OncoImmune

The company's lead product was CD24Fc (also known as SACCOVID), a first-in-class recombinant fusion protein that targets the innate immune system to regulate host inflammatory responses to tissue injuries. This therapeutic had potential applications across various conditions, including graft-versus-host disease (GVHD), cancer, and autoimmune diseases. OncoImmune conducted multiple clinical trials for CD24Fc, including a Phase IIa trial for the prevention of acute GVHD in leukemia patients undergoing hematopoietic stem cell transplantation. In 2020, amidst the global pandemic, the company initiated a Phase III clinical trial (SAC-COVID) to evaluate CD24Fc's efficacy in treating hospitalized patients with severe and critical COVID-19. The trial showed that CD24Fc significantly reduced the risk of death or respiratory failure by over 50% and increased the probability of clinical improvement by 60% compared to a placebo.

Following the positive Phase III results, Merck & Co. announced its acquisition of OncoImmune in November 2020 for an upfront payment of $425 million in cash, with shareholders eligible for additional milestone-based payments. The acquisition was centered on accelerating the global development and manufacturing of CD24Fc as a potential COVID-19 therapy. As part of the agreement, OncoImmune's other pipeline assets, including ONC-392, a next-generation anti-CTLA-4 antibody, were spun out into a new entity called OncoC4, in which Merck became a minority shareholder. Drs. Liu and Zheng continue their work at OncoC4, leading the development of new cancer immunotherapies.