Immunotherapy hydrogel tackles cancer with slow-release action

Researchers at Rice University have developed a slow-release hydrogel embedded with immunotherapy drugs, which targets cancer over an extended period.

HydrogelCredit:  Hartgerink Research Group

Known as STINGel (it activates the STimulator of INterferon Gene), the multi-domain peptide (MDP) gel releases a steady dose of treatment that triggers the immune system and helps fight cancerous cells. Immunotherapy is a well-established method of fighting cancer, but current techniques rely on multiple injections, as the drugs are quickly flushed from the body.

In contrast, the hydrogel is first injected as a liquid, which turns semi-solid in the body, then degrades over time. STINGel’s payload is immunotherapy drugs called cyclic dinucleotides (CDNs). According to Rice chemist and bioengineer Jeffrey Hartgerink, the concentration of CDN is key to attacking the cancer.

“The normal approach to CDN delivery is simple injection, but this leads to very rapid diffusion of the drug throughout the body and reduces its concentration at the site of the tumour to very low levels,” he said. “Using the same amount of CDN, the STINGel approach allows the concentration of CDN near the tumour to remain much higher for long periods of time.”

STINGel was tested in vivo on rats, alongside control groups with CDN alone, control collagens with CDN, and MDP with no CDN. Just one out of ten rats injected with CDN alone or via the collagen survived beyond 105 days. However, six of the ten rats treated with STINGel lasted past this point. What’s more, those rats also proved resistant to further implantation of cancer cells, meaning their immune systems were trained to successfully identify and destroy both the existing cancer and future occurrence of that cancer, according to Hartgerink.

“The CDN we used in this study is currently in clinical trials,” he said. “We think that our STINGel approach has the potential to significantly broaden the scope of this powerful immunotherapy drug to a larger range of resistant cancers.”

The study is published in the journal ScienceDirect.