Sorrento Releases Preclinical Data for STI-1499 (COVI-Guard™) and STI-2020 (COVI-AMG™), Potent Neutralizing Antibodies Against SARS-CoV-2

  • In preclinical studies, both STI-1499 and STI-2020 demonstrated potent neutralizing activity against SARS-CoV-2 virus isolates, including the emerging Spike D614G variant virus.
  • Both STI-1499 and STI-2020 demonstrated protective activities against SARS-CoV-2 infection in Syrian golden hamsters.
  • At day 5, STI-2020 at 500 µg reduced virus load in hamster lungs to undetectable levels in 100% of animals tested, whereas STI-1499 at 2,000 µg reduced virus load below the detection limit in 60% of animals tested and showed a 10-fold reduction in the remaining 40% of animals.

SAN DIEGO, CA, USA I September 28, 2020 I Sorrento Therapeutics, Inc. (Nasdaq: SRNE, “Sorrento”) released preclinical data reporting on COVI-GUARD™ (STI-1499) and COVI-AMG™ (STI-2020; Affinity Matured COVI-Guard) neutralizing antibodies (nAbs) against SARS-CoV-2 as well as a D614G virus variant infection in a preprint publication, which can be found at {}. Both STI-1499 and STI-2020 demonstrated potent neutralizing activities against SARS-CoV-2 virus infection in preclinical models. STI-1499 nAb has been cleared by the FDA for a Phase 1 clinical trial in hospitalized COVID-19 patients. STI-2020 is an affinity-matured version of the COVI-GUARD nAb and has demonstrated a greater than 50-fold increase in potency in in vitro experiments.

In preclinical cell-based assay, both STI-1499 and STI-2020 have shown 100% in vitro neutralization of SARS-CoV-2 at concentrations of 6 µg/ml and 78 ng/ml, respectively. The neutralization activity at these concentrations protected against both SARS-CoV-2 and the highly contagious Spike D614G isolate.

Dr. Slobodan Paessler’s laboratory at the University of Texas Medical Branch at Galveston (UTMB) has generated promising preclinical animal data for STI-1499 and STI-2020 nAbs in a Syrian golden hamster model infected with SARS-CoV-2. A few highlights of the data from the most recent STI-2020 study:

  • Hamsters infected with SARS-CoV-2 and then treated with a single dose of 500 µg STI-2020 started gaining weight within 48 hours of STI-2020 administration, as compared to control animals that steadily lost weight for 5 days before recovery.
  • At day 5, STI-2020-treated (500 µg) hamsters had gained 5% weight, versus a weight loss of about 10% for the control animals (15% difference).
  • At day 5, all STI-2020-treated (500 µg) hamsters (5 out of 5 analyzed animals) had undetectable virus load in lungs as compared to the lungs of animals in the control group, where more than 1,000 infectious viral particles per gram of tissue were readily detected.

Based on interspecies allometric scaling methods, the 500 µg single dose of STI-2020 administered to the hamsters in the preclinical studies would be equivalent to a human dose of less than 100 mg of antibody ( In contrast to other currently-used dosing regimens requiring grams of antibody per patient for treating COVID-19, this antibody could be highly potent at a very low dose. COVI-AMG could therefore potentially be administered as a simple and rapid injection to treat COVID-19 patients.

“We believe that the results for STI-1499 and STI-2020 are truly remarkable. Based on the preclinical testing we have conducted to date, STI-2020 is our most promising SARS-CoV-2 antibody so far. The potency of both nAbs and their ability to mitigate SARS-CoV-2 infection from the lungs in a Syrian golden hamster model is very impressive, strongly supporting further development of these antibodies,” stated Dr. Henry Ji, Chairman and CEO of Sorrento. “STI-1499 has been cleared by the FDA for a Phase 1 clinical trial in hospitalized COVID-19 patients. STI-2020 has the potential to be utilized for both early and late therapeutic interventions, as well as for prophylaxis, with the potential of having a low efficacious dose, which could enable efficient manufacturing and ultimately result in higher affordability for patients.”

Sorrento has received FDA clearance for its Phase 1 clinical trial for STI-1499 in hospitalized COVID-19 patients and intends to submit an IND for STI-2020 as soon as possible.

About Sorrento Therapeutics, Inc. 
Sorrento is a clinical stage, antibody-centric, biopharmaceutical company developing new therapies to treat cancers. Sorrento's multimodal, multipronged approach to fighting cancer is made possible by its extensive immuno-oncology platforms, including key assets such as fully human antibodies ("G-MAB™ library"), clinical stage immuno-cellular therapies ("CAR-T", "DAR-T"), antibody-drug conjugates ("ADCs"), and clinical stage oncolytic virus ("Seprehvir®", “Seprehvec™”). Sorrento is also developing potential antiviral therapies and vaccines against coronaviruses, including COVIDTRAP™, ACE-MAB™, COVI-MAB™, COVI-GUARD™, COVI-SHIELD™ and T-VIVA-19™; and diagnostic test solutions, including COVI-TRACK™, COVI-STIX™, COVI-TRACE™ and COVI-AMG™.

Sorrento's commitment to life-enhancing therapies for patients is also demonstrated by our effort to advance a first-in-class (TRPV1 agonist) non-opioid pain management small molecule, resiniferatoxin ("RTX"), and ZTlido® (lidocaine topical system) 1.8% for the treatment of post-herpetic neuralgia. RTX has completed a phase 1B trial for intractable pain associated with cancer and a phase 1B trial in osteoarthritis patients. ZTlido® was approved by the FDA on February 28, 2018.

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SOURCE: Sorrento Therapeutics

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