New treatment improves visual acuity score of patients with retinitis pigmentosa

Neurotech SA announced positive results from an open-label Phase I clinical trial (03-EI-0234) of its lead product, NT-501. NT-501 uses Neurotech’s patented Encapsulated Cell Technology (ECT) as a device to deliver ciliary neurotrophic factor (CNTF) to eyes of visually impaired patients with retinitis pigmentosa (RP). Neurotech is a biotechnology company specializing in the development of novel therapeutics to treat diseases of the eye. The company is headquartered in Paris.

Results of the latest clinical trial confirm that CNTF can be safely delivered into the vitreous of patients with RP and that the ECT device was well tolerated by all patients. Futhermore, some patients experienced more than one-line of improvement in their visual acuity score. These Phase I results were presented at the ARVO annual meeting and the trial was conducted at the National Eye Institute (NEI), Bethesda, USA. Neurotech has confirmed that it will now progress to a multi-center Phase II trial.

ECT, a technique developed and patented by Neurotech, allows for genetically-engineered specific protein delivery without manipulating the patient’s genetic information or transferring new genetic information into the target tissue. The Phase I study of NT-501 involved 10 patients with late-stage RP. The study was designed as an open-label safety and tolerability evaluation. Two doses of CNTF (5-fold difference in dose) were evaluated. Phase Ia treated 5 patients with a lower dose; Phase Ib treated 5 patients with a higher dose. The ECT device was implanted in one eye per patient and removed after six months. All explanted devices contained viable cells that continued to produce CNTF.

Commenting on the positive results, Weng Tao, MD, PhD, CSO and VP of R&D with Neurotech said: “These safety and tolerability results are extremely encouraging and strengthen our confidence in pursuing NT-501 for treating RP and other retinal degenerative diseases. I would like to thank the National Eye Institute for conducting this milestone study and for its continued involvement with this technology.”

Al Reaves, PhD, VP of Clinical Development with Neurotech confirmed: “This study represents the first use of ECT in human eyes and it is reassuring that the devices were safe and well-tolerated. We are planning Phase II development with well-designed and controlled multi-center clinical studies to help understand the role that NT-501 will play in treating patients with retinitis pigmentosa and other retinal degenerative conditions.”

In this trial, the small ECT device was surgically-implanted into the vitreous cavity through the pars plana in one eye per patient. The primary inclusion criteria for the study eye included visual acuity of 20/100 or worse, central visual field diameter of 40 degrees or less, and flicker ERG amplitude of 2 µV or less. The first 2 patients were also required to have visual acuity of 20/400 or worse. After surgical implantation of the device, each patient was followed for six months after which the device was explanted. Safety and tolerability was monitored by an independent Data and Safety Monitoring Committee. All 10 patients completed the study as planned and the devices have been explanted. The ECT devices were well tolerated during the 6 months of implantation and the surgical procedure resulted in minimal or no observed inflammatory reaction. No serious adverse events were reported and in the untreated fellow-eye, there was little change from baseline in the visual acuity score during follow-up. In the treated study-eye, however, the visual acuity score was more variable during follow-up: while some treated eyes showed little change from baseline, some patients experienced more than one-line of improvement in their visual acuity score.

In addition to NT-501 for the treatment of Retinitis Pigmentosa, Neurotech is applying ECT technology to deliver other protein factors for the treatment of other ophthalmic diseases, including anti-angiogenic factors for the treatment of the wet form of age-related macular degeneration (AMD) and diabetic macular edema (DME), and anti-inflammatory factors for the treatment of posterior uveitis.