Developing safe and efficient bioformulations using approved materials and ingenious designs can accelerate the clinical translation process.

Scientists from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences have developed a new therapeutic tumour vaccine based on self-healing polylactic acid microcapsules, which can efficiently activate the immune system and inhibit tumour development.

This research was published in Science Advances. Therapeutic cancer vaccines that harness the immune system to reject cancer cells have shown great promise for tumour treatment. The research team, led by Prof. MA Guanghui and Prof. WEI Wei from IPE, already designed and fabricated a variety of tumour vaccines in their previous work.

Theses vaccines have been proven effective in different tumour models, such as lymphoma, melanoma and breast cancer. The researchers were impelled to improve the earlier tumour vaccines, however, due to certain limitations. For example, Prof. MA said that an unfavourable immunisation microenvironment, along with a complicated preparation process and the need for frequent vaccinations significantly compromised their performance. “Therefore, we designed a novel microcapsule-based formulation for high-performance cancer vaccinations,” said Prof. MA. This study represents the first time researchers used self-healing microcapsules with post-encapsulation, multiple loading, and efficient modulation of immunisation microenvironments in a tumour vaccine. The special self-healing feature provides a mild and efficient paradigm for antigen microencapsulation. After vaccination, these microcapsules create a favourable immunisation microenvironment in situ, wherein antigen release kinetics, recruited cell behaviour and acid surrounding environment work in a synergetic manner. Owing to synergetic effects, the vaccine succeeds in increasing antigen utilisation, improving antigen presentation and activating antigen presenting cells.

“As a result, effective T cell response, potent tumour inhibition, anti-metastatic effects and prevention of postsurgical recurrence are achieved with various types of antigens in different tumour models,” said Prof. WEI. Moreover, the researchers verified the availability of the novel vaccine platform used in the neoantigen vaccine, which conforms to precision medicine, said Prof. WEI. Due to the simple post-encapsulation process, the clinicians were able to prepare the neoantigen formulation by themselves at any time.

A peer reviewer from Science Advances described the study as “comprehensive and rationally designed.” The reviewer also emphasised that the results are “impressive” and the work has “high value for therapeutic vaccines and cancer immunotherapy.