VIRALEZE™ Antiviral Nasal Spray

VIRALEZE™ has been developed by Starpharma, a world leader in the development of new medical products based on its proprietary dendrimer technology, as an antiviral nasal spray that is intended to provide a moisturising and protective barrier in the nose. VIRALEZE™ also contains SPL7013, which has been shown in laboratory studies to inactivate a broad spectrum of respiratory/cold viruses.

The nasal cavity has been shown to be a primary site where respiratory viruses, including cold viruses and SARS-CoV-2 (the virus that causes COVID-19), become established, before spreading in the body (Hou et al., 2021).

SPL7013 was originally developed by Starpharma for its antiviral activity and has been shown to block a broad-spectrum of viruses in nonclinical in vitro and in vivo studies (Bernstein et al, 2003; Jiang et al, 2005; Gong et al, 2005; Lackman-Smith et al, 2008; Tyssen et al, 2010; Telwatte et al, 2011; Romanowski et al, 2021).

Starpharma subsequently generated and published laboratory data showing that SPL7013 also inactivates >99.9% of coronavirus SARS-CoV-2 (Paull et al., 2021a).

Starpharma has also published data demonstrating the protective efficacy of VIRALEZE™ antiviral nasal spray against SARS-CoV-2 challenge in vivo in a humanised mouse model of coronavirus infection. The study results showed that VIRALEZE™ administered nasally reduced viral load by >99.9% (vs. saline control) in the lungs and trachea of animals challenged with SARS-CoV-2. The protective effects of VIRALEZE™ against SARS-CoV-2 in animals are consistent with the previously reported in vitro virucidal activity of SPL7013, which reduces infectious SARS-CoV-2, including the Delta variant, by >99.9% within 30 seconds of exposure. The results of the in vivo study (conducted at The Scripps Research Institute) have been published in the peer-reviewed journal, Viruses, in a special issue titled, Medical Interventions for Treatment and Prevention of SARS-CoV-2 Infections (Paull et al., 2021b).

SPL7013 has also been shown in laboratory studies conducted at the Scripps Research Institute to inactivate several SARS-CoV-2 “Variants of Concern”, including the Alpha, Beta, Gamma, Delta and Omicron variants, with testing planned for other variants as they emerge and become available.

In addition, Starpharma announced that SPL7013 was shown in laboratory studies to block human respiratory syncytial virus (HRSV), and to block infection by other pandemic coronaviruses (SARS-CoV, MERS-CoV) and influenza viruses. On 18 May 2022, Starpharma reported new virucidal data for SPL7013 against influenza virus A and B, in laboratory studies. SPL7013 achieved 95% and 99.7% reduction in viral infectivity against influenza virus A and B, respectively.

SPL7013 is a patented, precisely designed large negatively charged molecule that has been shown to not pass into the bloodstream following topical application to mucosal epithelial surfaces. In VIRALEZE™, SPL7013 is intended to form a barrier locally at site of application in the nasal cavity to physically trap and thereby inactivate respiratory viruses.

Starpharma was awarded development funding for the development and commercialisation of VIRALEZE™ by the Australian Government’s Medical Research Future Fund Biomedical Translation Bridge Program. 

VIRALEZE™ is registered for sale in more than 30 countries, including in Europe, Asia, and the Middle East. VIRALEZE™ launched in the UK through LloydsPharmacy, as announced on 25 March 2021 and then in Europe via Starpharma's webstore, as announced on 6 May 2021. VIRALEZE™ has also launched in Vietnam as announced on 3 December 2021. Starpharma is also progressing regulatory activities for a number of markets, including Australia, with the intention of rolling it out across other markets. VIRALEZE™ is not approved for sale or supply in Australia.

SPL7013 is also included in products registered in >45 countries and available for sale in the UK, Europe, Japan, South East Asia, Australia and New Zealand. 

VIRALEZE™ mechanism of action

VIRALEZE™ is applied to the nasal cavity where respiratory viruses that cause colds, flu, and more severe respiratory illness, first attach and start to multiply. 

VIRALEZE™ provides a moisturising and protective barrier in the nose and contains SPL7013, which physically traps and inactivates viruses. SPL7013 has been shown in laboratory studies to inactivate viruses (Paull et al., 2021a). 

SPL7013 acts by trapping viruses, and blocking the interaction between virus attachment proteins, or “spikes”, and the human cells viruses are seeking to infect. 


“Spike” proteins on the surface of viruses that come into contact with VIRALEZE™ are physically trapped by SPL7013. This interaction is irreversible (“virucidal”) and blocked viruses can no longer infect cells.

The “blocked” viruses are then cleared naturally through the nasal mucus.

The mechanism of action of SPL7013 appears to be not adversely impacted by mutations in the spike proteins of SARS-CoV-2 that make the virus more infectious, as occurred for the Delta strain. Instead, the mutations that make the virus interact more readily with cells and therefore more infectious, may make it more susceptible to trapping and blocking by SPL7013.

VIRALEZE™ well tolerated in multiple dose clinical study

Starpharma has completed a randomised double-blind, placebo-controlled, safety, tolerability, and absorption study of VIRALEZE™ in 40 healthy volunteers, who used the product four times a day for 14 days (as announced on 17 August 2021). The product was well tolerated with no notable or serious adverse events reported, and no participants discontinued product use. The study also confirmed that SPL7013 was not absorbed into the bloodstream following repeated nasal application. This finding is consistent with previous extensive nonclinical and clinical data showing lack of systemic absorption of SPL7013 following topical application to mucosal membranes.


Hou, Y.J. et al. SARS-CoV-2 reverse genetics reveals a variable infection gradient in the respiratory tract. Cell, 2020, 182(2), 429-446.e14. 
Paull, J.R.A. et al. Virucidal and antiviral activity of astodrimer sodium against SARS-CoV-2 in vitro. Antiviral Research, 2021(a), 191, 105089.
Paull, J.R.A. et al. Protective effects of astodrimer sodium 1% nasal spray formulation against SARS-CoV-2 nasal challenge in K18-hACE2 mice. Viruses, 2021(b), 13, 1656.


For more information: 

Download ASX Announcement: SPL7013 in VIRALEZE™ virucidal against Omicron (PDF, 331KB) - 1 March 2022

Download ASX Announcement: VIRALEZE™ sales and distribution in Saudi Arabia and GCC (PDF 274KB) - 3 February 2022

Download ASX Announcement: VIRALEZE™ antiviral nasal spray registered in Saudi Arabia (PDF 239KB) - 14 December 2021

Download ASX Announcement: VIRALEZE™ successfully launched in Vietnam (PDF 215KB) - 13 December 2021

Download ASX Announcement: VIRALEZE™ distribution agreement and launch in Vietnam (PDF 224KB) - 3 December 2021

Download ASX Announcement: VIRALEZE™ registered in Vietnam with launch this week (PDF 214KB) - 1 December 2021

Download ASX Announcement: VIRALEZE™ distribution and supply to Vietnam (PDF 224kb) - 26 October 2021

Download ASX Announcement: VIRALEZE ADMENTA agreement - supplementary information (PDF 204kb) - 12 October 2021

Download ASX Announcement: VIRALEZE™ launch in ADMENTA Italia Group pharmacies in Italy (PDF 435kb) - 8 October 2021

Download ASX Announcement: VIRALEZE Protects Against SARS-CoV-2 in Challenge Model (PDF 347kb) - 23 August 2021

Download ASX Announcement: VIRALEZE™ well tolerated in multiple dose clinical study (PDF 219kb) - 17 August 2021

Download ASX Announcement: VIRALEZE SPL7013 virucidal (>99.99%) against Delta variant (PDF 520kb) - 27 July 2021

Download ASX Announcement: VIRALEZE UK update (PDF 320kb) - 21 June 2021

Download ASX Announcement: VIRALEZE SPL7013 virucidal against multiple COVID variants(PDF 520kb) - 18 June 2021

Download ASX Announcement: VIRALEZE antiviral nasal spray registered for sale in India (PDF 520kb) - 11 June 2021

Download ASX Announcement: VIRALEZE SPL7013 highly active in UK variant of coronavirus (PDF 520kb) - 1 June 2021

Download ASX Announcement: VIRALEZE™ launches in Europe (PDF 218kb) - 6 May 2021

Download ASX Announcement: VIRALEZE™ now launched by LloydsPharmacy in the UK (PDF 224kb) - 30 March 2021

Download ASX Announcement: VIRALEZE™ to be launched with LloydsPharmacy in the UK (PDF 241kb) - 25 March 2021

Download ASX Announcement: SPL7013 active against other pandemic coronaviruses (PDF 418kb) - 3 March 2021

Download ASX Announcement: VIRALEZE™ antiviral nasal spray registered in Europe (PDF 226kb) - 23 February 2021

Download full announcement: VIRALEZE COVID-19 nasal spray study to commence in January (PDF 71kb) - 22 December 2020

Download full announcement: VIRALEZE™ COVID-19 nasal spray to be ready for market Q1CY21 (PDF 113kb) – 10 December 2020

Download full announcement: SPL7013 shows potent antiviral activity in RSV expanding use for nasal spray (PDF 95kb) – 19 November 2020

Download full announcement: SPL7013 COVID-19 nasal spray virucidal against SARS-CoV-2 (PDF 183kb) – 14 September 2020

Download full announcement: SPL7013 nasal spray for COVID-19 – development update (PDF 267kb) – 25 August 2020

Download ASX Announcement: SPL7013 shows significant activity against SARS-CoV-2 (coronavirus) (pdf file, 69kb) – 15 April 2020