Sorrento Therapeutics has Received FDA Clearance to Initiate Clinical Trials with a Next Generation mRNA (STI-1557) Vaccine Against Omicron SARS-CoV-2 Virus

San Diego, California, UNITED STATES

  • Modified mRNA sequence of the Spike protein prevents cleavage of the expressed protein, which may potentially result in a cleaner safety profile.
  • Pre-clinical data supporting the investigational new drug application has been published in Molecular Therapy Nucleic Acids, a Cell Press Journal (
  • If approved, this vaccine may provide an important alternative to the vaccines in the U.S. and enable improved access globally in countries like Mexico, Brazil, and China, where mRNA-based vaccines or vaccine boosters are not readily available.
  • Sorrento’s mRNA-based next generation vaccine platform can potentially be adapted rapidly to ever-emerging SARS-CoV-2 variants of concern and useful for other preventive and therapeutic applications to cancer, metabolic and autoimmune diseases.
  • In addition to intramuscular (IM) injections, future studies of the next generation mRNA-based vaccine candidates will be evaluated for administration with the Sofusa MuVaxxTM lymphatic delivery device, which has demonstrated in preclinical models the potential to improve immune response with 10% of the dose required vs. IM injection. The results were published in Journal of Molecular Cell Biology (JMCB) (

SAN DIEGO, Dec. 06, 2022 (GLOBE NEWSWIRE) -- Sorrento Therapeutics, Inc. (Nasdaq: SRNE, "Sorrento") has received clearance from the US FDA to initiate clinical trials with STI-1557, its next generation mRNA vaccine against SARS-CoV-2 Omicron variants. This mRNA vaccine incorporates a mutation in the furin cleavage site that prevents the S1 subunit cleavage from the spike protein from anchoring on the muscle cell membrane. This modification was introduced to prevent the leakage of S1 subunit from the expressed spike protein (S protein) into the blood circulation, which is known in part to potentially cause undesirable side effects in vital organ tissues following administration of the current FDA-approved mRNA vaccines. The mRNA is encapsulated in a Sorrento proprietary lipid nanoparticle formulation (LNP) to protect mRNAs from degradation and enable potent translation of the S protein in host cells after intramuscular (IM) delivery, thus inducing an adaptive immune response.

The preclinical work that supported this investigational new drug application has been published online in Molecular Therapy Nucleic Acids, a Cell Press partner journal. The paper (, titled “Chimeric mRNA-based COVID-19 vaccine induces protective immunity against Omicron and Delta variants,” will appear in print in the December 2022 issue of the journal.

Sorrento plans to pursue more advanced mRNA vaccine strategies in the future with the Sofusa MuVaxx lymphatic delivery system. This proprietary microneedle system delivers vaccines intradermally and, in animal models with an mRNA vaccine candidate, demonstrated improved humoral immunity and superior cellular immunity with 1/10th of the IM dose. This preclinical work has been accepted for publication by the Journal of Molecular Cell Biology (JMCB) (, “Delivering an mRNA vaccine using a lymphatic drug delivery device improves humoral and cellular immunity against SARS-CoV-2.” In these preclinical studies using MuVaxx, immune responses were elicited and maintained at a 10-fold dose reduction compared to traditional IM administration as measured by anti-spike antibodies, cytokine-producing CD8 T cells, neutralizing antibodies. Remarkably, a 4-fold elevated T cell response was also observed in MuVaxx administered vaccination compared to that of IM administered vaccination. This microneedle system delivers the vaccine into at the epidermal/dermal boundary and is virtually pain free. These next generation advances may provide important alternative to the vaccines in the U.S. and enable improved access globally in countries like Mexico, Brazil, and China where mRNA-based vaccines are not readily available.

About Sorrento Therapeutics, Inc. 

Sorrento is a clinical and commercial stage biopharmaceutical company developing new therapies to treat cancer, pain (non-opioid treatments), autoimmune disease and COVID-19. Sorrento's multimodal, multipronged approach to fighting cancer is made possible by its extensive immuno-oncology platforms, including key assets such as next-generation tyrosine kinase inhibitors (“TKIs”), fully human antibodies (“G-MAB™ library”), immuno-cellular therapies (“DAR-T™”), antibody-drug conjugates (“ADCs”), and oncolytic virus (“Seprehvec™”). Sorrento is also developing potential antiviral therapies and vaccines against coronaviruses, including STI-1557, STI-1558, COVISHIELD™, COVIDROPS™ and COVI-MSC™; and diagnostic test solutions, including COVIMARK™.

Sorrento's commitment to life-enhancing therapies for patients is also demonstrated by our effort to advance a TRPV1 agonist, non-opioid pain management small molecule, resiniferatoxin (“RTX”), and SP-102 (10 mg, dexamethasone sodium phosphate viscous gel) (SEMDEXA™), a novel, viscous gel formulation of a widely used corticosteroid for epidural injections to treat lumbosacral radicular pain, or sciatica, and to commercialize ZTlido® (lidocaine topical system) 1.8% for the treatment of postherpetic neuralgia (PHN). RTX has been cleared for a Phase II trial for intractable pain associated with cancer and a Phase II trial in osteoarthritis patients. Positive final results from the Phase III Pivotal Trial C.L.E.A.R. Program for SEMDEXA™, its novel, non-opioid product for the treatment of lumbosacral radicular pain (sciatica), were announced in March 2022. ZTlido® was approved by the FDA on February 28, 2018.

For more information visit

Forward-Looking Statements

This press release and any statements made for and during any presentation or meeting contain forward-looking statements related to Sorrento Therapeutics, Inc., under the safe harbor provisions of Section 21E of the Private Securities Litigation Reform Act of 1995 and subject to risks and uncertainties that could cause actual results to differ materially from those projected. Forward-looking statements include statements regarding the development and prospects of STI-1557; the potential for STI-1557 to have a cleaner safety profile; the potential use of STI-1557 as an alternative to the vaccines in the U.S.; the potential for STI-1557 to result in improved access to vaccines globally, including in countries like Mexico, Brazil and China, the potential of the mRNA-based next general platform to be adapted rapidly to ever-emerging SARS-CoV-2 variants of concern and its usefulness for other preventative, and therapeutic applications to cancer, metabolic and autoimmune diseases; and Sorrento’s plans to pursue more advanced mRNA vaccine strategies in the future. Risks and uncertainties that could cause our actual results to differ materially and adversely from those expressed in our forward-looking statements, include, but are not limited to: risks related to Sorrento's technologies and prospects, including, but not limited to risks related to safety and efficacy of STI-1557 and seeking regulatory approval for STI-1557; clinical development risks, including risks in the progress, timing, cost, and results of clinical trials and product development programs; risks related to Sorrento’s planned studies with STI-1557; risk of difficulties or delays in obtaining regulatory approvals; risks that clinical study results may not meet any or all endpoints of a clinical study and that any data generated from such studies may not support a regulatory submission or approval; risks that prior test, study and trial results, including those for STI-1557 and MuVaxx, may not be replicated in continuing or future studies and trials; risks of manufacturing and supplying drug product; risks related to leveraging the expertise of its employees, subsidiaries, affiliates and partners to assist Sorrento in the execution of its product candidates’ strategies; risks related to the global impact of COVID-19; and other risks that are described in Sorrento's most recent periodic reports filed with the Securities and Exchange Commission, including Sorrento's Annual Report on Form 10-K for the year ended December 31, 2021 and subsequent Quarterly Reports on Form 10-Q filed with the Securities and Exchange Commission, including the risk factors set forth in those filings. Investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release, and we undertake no obligation to update any forward-looking statement in this press release except as required by law.

Media and Investor Relations
Contact: Brian Cooley

Sorrento® and the Sorrento logo are registered trademarks of Sorrento Therapeutics, Inc.

G-MAB™, DAR-T™, Seprehvec™, SOFUSA™, COVISHIELD™, COVIDROPS™, COVI-MSC™, COVIMARK™ and Fujovee™ are trademarks of Sorrento Therapeutics, Inc.

SEMDEXA™ (SP-102) is a trademark of Semnur Pharmaceuticals, Inc. A proprietary name review by the FDA is planned.

ZTlido® is a registered trademark owned by Scilex Pharmaceuticals Inc.

All other trademarks are the property of their respective owners.

©2022 Sorrento Therapeutics, Inc. All Rights Reserved.