Ridgeback Aims Antiviral at COVID-19 in Two Phase II Studies


Ridgeback Therapeutics will launch two mid-stage programs assessing the efficacy of its antiviral candidate EIDD-2801 as a treatment for COVID-19.

Last month, Miami-based Ridgeback partnered with Merck to develop EIDD-2801, an investigational, oral form of a potent ribonucleoside analog that inhibits replication of multiple RNA viruses. Early clinical studies showed that EIDD-2801 could be effective against SARS-CoV-2, the virus which causes COVID-19. In the Phase II studies, EIDD-2801 will be administered to patients who are newly diagnosed with COVID-19 and have become symptomatic but remain at home, as well as patients who have been hospitalized with COVID-19. Ridgeback plans to initiate large multi thousand patient confirmatory studies for EIDD-2801 in COVID-19 patients beginning in July. In both studies, patients will receive two doses of the orally-administered drug twice per day for five days.

Wayne Holman, co-founder and scientific advisor of Ridgeback Biotherapeutics, said the goal of the two Phase II studies will be to explore the ability of EIDD-2801 to rapidly eliminate the SARS-CoV2 virus. In preclinical studies of two distinct coronaviruses, SARS-CoV-1 and MERS, EIDD-2801 has been shown to improve pulmonary function, decrease body-weight loss and reduce the amount of virus in the lung.

“If EIDD-2801 is able to eliminate the virus much more quickly than placebo we believe that will be the first indicator that EIDD-2801 could possibly change the course of disease in individual patients, halt the disease in the early stages, potentially reduce the time during which patients are infectious to others and change the course of the pandemic,” Holman said in a statement.

The Phase II studies will be first test of EIDD-2801’s anti-viral activity in humans, the company said.

In May, the company forged an agreement with a subsidiary of pharma giant Merck to develop and commercialize EIDD-2801 and related molecules. The studies announced today confirm the company's ongoing plans for tackling EIDD-2801, and that will continue following the close of the collaboration with Merck.

To ensure that EIDD-2801 is rapidly available if the drug proves to be an effective treatment for COVID-19, Ridgeback has been manufacturing hundreds of thousands of doses. The company said it has plans to produce as many as a million treatment courses by the fall even in advance of definitive clinical data.

“While it is unclear if EIDD-2801 will have the intended efficacy that the Ridgeback team believes is possible, it is imperative to provide immediate and ample supply to the world should the clinical trials be successful,” Wendy Holman, co-founder and chief executive officer of Ridgeback Biopharmaceuticals said in a statement.

COVID-19 has infected more than 8.9 million people across the globe, including 2.2 million in the United States. There have been more than 468,000 deaths associated with the disease, according to the Johns Hopkins COVID-19 dashboard.

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