Merck is paying $425 million for the private company, in addition to extra payments for regulatory milestones and sales. Merck has built out its portfolio of COVID-19 medicines through a series of deals in recent months, including the acquisition of Australian drugmaker Themis and a partnership with Ridgeback Biotherapeutics LP.
OncoImmune recently announced positive interim data from a phase 3 trial of its leading therapeutic candidate, CD24F, for patients with severe and critical COVID-19.
The data show that the therapy, which is administered as an injection, increased the likelihood of symptom improvement in serious COVID-19 cases and also reduced the risk of respiratory failure and death, said Roger Perlmutter, who heads research at Merck.
He added that CD24F could potentially complement dexamethasone, a generic steroid that is the current standard of care for the most serious COVID-19 cases. The steroid was used to treat U.S. President Donald Trump for COVID-19 in October.
Merck is aiming to develop the manufacturing capacity needed to produce the therapy at scale, which could take weeks to months.
CD24F was originally developed to treat graft versus host disease (GVHD) for patients with leukemia who received stem cell transplants. OncoImmune has initiated phase 3 studies for the drug in GVHD.
Merck is also developing two potential vaccines that are still in early stages of development and an antiviral treatment called molnupiravir.
Pfizer Inc and BioNTech Inc filed for regulatory authorization of their vaccine candidate on Friday after advanced studies show it was highly effective in preventing COVID-19.
(Reporting by Carl O'Donnell, Editing by Rosalba O'Brien)
By Carl O'Donnell