New Treatment Improves Visual Acuity Score of Patients with Retinitis Pigmentosa

Main Category: Eye Health / Blindness
Article Date: 05 May 2005 - 9:00 PDT


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.

1. About Retinitis Pigmentosa (RP)

RP is a group of inherited retinal diseases that affects about 100,000 Americans and 1.5 million people worldwide. It causes the progressive deterioration of specialized, light-absorbing cells in the retina, the paper-thin tissue that lines the back of the eye like film in a camera. As these cells slowly degenerate, people with RP develop night blindness and a gradual loss of peripheral vision. By about age 40, most have tunnel vision, although many may retain good central vision. Between the ages of 50 and 80, however, they typically lose their remaining sight. The extent of vision loss in people of the same age with RP may be different.

2. About Encapsulated Cell Technology (ECT)

ECT is a unique technology to overcome drug delivery problems into the back of the eye. ECT enables the controlled, continuous, long-term delivery of therapeutic proteins directly to the retina. In addition, the implants can be retrieved, providing an added level of safety as well as the ability to reverse or adjust therapy, if needed. ECT relies on the use of an immunoisolatory hollow fiber membrane technology to allow the implantation of genetically engineered cells that continuously produce the therapeutic protein at the site of implantation. The cells are loaded into the interior volume of the hollow fiber membrane and attach to a proprietary supportive matrix within this space. The genetically modified cells remain captive within the ECT device thus avoiding the risks associated with traditional gene therapy. Long term protein delivery (18 months) in the vitreous cavity of the eye has consistently been achieved when ECT devices containing human retinal pigmented epithelial (RPE) cells genetically engineered to secrete CNTF have been implanted in a highly disparate mammalian species (rabbits).

3. About Neurotech

Neurotech is a biotechnology company specializing in the development of novel therapeutics to treat diseases of the eye. The company's initial focus is on chronic diseases affecting the back of the eye, especially the retina, because retinal diseases represent the greatest unmet medical need and therefore offer the largest market opportunities in ophthalmology. The Company has one product (NT-501) in development for the treatment of retinitis pigmentosa and other degenerative diseases of the retina, and is evaluating other neurotrophic factors and agents that can be used with ECT for treating other retinal diseases. The company is headquartered in Paris with an American subsidiary, Neurotech USA, Inc., located in Lincoln, RI, south of Boston. Neurotech is supported in its scientific and business strategies by world experts in ophthalmology and by a group of international investors led by Apax Partners and Merlin Biosciences.

Reference URL
http://www.neurotech.fr

http://www.alphagalileo.org

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