A Phase 4 interventional study of NT-501/revakinagene taroretcel-lwey in Macular Telangiectasia Type 2 (MacTel), sponsored by Neurotech Pharmaceuticals. Recruiting at 26 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-25.
Sponsored by Neurotech Pharmaceuticals · Phase 4, Interventional, and Treatment
The purpose of this global, multicenter, open-label, Phase 4 clinical extension study is to evaluate the long-term safety and efficacy of revakinagene taroretcel-lwey (Encelto™; hereinafter referred to as NT-501), in participants with macular telangiectasia type 2 (MacTel) who previously received the intraocular implant in a Phase 1, Phase 2, or Phase 3 clinical study and have retained at least 1 NT-501 at study entry. In addition, this study will evaluate the safety and efficacy of NT501 in participants who previously underwent the sham procedure in a Phase 3 MacTel clinical study and elect to have NT-501 implanted intraocularly in this Phase 4 study.
This extension study consists of 3 arms:
Arms 1 and 2 are noninterventional and observational studies. For participants who previously received a single NT-501 implant, the implanted eye is designated the study eye. For participants who received an NT-501 in both eyes (ie, the first implant received in NTMT-01, NTMT-02, NTMT-01/02E, NTMT-03A, or NTMT-03B, and the second implant received in NTMT-02B), both eyes will be designated as study eyes.
Only participants in Arm 3 will receive active intervention during this Phase 4 study. A participant can receive NT-501 in either eye that meets eligibility criteria according to investigator assessment, and in accordance with participant choice. However, if only 1 eye is eligible for implantation based on all inclusion/exclusion criteria, then that eye will be selected for NT-501 implantation. The eye selected for NT-501 implantation will be designated as the study eye.
Regardless of study eye designation, both eyes of each participant in all 3 study arms will be evaluated during the study.
69 studies on the registry are indexed under Telangiectasis; 12 are open to participants now.
This study's planned enrollment of 234 is above the median of 30 across 59 interventional studies indexed under Telangiectasis.
Browse Telangiectasis studies →Neurotech Pharmaceuticals is the lead sponsor of 13 studies on the registry; 2 are open to participants now.
Of its 8 completed or terminated interventional studies of FDA-regulated products, 7 (88%) have results posted.
Counted across the registry records on this site, refreshed daily.
Inclusion Criteria
To be eligible to participate in this study, an individual participant must meet all the following criteria:
Male or female adult participants who previously completed an NT-501 MacTel clinical study and:
Arm 2: received NT-501 intraocular implant in the Phase 1 study (NTMT-01), Phase 2 study (NTMT-02), or in the substudy of the Phase 1 and Phase 2 extension study (NTMT-01/02E) and have retained at least 1 NT-501 at study entry.
Note: participants who received NT-501 in both eyes (ie, participated in study NTMT-02B) will be enrolled in either Arm 1 or Arm 2 based on the study in which the first NT 501 was implanted (ie, participants who received the first implant in a Phase 3 study will be enrolled in Arm 1 and those who received the first implant in the Phase 1 study or Phase 2 study will be enrolled in Arm 2).
Exclusion Criteria
To participate in this study, the potential participant must not meet any of the following criteria. (Note that the ocular exclusion criteria are relevant to the study eye[s], unless indicated for both eyes):
Exclusion Criteria Applicable to Arms 1, 2, and 3:
Participant received Encelto commercial implant in the fellow eye, if applicable, less than 3 months prior to study screening.
Exclusion Criteria Applicable to Arm 3 Only:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
For participants who received NT-501 (ENCELTO) in a previous Phase 3 study (NTMT-03-A or NTMT-03-B), or for participants who received NT-501 (ENCELTO) in both eyes (i.e. participated in study NTMT-02B) but received the first NT-501 (ENCELTO) implant in a Phase 3 study. No new treatment intervention will be administered. Arm 1 is focused on long term follow-up for participant who already has the ENCELTO implant at time of study screening and enrollment.
Combination Product: NT-501/revakinagene taroretcel-lwey
For participants who received NT-501 (ENCELTO) in a previous Phase 1 study (NTMT-01), Phase 2 study (NTMT-02), in the sub study of Phase 1 and Phase 2 extension study (NTMT-01/02E), or for participants who received NT-501 (ENCELTO) in both eyes (i.e. participated in study NTMT-02B) but received the first NT-501 (ENCELTO) implant in a Phase 1 or Phase 2 study. No new treatment intervention will be administered. Arm 2 is focused on long term follow-up for participant who already has the ENCELTO implant at time of study screening and enrollment.
Combination Product: NT-501/revakinagene taroretcel-lwey
For participants who underwent Sham procedure in either Phase 3 study (NTMT-03-A or NTMT-03-B) and will receive NT-501 in this study.
Combination Product: NT-501/revakinagene taroretcel-lwey
Drug page: Ciliary Neurotrophic Factor
NT-501 is surgically implanted into the vitreous cavity to continuously release recombinant human ciliary neurotrophic factor (CNTF).
Also known as: ENCELTO
Incidence of ocular and nonocular adverse events (AEs) and serious adverse events (SAEs)
Incidence of ocular and nonocular adverse events (AEs) and serious adverse events (SAEs)
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Percentage of participants with a loss of 15 letters or more in best corrected visual acuity (BCVA) compared to presurgery baseline BCVA
Percentage of participants with a loss of 15 letters or more in best corrected visual acuity (BCVA) compared to presurgery baseline BCVA using the Early Treatment Diabetic Retinopathy Study (ETDRS) distance chart
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Change from presurgery baseline in ellipsoid zone (EZ) area loss
Change from presurgery baseline in ellipsoid zone (EZ) area loss as measured by en face spectral domain optical coherence tomography (SD-OCT) for both eyes
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Change from presurgery baseline in BCVA
Change from presurgery baseline in BCVA using the ETDRS distance chart for both eyes
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Change from presurgery baseline in aggregate retinal sensitivity
Change from presurgery baseline in aggregate retinal sensitivity as measured by microperimetry within the EZ line break area for both eyes
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Change from presurgery baseline in monocular reading speed
Change from presurgery baseline in monocular reading speed for both eyes
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Change from presurgery baseline in the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25)
Change from presurgery baseline in NEI-VFQ-25 near activities subscale score. All items are scored so that a high score represents better functioning. Each item is then converted to a 0 to 100 scale so that the lowest and highest possible scores are set at 0 and 100 points, respectively.
Time frame: Baseline and annually for up to 5 yrs for Arms 1 and 2 and baseline, perioperative, and annually for up to 5 yrs for Arm 3 participants
Plan to share: No
No publications or documents are linked to this record.
Started Nov 2025 (actual). Primary completion is estimated for Jan 2032, 73 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Ciliary Neurotrophic Factor
Neurotech Pharmaceuticals