Muscle electrotransfer of Plasmid AMEP, a gene product for melanoma treatment, is safe and well tolerated in mice

Plasmid AMEP is a medicinal gene product encoding AMEP (Antiangiogenic Metargidin Peptide), the disintegrin domain of human metargidin, which inhibits melanoma tumour growth and angiogenesis in melanoma mice models. In order to evaluate its safety, preclinical regulatory safety studies have been conducted on Swiss CD-1 immunocompetent mice after single or repeated (four at 7-day interval) muscle administration(s) of plasmid AMEP followed by electrotransfer. First, the single high-dose (400 mu g) toxicity study showed that plasmid AMEP was safe and well tolerated as no significant modification was observed on haematology, blood biochemistry, tissue pathology compared to the control group. Microscopic examination of injected muscles showed moderate signs of inflammation and muscle fibers regeneration. Four Repeated administrations at 7-day interval of increasing doses of plasmid AMEP (25,100 or 400 mu g) showed a dose-related decrease in white blood cells count at 100 and 400 mu g at day 29, which was not observed at the end of the recovery period (day 50), suggesting reversibility. No Plasmid AMEP related organ pathology was noted, excepted for the injected muscles, which demonstrated an increase in inflammation and regeneration at the highest dose-level. No other relevant findings were observed in ophthalmology (fundus) and in blood vessel density of organs after CD-31 immunostaining. The No Observable Adverse Effect Level was established at 25 mu g/injection administered in mice once a week for 4 weeks. In conclusion, Plasmid AMEP did not showed major adverse effects after four muscle administrations and did not seem to alter normal physiologic angiogenesis.