The monovalent vaccine, VX-103, ‘significantly exceeded’ FDA criteria for accelerated licensure of influenza vaccines, says the company.
Only half of US adults currently get a seasonal influenza vaccine: and the company points out that vaccine patches would help encourage people to get vaccinated thanks to the convenience of potential self-administration, lack of needles and injection site pain.
Five minute patch time
The trial, conducted in 45 patients aged 18-39, is evaluating H1N1 influenza antigen from Vaxess’s partner, GC Biopharma Corp., delivered via Vaxess's MIMIX Patch.
It is assessing the safety, reactogenicity, tolerability, and immunogenicity profiles for two influenza vaccine dose levels, fractional H1 vaccine dose level 7.5 μg and standard H1 vaccine dose level 15 μg vs placebo.
The MIMIX patches are worn for five minutes. The interim data shows the vaccine patches were well tolerated, with no serious or severe adverse events. The overall rate of reported systemic events was favorable as compared to traditional vaccines delivered by needle and syringe.
Day 57 results show MIMIX-Flu 'significantly' exceeded the 2007 FDA criteria for accelerated licensure of influenza vaccines, with the 15ug and 7.5ug patches leading to seroconversion rates of 85% and 77% respectively along with seroprotection rates of 92% and 92%.
“We evaluated the immune responses relative to two comparators," Michael Schrader, CEO of Vaxess, told us.
"The first is the FDA criteria for accelerated licensure. On day 57, The 15ug patch demonstrated a seroprotection rate of 92%, well above the 70% required, and a seroconversion rate of 85%, well above the 40% required.
“We also compared to serum from the CDC from patients who had received commercial vaccines with the same 2020-2021 H1N1 strain and our data compared favorably. The trial was not powered to show equivalence or superiority, but the trends looked very promising.”
Few side effects
Other promising revelations from the trial include the lack of side-effects from the patch, said Schrader.
“Beyond the strong immune responses, the safety profile of the vaccine was encouraging.
"While we want to caveat this as we only included a single strain (as compared to four in a commercial product), the safety data for the 15 ug patch showed no fever, headache, myalgia, nausea, pain, tenderness, or bruising in any patients.
Vaxess’s phase 1 trial builds on the research the company published in 2021, “Enhancing influenza vaccine immunogenicity and efficacy through infection mimicry using silk microneedles.”
In testing Vaxess’s influenza MIMIX Array Patch system on mice, the company found enhanced humoral and cellular immune responses to the influenza vaccine when compared to receiving the vaccine via intramuscular injection.
The study also showed that sustained release immunization promotes strong and long-lasting anti-influenza antibody responses, and enhanced protection against fatalities.
"This is quite remarkable compared to the same data for commercially licensed vaccines.
“Our phase II trial will include a quadrivalent vaccine and include increased patient numbers to better understand how this promising trend translates.”
The trial will run for 180 days in total, with early animal work suggesting the patch will improve durability of immune responses, continued Schrader.
Vaxess will also evaluate the durability of the immune response for each vaccine dose level, and assess, in at least a subset of samples, the breadth of the influenza A H1 antigen responses.
Vaxess anticipates data publication from the complete Phase 1 trial in the first half of 2023; and is targeting licensure in 2028.