Arcturus’ COVID Vaccine Moves to Phase 2 Trial in Singapore
On December 28th, Arcturus Therapeutics announced that it had received authorization from the Singapore Health Sciences Authority to begin Phase 2 clinical trials of their vaccine candidate, ARCT-021, against COVID-19. In the Phase1/2 trial, 100% of patients injected with a single dose or prime-boost regimens produce antibodies against the SARS-CoV-2.
Almost 82 million people have tested positive for COVID-19 worldwide, and over 1.79 million people have died since the beginning of the pandemic. Although, it is believed that these numbers are an undercount of the real extent of the pandemic. Several vaccine candidates are in clinical trials all over the world. In the US, two vaccines were approved in December 2020. Both vaccines, one developed by Pfizer-BioNTech and one developed by Moderna, use mRNA technologies, and they are over 90% effective. However, both require two doses, and the Pfizer-BioNTech vaccine requires ultra-low temperature storage, which complicates distribution. Vaccines that require a single dose, and don’t require specialized equipment are necessary to accomplish a global vaccination effort.
ARCT-021 and Arcturus Therapeutics
San Diego-basedArcturus Therapeutics is a clinical-stage company specializing in RNA-based medicines. Its leading vaccine candidate, known as ARCT-021, combines two proprietary technologies, the self-transcribing and replicating RNA (STARR) technology and the lipid-mediated nanoparticle delivery system (LUNAR). mRNA vaccines work by giving cells the instructions to produce a viral protein. The body then learns to produce antibodies against this protein, which can protect when the real virus enters the body. In a presentation earlier this month, Arcturus presented preclinical data showing their STARR technology produced around 30X more viral proteins when compared to normal mRNA. This allowed the company to use very low doses of ARCT-021 and still stimulate the immune system and the production of antibodies after a single administration of the vaccine.
In a Phase1/2 clinical trial that included 106 participants, all patients vaccinated with 7.5ug single dose and the ones who received 5ug and subsequent prime-boost regimens developed neutralizing antibodies against SARS-CoV-2. Additionally, the vaccine was well tolerated as no serious adverse events were observed. This could suggest that a single dose could be enough to provide protection. Arcturus also developed a novel lyophilization process technology, which would allow the vaccine to be distributed using a normal freezer, and they are currently collecting data on the stability of the vaccine at room temperature. Based on this data, the Singapore Health Sciences Authority has authorized the start of Phase 2 clinical trials to evaluate single dose and prime-boost regimens in up to 600 participants.
“We are pleased to advance ARCT-021 into a Phase 2 study based upon our promising Phase 1/2 data, which continues to support the potential for Arcturus’ STARR™ self-replicating mRNA technology to provide a highly effective, and differentiated clinical profile, including a single-dose regimen,” said Steve Hughes, M.D., Chief Development Officer of Arcturus. “The Phase 2 study will enable selection of the optimal ARCT-021 vaccination regimen for Phase 3 registrational studies. We look forward to obtaining interim Phase 2 data in early 2021 providing support for the anticipated initiation of a global Phase 3 study in Q2 2021.”