Percutaneous Intratumoral Immunoadjuvant Gel Increases the Abscopal Effect of Cryoablation for Checkpoint Inhibitor Resistant Cancer

• Published in: Advanced healthcare materials Vol. 13; no. 6; pp. e2301848 - n/a
• Main Authors: Som, Avik, Rosenboom, Jan‐Georg, Wehrenberg‐Klee, Eric, Chandler, Alana, Ndakwah, Gabrielle, Chen, Eric, Suggs, Jack, Morimoto, Joshua, Kim, Jonathan, Mustafa, Abdul Rehman, Marcos‐Vidal, Asier, Fintelmann, Florian J., Basu, Arijit, Langer, Robert, Traverso, Giovanni, Mahmood, Umar
• Format: Journal Article
• Language: English
• Published: Germany 01.03.2024
• Subjects: cancer immunotherapy; drug delivery; image guided therapy; imiquimod; intratumoral immunoadjuvants; drug delivery; image guided therapy; cancer immunotherapy; imiquimod; intratumoral immunoadjuvants
• ISSN: 2192-2640; 2192-2659
• DOI: 10.1002/adhm.202301848

Percutaneous cryoablation is a common clinical therapy for metastatic and primary cancer. There are rare clinical reports of cryoablation inducing regression of distant metastases, known as the “abscopal” effect. Intratumoral immunoadjuvants may be able to augment the abscopal rate of cryoablation, but existing intratumoral therapies suffer from the need for frequent injections and inability to confirm target delivery, leading to poor clinical trial outcomes. To address these shortcomings, an injectable thermoresponsive gel‐based controlled release formulation is developed for the FDA‐approved Toll‐like‐receptor 7 (TLR7) agonist imiquimod (“Imigel”) that forms a tumor‐resident depot upon injection and contains a contrast agent for visualization under computed tomography (CT). The poly‐lactic‐co‐glycolic acid‐polyethylene glycol‐poly‐lactic‐co‐glycolic acid (PLGA‐PEG‐PLGA)‐based amphiphilic copolymer gel's underlying micellar nature enables high drug concentration and a logarithmic release profile that is additive with the neo‐antigen release from cryoablation, requiring only a single injection. Rheological testing demonstrated the thermoresponsive increase in viscosity at body temperature and radio‐opacity via microCT. Its ability to significantly augment the abscopal rate of cryoablation is demonstrated in otherwise immunotherapy resistant metastatic tumors in two aggressive colorectal and breast cancer dual tumor models with an all or nothing response, responders generally demonstrating complete regression of bilateral tumors in 90‐day survival studies. Image‐guided intratumoral imigel ± cryoablation can overcome immunotherapy resistance to induce complete regression in distant tumor metastases. By optimizing this platform for interventional radiologists, who currently do most deep percutaneous intratumoral injections and cryoablation therapies, the technology reduces the hurdles for translating personalized cancer vaccines.