PARIS ¿ Neurotech SA, a French biotechnology company developing cell-based therapies for diseases of the eye and the central nervous system, successfully completed a subretinal transplantation of human cell lines in a rat model of retinal degeneration.

The experiment was carried out in conjunction with the London Institute of Ophthalmology and the University of Sheffield in England and applied the animal model of the Royal College of Surgeons in London. The results were published in the Proceedings of the National Academy of Sciences.

The rats used in the trial were suffering from a genetic malfunction of retinal epithelial cells, causing a loss of vision. After undergoing the transplant of human cell lines genetically modified by Neurotech, the dystrophic rats showed an appreciable improvement in the protection of the photo-receptive cells of their retinas and conserved their visual function for five months, Neurotech CEO Tom Shepherd said.

Both functional and histological evaluation tests were performed to establish the efficacy of the transplant. Optokinetic behavioral tests conducted 10 weeks and 20 weeks after the transplant demonstrated that the dystrophic rats operated on were able to respond to visual stimuli. Electrophysical analyses also attested to the preservation of the visual functions of the treated rats. Furthermore, histological tests showed that key cells in operated rats¿ retinas were preserved, unlike animals that were not treated.

Shepherd told BioWorld International that the main advance of this therapy was the use of human cells in place of animal cells, pointing out that in the past the company had used pig xenotransplantation. In view of the added complications of using animal cells, however, ¿we have changed our focus totally onto human cell lines,¿ he said. Phase I trials of this therapy are scheduled to start in France next year, and Shepherd said he expects the results to be even more convincing in humans, with their visual function restored for more than the five months achieved with the rats.

Pointing out that the successful in vivo functioning of this transplant ¿validates the company¿s research and technology,¿ Shepherd said: ¿Today more than ever, Neurotech definitely is the biotechnology company of the eye.¿ Having demonstrated the ¿hidden potential of human retinal epithelial cells to treat retinal degeneration caused by a malfunction of these cells,¿ Neurotech plans to push ahead with preclinical and clinical development of therapies for retinal diseases, in general, and age-related macular degeneration, in particular.

All the therapies being developed by Neurotech, which is based in France¿s national biotechnology science and business park at Evry, use genetically modified cell lines derived from the eye and the CNS, either in encapsulated form as a means of delivering proteins to specific sites over long periods of time, or directly as a cell therapy for replacing damaged cells. Now that it has decided to halt development of animal cell-based products, Neurotech is replacing animal cells by human cell lines in other therapies it is developing, including one for glioblastoma that completed a Phase I trial.

Last May, Neurotech completed what it termed a ¿pre-IPO¿ funding round that netted it EUR35 million (US$30.5 million), already having raised US$3 million and US$14.5 million in two earlier funding rounds in April 1997 and November 1998.