Nasal Spray for Protection Against COVID-19 Inhibits Infection of Host Cells by SARS‑CoV-2

An antiviral dendrimer, SPL7013 that has been repurposed as an antiviral nasal spray for protection against COVID-19 has demonstrated potent antiviral activity against SARS-CoV-2 in clinical studies.

Starpharma Holdings Limited’s (Melbourne, Australia) proprietary antiviral dendrimer, SPL7013, has broad spectrum antiviral and virucidal effects, with activity demonstrated against a range of viruses. SPL7013 inactivates viruses by blocking the interaction between viral surface proteins and the human cell receptor proteins. In clinical studies, SPL7013 was found to inhibit infection of host cells by SARS-CoV-2 when it was applied to the cells either before or after exposure to the virus. In an assay to detect virucidal activity, SPL7013 also rendered SARS-CoV-2 inactive and prevented infection when it was mixed with the virus prior to adding to cells.


The data generated indicate that SPL7013 acts early in the SARS-CoV-2 replication cycle. When SPL7013 was added to cells before or at various stages of the virus replication lifecycle after infection with SARS-CoV-2, no infectious virus was detected, regardless of the initial time of addition of SPL7013. This finding was in contrast to other antivirals, remdesivir and hydroxychloroquine, for which infectious virus was detectable at all times of addition, when tested in the same assay.

These data are consistent with SPL7013 inhibiting the initial stages of SARS-CoV-2 attachment and entry into cells, and inactivating the virus, as has been demonstrated for other viruses such as HIV. This mechanism of action, high selectivity, and the fact that it is a large dendrimer molecule that is not systemically absorbed, make SPL7013 well-suited to being applied topically as a nasal spray to help prevent SARS-CoV-2 infection. SPL7013 could also be applied via other routes of administration, such as ocular, nebulized or injection. The SPL7013 nasal spray has the potential to complement vaccine strategies to further reduce risk by preventing acquisition and transmission of SARS-CoV-2, and reducing disease progression due to ongoing viral replication in mild forms of COVID-19. A cost-effective and readily available product to help prevent SARS-CoV-2 infection would play an important role in reducing transmission for the broader population and especially for frontline workers in the health, aged care and travel industries.

“We are pleased to provide an update on the progress with development of the SPL7013 nasal spray,” said Dr. Jackie Fairley, Starpharma CEO. “The potent activity of SPL7013 in SARS-CoV-2, its action early in the replication cycle and its selectivity are all positive product features. Whilst effective vaccines will be central to the fight against COVID-19, other preventative measures will continue to be important to reduce the risk of transmission and exposure to SARS-CoV-2. Our strategy for the product includes leveraging Starpharma’s vast body of existing technical data and existing regulatory approvals for SPL7013, to fast-track the regulatory and commercialization pathways to have the product ready for market as soon as possible.”

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