A Study Comparing Two Doses of AGTC-501 in Male Participants With X-linked Retinitis Pigmentosa Caused by RPGR Mutations (DAWN)

Beacon Therapeutics

Status and phase: Invitation-only; Phase 2

Conditions: X-Linked Retinitis Pigmentosa

Treatments: Biological: AGTC-501 (high dose and modified corticosteroid regimen); Biological: AGTC-501 (high dose and standard corticosteroid regimen); Biological: AGTC-501 (low dose and standard corticosteroid regimen)

Study type: Interventional

Funder types: Industry

Identifiers

NCT06275620

AGTC-RPGR-001 DAWN

Details and patient eligibility

About

This Phase 2 study is a non-randomized, open-label, study of the safety of AGTC-501 in participants with XLRP who have previously been treated with a full-length AAV vector-based gene therapy targeting RPGR protein.

Full description

This is a Phase 2, open-label, multicenter study to evaluate the safety of 2 doses of AGTC-501 administered as a single subretinal injection in participants with XLRP who have previously been treated with a full-length AAV vector-based gene therapy targeting RPGR protein.

The trial includes a screening period of up to 60 days and a 5 year study period.

Each participant will receive a single subretinal injection of one of two dose levels of AGTC-501 in their previously untreated eye. There will be 3 groups. Group 1 will receive the high dose and include up to 12 participants, Group 2 will receive the low dose and will include 6 participants, and Group 3 will include ~3-6 participants. Participants in Groups 1 and 2 will receive the standard corticosteroid regimen. A single subretinal injection of the high dose AGTC-501 will be administered to participants in Group 1 (n = 12), while participants in Group 2 (n = 6) will receive a single subretinal injection of low dose AGTC-501. Group 2 (low dose AGTC-501, Standard Steroid) will be dosed before moving to Group 3. After 6 Group 1 (high dose) study participants reach post-operative Month 1, all data will be reviewed by the DSMC. If no safety signals arise, additional participants, Group 3 (n ~ 3-6), will receive a single subretinal injection of the high dose with a modified course of corticosteroids.

Enrollment: 24 estimated patients

Sex: Male

Ages: 12+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Be ≥12 years of age
• Have one eye previously treated with an AAV vector-based gene therapy designed to provide full-length functioning RPGR protein.
• Have a BCVA no better than 78 letters and no worse than 34 letters
• Be able to perform all tests of visual and retinal function and structure in both eyes based on the participant's reliability and fixation, per the Investigator's discretion.
• Have detectable baseline mean macular sensitivity measured by MAIA microperimetry, as determined by the Investigator and confirmed by the Central Reading Center (CRC).
• Have detectable EZ line in the study eye as assessed by SD-OCT and confirmed by the CRC.

Exclusion criteria

• Have other known disease-causing mutations documented in the participant's medical history or identified through a retinal dystrophy gene panel that, in the opinion of the Investigator, would interfere with the potential therapeutic effect of the study agent or the quality of the assessments.
• Have pre-existing eye conditions that would preclude the planned surgery, interfere with the interpretation of study endpoints, or increase the risk of surgical complications
• Had intraocular surgery within 90 days of study treatment administration.
• Have any active ocular/intraocular infection or inflammation
• Have a history of steroid-induced raised IOP of >25 mmHg following corticosteroid exposure, despite topical IOP-lowering pharmacologic therapy.

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Sequential Assignment

Masking: None (Open label)

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24 participants in 3 patient groups

Group 1 (High Dose, Standard Corticosteroid)

Experimental group

Description:

Following a pars plana vitrectomy, the previously untreated eye of participants (n=up to 12) will receive a central subretinal injection at the high dose in the study eye at the Baseline visit; no treatment will be administered in the previously treated fellow eye. The corticosteroid taper for all treated participants in Groups 1 and 2 (high and low doses with standard corticosteroid regimen) will be a standard taper over the course of several weeks.

Treatment:

Biological: AGTC-501 (high dose and standard corticosteroid regimen)

Group 2 (Low Dose, Standard Corticosteroid)

Experimental group

Description:

Following a pars plana vitrectomy, the previously untreated eye of participants (n=6) will receive a central subretinal injection at the low dose in the study eye at the Baseline visit; no treatment will be administered in the previously treated fellow eye. The corticosteroid taper for all treated participants in Groups 1 and 2 (high and low doses with standard corticosteroid regimen) will be a standard taper over the course of several weeks.

Treatment:

Biological: AGTC-501 (low dose and standard corticosteroid regimen)

Group 3 (High Dose, Modified Corticosteroid)

Experimental group

Description:

Following a pars plana vitrectomy, the previously untreated eye of participants (n=approximately 3-6) will receive a central subretinal injection at the high dose in the study eye at the Baseline visit; no treatment will be administered in the previously treated fellow eye. Participants in Group 3 (high dose, modified corticosteroid) will have a more rapid corticosteroid taper.

Treatment:

Biological: AGTC-501 (high dose and modified corticosteroid regimen)