e14570 Background: Oral mucositis (OM) is a painful and dose-limiting toxicity of cancer chemotherapy and irradiation, characterized by breakdown of the oral mucosa. Trefoil factors (TFFs) are involved in protecting and healing mucosal tissue, and might thus represent a pharmacological tool for treatment of OM. Local delivery of recombinant TFFs at the oral mucosa by living, genetically modified Lactococcus (L.) lactis bacteria (ActoBiotics) seems a promising, safe and cost-effective clinical approach for the prevention and attenuation of oral mucositis. Methods: An environmentally contained Lactococcus lactis strain (AG013), engineered to express human (h)TFF1, was formulated for topical administration in the form of a mouth rinse. Efficacy of AG013 was assessed in a clinically relevant hamster model of acute, radiation-induced OM. The dosing regimen was 1.3 x 109 CFU/dose, once (qd) or three rinses (tid) daily, from day 0 (=day of radiation) to day 18. OM was scored from day 6 to day 28 using the WHO grading scale, and compared to the score of placebo-treated hamsters. The viability and survival of live L. lactis and the pharmacokinetics of the hTFF1 secreted were studied in healthy and OM hamsters. Results: Topical application of AG013 to the oral mucosa significantly reduced the severity and course of radiation-induced OM. In the AG013-treated groups, the number of animals days with ulcerative mucositis (grade 3 or higher) was significantly reduced to 27.5% and 30.8% (qd and tid respectively; P < 0.001), compared to 45.8 % in the placebo-treated group. Based on the observed survival and weight changes, AG013 appeared to be well-tolerated. Pharmacokinetic studies demonstrated that both living L. lactis and the hTFF1 secreted could be recovered from the administration site, for maximum 24 hours post-dosing, without systemic exposure. Conclusions: Oral administration of AG013 is safe and effective in reducing the severity and the course of OM in the hamster model, and therefore supports proof-of-concept for a mouth rinse formulation of AG013 to treat OM patients. [Table: see text]
Radioprotective effect of mefenamic acid against radiation-induced genotoxicity in human lymphocytes
