Gennova's mRNA vaccine to come in powder form, stay stable at 2-8°C

Gennova has also got permission for phase-2 and 3 clinical trials for its lyophilised mRNA vaccine for injection from the subject expert committee advising the Central Drugs Standards Control Organisation, reports Sohini Das. 

Gennova Biopharmaceuticals’ Covid-19 vaccine HGCO19, based on the mRNA technology platform, will be a lyophilised vaccine or one that is based on freeze-drying. This should help store the vaccine at much higher temperatures than the stringent sub-zero temperatures required to maintain a stable cold chain for other mRNA vaccines globally.

The lyophilised vaccine will come in a powder form and it will be mixed with diluents before administration.

In fact, Pfizer and BioNTech have already started a phase-3 study to evaluate the lyophilised (freeze-dried) formulation of the Pfizer-BioNTech vaccine, Pfizer noted on its website.

Gennova has got permission for the phase-2 and 3 clinical trials for its lyophilised mRNA vaccine for injection -- HGCO19 -- from the subject expert committee advising the Central Drugs Standards Control Organisation (CDSCO), according to the minutes of the meeting held on August 22.

Meanwhile, its peer Pfizer expects results from the phase-3 trials using a lyophilized vaccine later this year. “Results are anticipated in the second half of 2021. Subject to technical success, we will seek regulatory authorisation or approval,” the company said on its website.

Lyophilisation or freeze-drying is a complex process that is often used to stabilise vaccines. During the process, solvent is removed from the liquid product in manufacturing steps which include freezing, primary drying, and then secondary drying.

“The lyophilised formulation is a single-dose product prepared by filling vaccine solution into a vial, then lyophilizing or freeze-drying the contents of the vial to a powder. The vaccine is more stable in a powder form than liquid, and the lyophilized formulation is designed to be able to be shipped and stored at 2-8 degree Celsius. Prior to vaccination, the powder is reconstituted by dissolving with diluents,” Pfizer has said on its website

Gennova’s mRNA vaccine has an edge over other Covid-19 vaccines on the same platform as it remains stable at 2-8 degree Celsius. India’s nationwide immunisation infrastructure is well-equipped to handle temperature integrity of 2-8 degree Celsius across the cold chain.

"In a country like ours it is not viable to have vaccines that would require stringent temperature requirements of -70 degree Celsius or -20 degree Celsius to remain stable. This will make it virtually impossible to penetrate the hinterland," said someone close to the development.

mRNA vaccines typically have stringent temperature requirements to remain stable; the Pfizer-BioNTech vaccine needs -70 degree Celsius, while Moderna vaccine can remain stable for six months at -20 degree Celsius.

Suman Chakraborty, Dean, Sponsored Research and Industrial Consultancy and Innovator of the Rapid Diagnostic Technology COVIRAP, IIT Kharagpur, explained, “The mRNA-based vaccines are new technology platforms....The key to this technology is that it is much faster than conventional vaccines. The challenge is that it requires stringent temperature requirements to remain stable as the mRNA can be easily destroyed. There are numerous enzymes that will break these apart."

However, Chakraborty adds that by modifying the building blocks of the mRNA (neucleotides) -- a sort of genetic modification -- one can come up with modified versions that are more stable in a wider temperature range. "There are well-known technologies like lipid coating etc that can help to do this stabilisation. The crucial bit is that for a specific pathogen, this recipe has to be standardised. Once this is standardised, the enzymes will break down the mRNA, but this would happen slowly," he explains.

Gennova has associated mRNA with something called lipid inorganic nanoparticle (LION) that acts as the mRNA vaccine delivery system, which stabilises the mRNA and also acts as adjuvant till delivery into the patients.

Vaccines typically use adjuvants to improve the immune response. The adjuvants are pharmacological or immunological agents that improve the immune response of a vaccine.

This is interesting as there are not many examples globally of lyophilized vaccines which use adjuvants.