Investigational anti-SARS-CoV-2 molecules show efficacy in pre-clinical studies

Sorrento Therapeutics, Inc. announced it completed pre-clinical testing of a batch of the STI-4398 (COVIDTRAP) protein, reporting it was able to neutralise SARS-CoV-2 (the coronavirus causing the COVID-19 pandemic) and inhibit the virus infecting angiotensin converting enzyme 2 (ACE2)-expressing cells.

According to the enterprise since the start of 2020 it has been using a multi-pronged strategy to search for and develop potent antidotes to the SARS-CoV-2 virus of COVID-19. They announced in May that they had produced a neutralising antibody, called STI-1499, that demonstrated 100 percent inhibition of SARS-CoV-2 virus infection in an in vitro infection experiment at a low concentration. The company believes STI-1499 could be a potent antidote for COVID-19, after its safety and efficacy are demonstrated in pre-clinical and clinical studies.

The organisation also announced in March that it had designed and produced its STI-4398 product candidate, an ACE2-Fc fusion protein developed to act as a decoy receptor for the Spike protein of the SARS-CoV-2 virus, which bind to ACE2 receptors on human respiratory epithelial cells to initiate infection. Sorrento now reports that in an in vitro assay, STI-4398 completely inhibited the ability of SARS-CoV-2 virus to infect African green monkey kidney epithelial cells (VERO/E6 cells) expressing ACE2.

The company has discussed with the US Food and Drug Administration (FDA) the development of this drug candidate and received guidance on the path forward to a clinical trial for STI-4398 as both a potential treatment of infected patients and a potential prophylactic treatment for COVID-19.

“STI-4398 COVIDTRAP protein and STI-1499 neutralising antibody have shown efficacy in an in vitro cellular infection model for SARS-CoV-2 established in our laboratory and these results justify now the progression into animal studies. We are planning to submit all pre-clinical data for scientific publication in the next two to three months,” stated Dr Slobodan Paessler, Professor in the Department of Pathology, John S. Dunn Distinguished Chair in Biodefense and Scientific Director of the Animal Biosafety Laboratory 3 at the Galveston National Laboratory at the University of Texas Medical Branch, whose lab conducted the in vitro viral infection tests for both STI-1499 and STI-4398.

Dr Henry Ji, Chairman and Chief Executive Officer of Sorrento Therapeutics, added: “Our researchers and manufacturing scientists have worked tirelessly to bring COVIDTRAP through pre-clinical profiling to the brink of clinical trials.  We look forward to evaluating the safety and efficacy of STI-4398 in clinical trials and, assuming receipt of all requisite approvals, ultimately manufacturing this potentially life-saving compound as a potent anti-COVID-19 antidote available in the armamentarium of physicians fighting the COVID-19 pandemic.”