Thermosensitive hydrogels as sustained drug delivery system for CTLA-4 checkpoint blocking antibodies

Chih Kit Chung, Marieke F. Fransen, Koen van der Maaden, Yaima Campos, Jomarien García-Couce, Dana Kralisch, Alan Chan, Ferry Ossendorp, Luis J. Cruz*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Thermosensitive poloxamer 407 (P407) hydrogels were evaluated as slow release system for optimizing CTLA-4 therapy. Slow release reduces systemic antibody levels and potentially mitigates the side effects of CTLA-4 therapy. The 25% P407 hydrogel is injectable at room temperature and depots are established quickly after subcutaneous injection. Scanning electron microscopy revealed the porous structure of the hydrogel, average pore surface was 1335 μm2. Release studies were optimized using the human IgG antibody. IgG was easily incorporated in the hydrogel by simple mixing and no antibodies were lost during preparation. In vitro, hydrogels showed low burst release within the first 24 h. Total IgG load was gradually released within 120 h. In vitro cytotoxicity assays showed that P407 is not cytotoxic and induces no immune activation by itself. In vivo, P407 hydrogels significantly reduced serum IgG levels, were biocompatible and were broken down 1 week after injection. Finally, local hydrogel delivery of anti-CTLA-4 antibodies near established tumors effectively slowed down tumor growth, whilst significantly reduced serum anti-CTLA-4 levels. Altogether, P407 hydrogels represent promising delivery systems for the optimization of CTLA-4 blocking therapy.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalJournal of Controlled Release
Publication statusPublished - 10 Jul 2020

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