PERTH, Australia – Starpharma Holdings Ltd. completed a AU$45 million (US$32 million) placement to domestic and international investors that will see it advance its COVID-19 antiviral nasal spray.

The treatment is based on the company’s antiviral dendrimer, SPL-7013, which inactivates viruses by blocking the interaction between viral surface proteins and the human cell receptor proteins. Starpharma’s underlying technology is built around dendrimers, a type of synthetic nanoscale polymer that is highly regular in size and structure.

SPL-7013 is an active component in Starpharma’s existing Vivagel portfolio and is approved for use in products such as a condom lubricant and in a gel used for the treatment and prevention of bacterial vaginosis. The compound has broad-spectrum antiviral and virucidal effects, with activity demonstrated against a range of viruses, including HIV, herpes simplex virus, human papillomavirus, adenovirus, H1N1 influenza virus, hepatitis B virus and Zika virus.

The dendrimer inhibits the infection of cells with the virus, and the finding was validated by replicate testing against Gilead Science Inc.’s remdesivir.

Based on discussions with regulators, Starpharma expects to be able to expedite approval of a SPL-7013 nasal spray by leveraging existing nonclinical and clinical data of Starpharma’s currently approved products.

“Following the emergence of the coronavirus pandemic in February, Starpharma instigated testing of SPL-7013 via a specialist antiviral testing laboratory in Melbourne,” said Starpharma CEO Jackie Fairley. “We are very pleased to find that the compound is highly active against the coronavirus that causes COVID-19.”

The news of the raise comes days after the launch of fellow Aussie biotech Ena Respiratory Ltd., which also has developed a COVID-19 nasal spray that is a pegylated Toll-like receptor (TLR) 2/6 agonist. INNA-051 reduced viral replication by up to 96% in an animal study in ferrets led by Public Health England.

Starpharma’s oversubscribed placement will issue 30 million new shares priced AU$1.50 per share, which represents a 6.5% discount the last closing price of AU$1.60 per share on Sept. 28. A share purchase plan is expected to raise an additional AU$5 million. Bell Potter Securities Ltd. acted as lead manager for the placement.

The funds raised from the placement will be deployed to expedite development of SPL-7013, as well as Starpharma’s pipeline of DEP candidates.

“The funds raised will allow Starpharma to expedite programs across our portfolio, including the novel SPL-7013 COVID-19 nasal spray,” Fairley said.

“They will also allow the company to capitalize on value-adding clinical combinations in our DEP portfolio and to advance development of a number of exciting DEP candidates across radiopharmaceuticals, ADCs and other therapeutic areas,” she said. “Recent transactions, such as the Immunomedics acquisition by Gilead, illustrate the significant potential value of these areas.”

Water-soluble version of Gilead’s remdesivir

Starpharma has also applied its DEP dendrimer drug delivery technology to create a long-acting, water-soluble version of Gilead’s antiviral, remdesivir, which has emergency use authorization from the U.S. FDA to treat patients with severe COVID-19.

The company said that because its formulation is water soluble, it could allow for less frequent dosing than remdesivir and could be used in non-hospital settings such as aged care facilities.

“Given the limited treatment options available for COVID-19 patients, Starpharma has been actively reviewing development programs globally and evaluating where Starpharma’s proprietary DEP technology has potential to improve delivery, expand use or reduce frequency of dosing,” said Fairley.

Starpharma has a partnership with Astrazeneca plc for the use of its DEP drug delivery platform for developing and commercializing a number of Astrazeneca oncology compounds. Because the dendrimer is larger than the small-molecule drug, by attaching to the dendrimer, the drug accumulates in the tumor for a more targeted effect, Fairley said. "All of the drugs we've looked at, including Astrazeneca's drugs, are more efficacious with less toxicity when you put them on a dendrimer."

“While COVID-19 has impacted companies around the world, Starpharma was able to achieve a number of important milestones during the year, including significant progress with our internal clinical-stage DEP assets, with three products now in phase II; advancing multiple new development programs, including antivirals and radiotherapy, in addition to several product launches of Vivagel BV in the U.K., Europe and Asia,” said Fairley.

Starpharma’s stock on the Australian Securities exchange (ASX:SPL) was down 6% from the last day of trading, closing at AU$1.50 per share on Sept. 30.