (TJM2) to Treat Patients with Severe COVID-19

by Kashmiira Nayar


I-Mab announces positive interim results from its U.S. phase 2/3 study of plonmarlimab for the treatment of cytokine release syndrome (CRS) in patients with severe COVID-19. Data showed a higher rate of patients without mechanical ventilation, a lower mortality rate, and reduced recovery and hospitalization durations. The treatment also resulted in reduced pro-inflammatory cytokines and chemokines critically involved in CRS, and was well tolerated, promising the potential for a new treatment option.

I-Mab announces positive interim data from its U.S. phase 2/3 study of plonmarlimab, developed to target a particular cytokine critical in acute and chronic inflammation, for the treatment of cytokine release syndrome (CRS) in patients with severe COVID-19.

CRS, or cytokine storm, is a pathological surge of circulating inflammatory cytokines caused particularly by the Delta variant of the COVID-19 virus, resulting in higher mortality. Plonmarlimab is expected to be efficacious in treating and preventing CRS by inhibiting human granulocyte-macrophage colony-stimulating factor (GM-CSF).

The ongoing study is assessing the safety, efficacy and effects on cytokine of GM-CSF antibody after a single 6mg/kg dose of plonmarlimab vs. placebo, and is one of the first studies to do so. Interim analysis showed that treatment with plonmarlimab resulted in a higher mechanical ventilation free (MVF) rate in patients, lower mortality rate, higher recovery rates as well as reduced recovery and hospitalization durations, as compared to placebo. Patients treated with plonmarlimab demonstrated reduced plasma levels of pro-inflammatory cytokines and chemokines critically involved in CRS, and no significant safety concerns were observed.

“Plonmarlimab has shown very promising results from the interim data analysis in our phase 2/3 trial, and we intend to continue advancing the study in the U.S. at this critical juncture of the COVID-19 pandemic and continue exploring other clinical opportunities associated with CRS,” commented Dr. Joan Shen, CEO of I-Mab.

About Plonmarlimab
Plonmarlimab (or TJM2) is an internally discovered neutralizing antibody against human GM-CSF, a cytokine that plays a crucial role in the pathogenesis and disease progression of multiple autoimmune conditions. Plonmarlimab binds to GM-CSF and prevents it binding to its receptor, thereby inhibiting inflammatory responses leading to tissue inflammation and damage.

About I-Mab
I-Mab is global clinical-stage biotech company focused on discovering, developing and soon commercializing innovative therapies targeting immuno-oncology and autoimmune diseases. For more information, visit http://ir.i-mabbiopharma.com and follow I-Mab on LinkedInTwitter, and WeChat.

(Source: I-Mab Biopharma, 11th August 2021)


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