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Local injection of OK-432/fibrinogen gel into head and neck carcinomas
H Kumazawa1, T Yamashita, T Tachikawa
1Department of Otolaryngology, Kansai Medical University, Osaka, Japan.
Abstract:
Immunotherapy with biological response modifiers (BRM) is a possible strategy against head and neck solid tumours. However, the rapid disappearance of BRM from the tumour area is one of the reasons for its limited clinical application. In this pilot study, fibrinogen gel containing OK-432 (a compound composed of attenuated Streptococcus pyogenes), an inducer of natural killer cells and T-cell cytotoxity, was injected directly into head and neck solid tumours of 15 patients. A dose of 5 Klinische Einheiten (KE) of OK-432 was reconstituted in 1 ml aprotinin and mixed with fibrinogen, the latter to maintain the OK-432 locally. 3 patients showed tumour regression, and in addition, we observed histological changes in the injected tumour of all patients. These results suggest that OK-432/fibrinogen gel generates a local immune response, leading to tumour regression.
Insights
This pilot study explored OK-432/fibrinogen gel for head and neck tumors. Local injection of this biological response modifier (BRM) induced immune responses and tumor regression in some patients.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- Immunotherapy using biological response modifiers (BRM) shows promise for head and neck solid tumors.
- Limited clinical application of BRM is partly due to their rapid local clearance.
- Sustained local delivery of BRM is crucial for effective tumor immunotherapy.
Purpose of the Study:
- To evaluate the feasibility and preliminary efficacy of a novel OK-432/fibrinogen gel formulation for localized immunotherapy.
- To assess the local immune response and tumor regression following direct intratumoral injection of OK-432/fibrinogen gel.
- To investigate the potential of fibrinogen gel as a sustained-release vehicle for BRM in head and neck cancers.
Main Methods:
- A pilot study involving 15 patients with head and neck solid tumors.
- Direct intratumoral injection of OK-432 (attenuated Streptococcus pyogenes) encapsulated in fibrinogen gel.
- A dose of 5 Klinische Einheiten (KE) OK-432 was reconstituted with aprotinin and mixed with fibrinogen for local retention.
Main Results:
- Tumor regression was observed in 3 out of 15 patients.
- Histological changes indicative of an immune response were noted in all injected tumors.
- The OK-432/fibrinogen gel formulation facilitated local retention of the BRM.
Conclusions:
- OK-432/fibrinogen gel demonstrates potential as a localized immunotherapy for head and neck solid tumors.
- The formulation appears to induce a local immune response, contributing to tumor regression.
- Further clinical trials are warranted to confirm the efficacy and safety of this approach.