Humanigen has reported positive data from the first clinical use of lenzilumab, its humaneered anti-human granulocyte macrophage-colony stimulating factor (GM-CSF) monoclonal antibody, in 12 Covid-19 patients.

Patients treated with lenzilumab showed rapid clinical improvement with a median time to recovery and discharge of five days and 100% survival to the data cut-off date.

Furthermore, they demonstrated rapid improvement in oxygenation, temperature, inflammatory cytokines and key hematological parameters consistent with improved clinical outcomes.

Humanigen CEO Dr Cameron Durrant said: “It is extremely encouraging to see this initial group of high-risk patients with severe and critical Covid-19 pneumonia show clinical improvement on lenzilumab, and at the data cut-off point, 11 of them discharged from the hospital.

“All 12 patients had at least one risk factor associated with poor outcomes, such as age, smoking history, cardiovascular disease, diabetes, chronic kidney disease, chronic lung disease, high BMI, and elevated inflammatory markers, with several patients having multiple such risk factors.”

Patients who were hospitalised in the Mayo Clinic system showed severe or critical pneumonia as a result of Covid-19 and were viewed as being at high risk of further disease progression.

They needed oxygen supplementation and had elevation in at least one inflammatory biomarker before receiving lenzilumab.

Mayo Clinic Medicine professor Dr Zelalem Temesgen said: “Lenzilumab use was associated with improved clinical outcomes and oxygen requirement, with no reported mortality.

“Based on the pathophysiology of cytokine storm following SARS-CoV-2 infection, along with work conducted at Mayo Clinic on GM-CSF depletion in CAR-T therapy, lenzilumab may offer a rational approach to ameliorate the consequences of cytokine storm in Covid-19.”