Developers of the first wave of COVID-19 prophylactics used a range of vaccine technologies but all relied on the same, tried-and-tested vial and syringe administration system. Now, with the pandemic in a new phase, Sorrento Therapeutics has presented preclinical data suggesting delivery to lymph nodes can slash the dose required to generate immunity.
Intramuscular injections are quick, familiar to healthcare workers and use widely available delivery technology, making them ideal for the first phase of the pandemic. Sorrento, though, sees potential benefits to directing vaccines to the skin and draining lymph nodes because of the concentration of antigen-presenting cells.
To test the idea, Sorrento developed a mRNA vaccine in a lipid nanoparticle formulation, similar to the approach taken by Moderna and Pfizer-BioNTech, and compared the effects of administering it via intramuscular injections or a lymphatic delivery system.
The lymphatic delivery system uses microneedles to puncture the top layer of the skin and release a drug into the boundary between the epidermis and the dermis. The antibody responses seen in mice that received 10 μg of the vaccine via intramuscular injection were comparable to responses from 1 μg administered using the lymphatic delivery system, according to data shared in a preprint paper.
Based on the data, Sorrento plans to “move forward aggressively with IND-enabling studies.” The preclinical data point to the potential for the lymphatic delivery system to reduce the amount of a vaccine needed to provide immunity. Such dose sparing could enable more people to get protected, although, in many parts of the world, supply is no longer the barrier to higher vaccination rates.