With its acquisition of privately held Oncoimmune Ltd. for an up-front $425 million in cash, Merck & Co. Inc. ups its COVID-19 game with CD24Fc, a recombinant fusion protein targeting the innate immune system that is faring well in treating pandemic patients.

Oncoimmune’s lead product is being evaluated in two phase III programs – one to determine its ability to protect against immune destruction in severe and critical COVID-19 patients and another in leukemia patients prone to acute graft-vs.-host disease after receiving allogeneic hematopoietic stem cell transplantation.

The immunomodulator’s phase III COVID-19 trial began in April by treating hospitalized patients at the University of Maryland Baltimore Medical Center. Recently revealed top-line results showed a 60% better chance over placebo in achieving clinical recovery (p=0.005), with median time to recovery of six days vs. 10 days for placebo.

The randomized, double-blind, placebo-controlled trial was initiated in 17 medical centers nationwide in April and is enrolling severe and critical COVID-19 patients that either require supplemental oxygen support or high flow oxygen non-invasive ventilation, in addition to ICU patients requiring invasive mechanical ventilation. The study was set to enroll more than 270 patients, and enrollment closed in September.

CD24Fc is a biologic that fortifies the innate immune checkpoint against excessive inflammation caused by tissue injuries.

The deal

Kenilworth, N.J.-based Merck, using a subsidiary, will acquire all Oncoimmune’s outstanding shares. Oncoimmune shareholders could receive sales-based payments and payments based on achieving certain regulatory milestones.

Before the acquisition is completed, Oncoimmune also said it will spin out to a new entity some rights and assets unrelated to the CD23Fc program. That new entity will be owned by Oncoimmune shareholders while Merck becomes a minority shareholder. It also brings a $50 million investment to sweeten the pot.

Oncoimmune’s portfolio

Only two months ago, Rockville, Md.-based Oncoimmune completed a $56 million financing from a series B equity round co-led by HM Capital and a blue-chip investor. Existing investors 3E Bioventures Capital and Kaitai Capital, as well as additional new investors GBA Fund and GF Xinde, also joined the round. The company said it would use the proceeds to support its therapeutic programs in late-stage clinical trials and to expand its product pipeline.

In September, Oncoimmune dosed the first patient in its phase Ia/Ib trial testing ONC-392, an anti-CTLA4 antibody, as a single agent and in combination with anti-PD-(L)1 standard-of-care therapy in non-small-cell lung cancer.

The company is led by chairman and founder Yang Liu, who is also director for the Center for Cancer and Immunology Research at the Children’s National Medical Center in Washington. He is also a professor of cancer biology and transplantation immunology in the pediatrics department of the Children’s National Medical Center and George Washington University.

Merck’s COVID-19 coalition

Merck is also developing COVID-19 therapies with privately held Ridgeback Biotherapeutics LP and with nonprofit scientific research organization IAVI.

Miami-based Ridgeback is in a small-molecule alliance with Merck to develop EIDD-2801, an oral form of a ribonucleoside analogue that inhibits replication of multiple RNA viruses, including SARS-CoV-2. The collaboration launched in May. Merck, through a subsidiary, gained exclusive worldwide rights to develop and commercialize EIDD-2801 and related molecules while Ridgeback received an undisclosed up-front payment, specified milestones and a share of the net proceeds of EIDD-2801 and related molecules, if approved. Merck is responsible for clinical development, regulatory filings and manufacturing. Enrollment for a phase II COVID-19 study began in July.

In late October, IAVI and the Serum Institute of India Pvt. Ltd., of Pune, India, said they entered an agreement with Merck to develop SARS-CoV-2 neutralizing monoclonal antibodies co-invented by IAVI and Scripps Research to address COVID-19. If the cross-reactive SARS-CoV-2 neutralizing antibody candidates being advanced through the partnership are efficacious in clinical trials, either as a single antibody or a potential combination of both candidates, Merck will lead commercialization in developed countries. Serum Institute will lead global manufacturing as well as commercialization in low- and middle-low-income countries, including India.