Live cells producing ciliary neurotrophic factor (CNTF) housed in a polymer implant had a beneficial effect in patients with macular telangiectasia type 2, according to a press release from Neurotech Pharmaceuticals.
Designed to last for 18 months, the encapsulated cell therapy (ECT) implant contains proprietary human retinal pigment epithelial cells that are genetically modified to secrete therapeutic doses of CNTF. The ECT is inserted into the vitreous through a single incision and sutured in place in a 20-minute outpatient surgical procedure. There, the cells continuously produce the therapeutic protein, which then diffuses out of the implant at the target site.
The phase 2 trial, which took place at 11 sites in the US and Australia, included 67 subjects who were randomized to receive either the implant (NT-501) or sham.
At 24 months, there was significantly less photoreceptor loss in eyes with NT-501. The area of ellipsoid zone break increased by 0.213 mm2 in sham eyes, significantly higher than that of treated eyes (0.148 mm2, P=0.030). Additionally, NT-501-treated eyes had significantly increased macular thickness than the control group (P=0.007). Secondary clinical outcomes showed reading speed was maintained in the study eyes while deteriorating in sham eyes (P=0.016).
“NT-501 appears to slow the rate of progression of the disease, and if additional studies replicate the phase 2 data, this therapy has the potential to become the first treatment available for [macular telangiectasia],” said Martin Friedlander, MD, PhD, president of the Lowy Medical Research Institute.
Consistent with previous studies of NT-501 in retinitis pigmentosa and dry AMD, the implant was well tolerated. No participants had the implant removed during the course of the study, and the majority of adverse events were related to the surgical procedure and resolved within 3 months.
Neurotech plans to initiate a phase 3 program by the end of 2017.