RedHill Biopharma's Opaganib Inhibits COVID-19 Variants in Preclinical Study

Opaganib strongly inhibits Beta (South African) and Gamma (Brazilian) COVID-19 variants,further supporting its antiviral activity

Opaganib's unique,orally-administered,host-targeted,dual antiviral and anti-inflammatory approach to combatting COVID-19 is also expected to maintain effect against other emerging variants,including the Delta (Indian) variant

Completion of opaganib's global fully enrolled 475-patient Phase 2/3 study in hospitalized patients with COVID-19 expected in the coming weeks

TEL AVIV,Israel and RALEIGH,N.C.,June 28,2021 --RedHill Biopharma Ltd. (Nasdaq: RDHL) ("RedHill" or the "Company"),a specialty biopharmaceutical company,today announced preliminary results of a new preclinical study showing potent inhibition of COVID-19 variants of concern by opaganib (Yeliva®,ABC294640)[1].

Opaganib,a leading novel investigational oral pill in development for the treatment of COVID-19,is a unique host-targeted,dual antiviral and anti-inflammatory drug that acts on the cause and effect of COVID-19. It exerts its antiviral effect by selectively inhibiting sphingosine kinase-2 (SK2),a key enzyme produced in human cells that can be recruited by the virus to support its replication. Following the recently presented positive U.S. Phase 2 study data,opaganib's global 475-patient Phase 2/3 study in hospitalized patients with COVID-19 is fully enrolled and is expected to be completed in the coming weeks.

Working with the University of Louisville Center for Predictive Medicine,opaganib was studied in a 3D tissue model of human bronchial epithelial cells (EpiAirway™) to evaluate the in vitro efficacy of opaganib in inhibiting the Beta (South African) and Gamma (Brazilian) SARS-CoV-2 variants. Preliminary results showed potent inhibition of both the Beta and Gamma variants by opaganib at non-cytotoxic doses.

"The results we have seen with opaganib so far are exciting," said William Severson,Ph.D.,Director of Shared Resources for the Center for Predictive Medicine,University of Louisville."They provide further evidence in support of opaganib's antiviral capabilities and highlight opaganib's potential as an orally-administered treatment for COVID-19 and its continuously emerging variants."

"Opaganib inhibits an enzyme in the COVID-19 patients' cells called sphingosine kinase-2,which the SARS-CoV-2 virus can recruit in order to replicate," said Reza Fathi,PhD.,RedHill's Senior VP,R&D. "Opaganib's dual antiviral and anti-inflammatory mechanism of action is independent of mutations in the spike protein. This means we expect opaganib to similarly work against other emerging COVID-19 variants,including the Delta (Indian) variant. Moreover,we are looking forward to seeing the top-line clinical data from the global Phase 2/3 study which is expected to be completed in the coming weeks."

The global Phase 2/3 study of opaganib in COVID-19 has previously received four independent DSMB recommendations to continue following unblinded safety reviews and a futility review. Additionally,an evaluation of the blinded blended intubation and mortality rates to date was encouraging as compared to reported rates of mortality from large platform studies such as RECOVERY,and other studies in similar patient populations[2].

About Opaganib (Yeliva®,ABC294640)

Opaganib,a new chemical entity,is a proprietary,first-in-class,sphingosine kinase-2 (SK2) selective inhibitor,with dual anti-inflammatory and antiviral activity,that is host-targeted and is therefore expected to be effective against emerging viral variants.

Opaganib is being evaluated as a treatment for COVID-19 pneumonia in a global Phase 2/3 study,which recently completed enrollment,and has demonstrated positive safety and efficacy signals in preliminary top-line data from the 40-patient U.S. Phase 2 study.

Opaganib demonstrated potent inhibition of viral replication against SARS-CoV-2,the virus that causes COVID-19,in an in vitro model of human lung bronchial tissue. Additionally,preclinical in vivo studies have demonstrated opaganib's potential to ameliorate inflammatory lung disorders,such as pneumonia,and has shown decreased fatality rates from influenza virus infection and ameliorated Pseudomonas aeruginosa-induced lung injury by reducing the levels of IL-6 and TNF-alpha in bronchoalveolar lavage fluids[3].

Opaganibhas also received Orphan Drug designation from the U.S. FDA for the treatment of cholangiocarcinoma and is being evaluated in a Phase 2a study in advanced cholangiocarcinoma and in a Phase 2 study in prostate cancer.

The ongoing studies with opaganibare registered onwww.ClinicalTrials.gov,a web-based service by the U.S. National Institute of Health,which provides public access to information on publicly and privately supported clinical studies.

About RedHill Biopharma

RedHill Biopharma Ltd. (Nasdaq: RDHL) is a specialty biopharmaceutical company primarily focused on gastrointestinal and infectious diseases. RedHill promotes the gastrointestinal drugs,Movantik® for opioid-induced constipation in adults[4],Talicia® for the treatment of Helicobacter pylori (H. pylori) infection in adults[5],and Aemcolo® for the treatment of travelers' diarrhea in adults[6]. RedHill's key clinical late-stage development programs include: (i) RHB-204,with an ongoing Phase 3 study for pulmonary nontuberculous mycobacteria (NTM) disease; (ii) opaganib (Yeliva®,ABC294640),a first-in-class SK2 selective inhibitor targeting multiple indications with positive Phase 2 COVID-19 data and an ongoing Phase 2/3 program for COVID-19 and Phase 2 studies for prostate cancer and cholangiocarcinoma ongoing; (iii) RHB-107 (upamostat),a serine protease inhibitor in a U.S. Phase 2/3 study as treatment for symptomatic COVID-19,and targeting multiple other cancer and inflammatory gastrointestinal diseases; (iv) RHB-104,with positive results from a first Phase 3 study for Crohn's disease; (v) RHB-102 (Bekinda®),with positive results from a Phase 3 study for acute gastroenteritis and gastritis and positive results from a Phase 2 study for IBS-D; and (vi) RHB-106,an encapsulated bowel preparation. More information about the Company is available at www.redhillbio.com / https://twitter.com/RedHillBio.

This press release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements may be preceded by the words "intends," "may," "will," "plans," "expects," "anticipates," "projects," "predicts," "estimates," "aims," "believes," "hopes," "potential" or similar words. Forward-looking statements are based on certain assumptions and are subject to various known and unknown risks and uncertainties,many of which are beyond the Company's control and cannot be predicted or quantified,and consequently,actual results may differ materially from those expressed or implied by such forward-looking statements. Such risks and uncertainties include the delay in last patient visit and top-line data from the Phase 2/3 COVID-19 study for opaganib,that the Phase 2/3 COVID-19 study for opaganib may not be successful and,even if successful,such study and results may not be sufficient for regulatory applications,including emergency use or marketing applications,and that additional COVID-19 studies for opaganib are likely to be required by regulatory authorities to support such potential applications and the use or marketing of opaganib for COVID-19 patients,that opaganib will not be effective against emerging viral variants,as well as risks and uncertainties associated with (i) the initiation,timing,progress and results of the Company's research,manufacturing,preclinical studies,clinical trials,and other therapeutic candidate development efforts,and the timing of the commercial launch of its commercial products and ones it may acquire or develop in the future; (ii) the Company's ability to advance its therapeutic candidates into clinical trials or to successfully complete its preclinical studies or clinical trials (iii) the extent and number and type of additional studies that the Company may be required to conduct and the Company's receipt of regulatory approvals for its therapeutic candidates,and the timing of other regulatory filings,approvals and feedback; (iv) the manufacturing,clinical development,commercialization,and market acceptance of the Company's therapeutic candidates and Talicia®; (v) the Company's ability to successfully commercialize and promote Movantik®,Talicia® and Aemcolo®; (vi) the Company's ability to establish and maintain corporate collaborations; (vii) the Company's ability to acquire products approved for marketing in the U.S. that achieve commercial success and build and sustain its own marketing and commercialization capabilities; (viii) the interpretation of the properties and characteristics of the Company's therapeutic candidates and the results obtained with its therapeutic candidates in research,preclinical studies or clinical trials; (ix) the implementation of the Company's business model,strategic plans for its business and therapeutic candidates; (x) the scope of protection the Company is able to establish and maintain for intellectual property rights covering its therapeutic candidates and commercial products and its ability to operate its business without infringing the intellectual property rights of others; (xi) parties from whom the Company licenses its intellectual property defaulting in their obligations to the Company; (xii) estimates of the Company's expenses,future revenues,capital requirements and needs for additional financing; (xiii) the effect of patients suffering adverse events using investigative drugs under the Company's Expanded Access Program; and (xiv) competition from other companies and technologies within the Company's industry. More detailed information about the Company and the risk factors that may affect the realization of forward-looking statements is set forth in the Company's filings with the Securities and Exchange Commission (SEC),including the Company's Annual Report on Form 20-F filed with the SEC on March 18,2021. All forward-looking statements included in this press release are made only as of the date of this press release. The Company assumes no obligation to update any written or oral forward-looking statement,whether as a result of new information,future events or otherwise unless required by law.

Company contact:

Adi Frish

Chief Corporate & Business Development Officer

RedHill Biopharma

+972-54-6543-112

adi@redhillbio.com

Media contacts:

U.S.: Bryan Gibbs,Finn Partners

+1 212 529 2236

bryan.gibbs@finnpartners.com

UK: Amber Fennell,Consilium

+44 (0) 7739 658 783

fennell@consilium-comms.com

[1] Opaganib is an investigational new drug,not available for commercial distribution.

[2] Based on preliminary blinded blended data from 463 patients. The Company did not conduct a head-to-head comparison study in the same patient population. The theoretical comparison between the global Phase 2/3 study with opaganib and reported rates of mortality from large platform studies such as RECOVERY,and other studies in similar patient populations,serves as a general benchmark and should not be construed as a direct and/or applicable comparison as if the Company conducted a head-to-head comparison study.

[3] Xia C. et al. Transient inhibition of sphingosine kinases confers protection to influenza A virus infected mice. Antiviral Res. 2018 Oct; 158:171-177. Ebenezer DL et al. Pseudomonas aeruginosastimulates nuclear sphingosine-1-phosphate generation and epigenetic regulation of lung inflammatory injury. Thorax. 2019 Jun;74(6):579-591.

[4] Full prescribing information for Movantik® (naloxegol) is available at: www.Movantik.com.

[5] Full prescribing information for Talicia® (omeprazole magnesium,amoxicillin and rifabutin) is available at: www.Talicia.com.

[6] Full prescribing information for Aemcolo® (rifamycin) is available at: www.Aemcolo.com.

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