Sorrento Reports Promising Results With a Universal Chimeric mRNA COVID-19 Vaccine That Elicits Potent Neutralizing Antibodies and Protection Against Omicron (BA.1 and BA.2) and Delta Variants

Sorrento scientists have perfected the expression of the spike protein to potentially improve the safety profile of the COVID-19 mRNA vaccines by incorporating a furin cleavage site mutation to prevent leakage of S1 subunit into the blood circulation targeting vital organ tissues with ACE2 receptors for the spike proteins that may in part cause the undesirable side effects.Sorrento’s designer mRNA vaccine, utilizing a chimeric mRNA that incorporates the Delta receptor binding domain (RBD) into the Omicron spike protein, provided strong, broad-spectrum protection against both BA.1 and BA.2 sublineages of Omicron, and Delta variant in immunized animals.Sorrento intends to develop and seek EUA approval of this next-generation mRNA vaccine in Mexico and other developing countries. SAN DIEGO, March 20, 2022 (GLOBE NEWSWIRE) — Sorrento Therapeutics, Inc. (Nasdaq: SRNE, “Sorrento”), a clinical and commercial stage biopharmaceutical company developing new therapies to treat cancer, pain and COVID-19, announced today the publication of a preprint entitled “Chimeric mRNA based COVID-19 vaccine induces protective immunity against Omicron and Delta.” The preprint can be viewed at: https://www.biorxiv.org/content/10.1101/2022.03.04.483032v2 Compared to the original SARS-CoV-2 strain, the Omicron variant contains more than 30 additional mutations within the spike protein coding sequence, 15 of which reside in the receptor binding domain (RBD) that serve to increase the affinity of the Omicron spike binding to the human ACE2 receptor. These changes result in enhanced transmissibility and breakthrough cases in the presence of antibodies induced by vaccination with the wild-type SARS-CoV-2 spike mRNA vaccines. During the past two years, Sorrento scientists explored various strategies to develop mRNA vaccines that can potentially provide broad and effective protection against predominant SARS-CoV-2 variants of concern (VOCs) as well as potential future variants. The newly designed mRNA vaccine incorporates a mutation in the furin cleavage site that prevents the S1 subunit cleavage from the spike protein anchored on the muscle cell membrane. This modification is introduced to prevent the leakage of S1 subunit from the expressed spike 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 EUA-approved mRNA vaccines. Serum collected from Omicron-specific mRNA vaccine immunized animals provided superior protection against the infection of Omicron strain, including the BA.1, BA.1+R346K and the more recent BA.2 sublineage that is battering many regions of the world, demonstrating this newly designed mRNA vaccine could induce potent production of Omicron-specific neutralization antibodies (nAbs) in vivo. Even in animals previously vaccinated with the original WA1 spike mRNA, a single booster with Omicron-specific mRNA still provided excellent protection against Omicron infection. When immunized with a designer chimeric Delta RBD-Omicron mRNA vaccine, there was a significant increase in the nAb titer against the Delta variant in addition to strong nAbs against the Omicron variants. This novel designer chimeric mRNA vaccine may offer a powerful strategy to develop mRNA vaccines with universal protection against SARS-CoV-2 and its major VOCs. “The concept of a universal mRNA vaccine is still very appealing for at least two reasons. One is that the virus could continue accumulating more mutations to eventually nullify the effectiveness of marketed mRNA vaccines. Secondly, a universal mRNA vaccine against COVID-19 is much needed worldwide, especially in developing countries,” stated Dr. Henry Ji, Chairman and CEO of Sorrento. “We have established a subsidiary company – Sorrento Therapeutics Mexico – with the intention to develop and commercialize rapidly a next generation universal mRNA vaccine against COVID-19 in Mexico and expand further into the vast Latin America markets”. 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 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 Abivertinib, COVI-AMG™, COVISHIELD™, COVI-MSC™ and COVIDROPS™; and diagnostic test solutions, including COVITRACK™ and COVIMARK™. 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 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 post-herpetic 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. SEMDEXA announced highly statistically significant positive top-line results from its Phase III Pivotal Trial C.L.E.A.R Program for its novel, non-opioid product for the treatment of lumbosacral radicular pain (sciatica). ZTlido® was approved by the FDA on February 28, 2018. For more information visit www.sorrentotherapeutics.com 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 Sorrento’s universal chimeric mRNA COVID-19 vaccine candidate (the “chimeric mRNA vaccine”), including the potential for it to provide strong, broad-spectrum protection against SARS-CoV-2 and its current and future variants of concern (VOCs); the safety profile and effectiveness of the chimeric mRNA vaccine, including the potential for preventing undesirable side effects in vital organ tissues as a result of leakage of the S1 subunit into the blood circulation; the potential for the chimeric mRNA vaccine to induce potent production of neutralizing antibodies against SARS-CoV-2, including against the Omicron (including the BA.1, BA.1+R346K and BA.2 subvariants) and Delta variants; Sorrento’s plans and expectations to develop and seek emergency use authorization for the chimeric mRNA vaccine in Mexico and other developing countries, including in Latin America; and Sorrento’s position in the COVID-19 vaccine industry. 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 and its subsidiaries’, affiliates’ and partners’ technologies and prospects and collaborations with partners, including, but not limited to risks related to conducting additional studies and seeking regulatory approval for the chimeric mRNA vaccine, including the timing for receipt of any such approval; conducting and receiving results of clinical studies; clinical development risks, including risks in the progress, timing, cost, and results of clinical studies and product development programs; 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 may not be replicated in future studies and trials; risks related to leveraging the expertise of its employees, subsidiaries, affiliates and partners to assist the company in the execution of its COVID-19 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: Dorman FollowwillEmail: [email protected] Sorrento® and the Sorrento logo are registered trademarks of Sorrento Therapeutics, Inc. G-MAB™, DAR-T™, Seprehvec™, SOFUSA™, COVI-AMG™, COVISHIELD™, COVIDROPS™, COVI-MSC™, COVITRACK™ and COVIMARK™ are trademarks of Sorrento Therapeutics, Inc. SEMDEXA™ is a trademark of Semnur Pharmaceuticals, Inc. 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.