Less than 6 months after receiving priority review for its Biological License Application (BLA) of NT-501 (revakinagene taroretcel), an encapsulated cell therapy (ECT) designed to treat macular telangiectasia type 2 (MacTel), Neurotech Pharmaceuticals, Inc. announced the FDA has extended its review period.
Let’s begin with Neurotech.
The private, Rhode Island-based clinical-stage biotechnology company is developing sustained drug deliveries for chronic retinal diseases—with a specific focus on MacTel.
- About MacTal: This rare, age-related neurodegenerative retinal disease causes gradual central vision deterioration in adults aged 40+. See how it develops.
The company’s core platform technology: The ECT platform.
Give me more on this platform.
The ECT is designed to “continuously produce and deliver targeted therapeutics”—singularly and in combination—to the back of the eye for long-term maintenance.
- Its foundation is the NTC-200 cell line, which not only operates under low oxygen and nutrient conditions but can also be genetically manipulated under strict selection methods.
Featured in the ECT is a small, semi-permeable capsule filled with proprietary allogeneic retinal epithelium cells (RPE) cells that are genetically modified to produce specific therapeutic proteins for targeted disease treatments.
And what process does the capsule undergo?
This capsule is inserted into a patient’s vitreous and sutured to the sclera during an outpatient procedure.
Once in place: The semipermeable membrane of the capsule enables critical nutrients to enter and therapeutic proteins to exit into the vitreous.
- And from there: The intended result is continuous and targeted treatment.
As a bonus during this process: The membrane provides protection to the encapsulated RPE cells from a patient’s immune system, enabling both functionality and long-term survival.
Sounds promising! So how does this candidate come into play?
NCT-501 is an ocular implant that utilizes the ECT platform to transport therapeutic doses of ciliary neurotrophic factor (CNTF) directly into the retina.
- Its intent: To slow disease progression.
Refresh: CNTF, a member of the interleukin-6 family of cytokines, is a neuroprotective protein (hormone) that supports the survival of neurons within various parts of the human body—including the brain and retina.
More specifically related to MacTel: CNTF has been shown to protect against photoreceptor loss in the retina.
Alrighty, now let’s talk about this original BLA submission.
As we mentioned, Neurotech was granted priority review by the FDA for its BLA on NT-501 back in June 2024.
The basis for this: Most recently, NT-501’s performance in two randomized phase 3 studies (Protocol A and B) among 200+ MacTel Type 2 patients.
Those details (in a nutshell):
- The primary endpoint: Rate of change in ellipsoid zone area loss from baseline to 24 months
- The findings: A statistical significance was demonstrated for the primary endpoint, with the implant determined to be safe, durable, and well-tolerated in both studies:
- 56.4% rate of reduction in Protocol A (p<0.0001)
- 29.2 % rate of reduction in Protocol B (p=0.021)
So, about this extension …
While the standard review period of a BLA is typically 6 months, the agency has extended its Prescription Drug User Fee Act (PDUFA) goal date by an additional 3 months:
- The original PDUFA date: Dec. 17, 2024
- The updated PDUFA date: March 18, 2025
And the reason for this?
Neurotech reported that these extra 90 days are needed for the FDA to “review additional data provided by the company in response to recent requests” from the agency.
Per the company, this was noted as “general data related to the requests.”