for people ages 7 years and up (full criteria)
at San Francisco, California and other locations
study started
estimated completion



The objective of the study is to gain a better understanding of disease progression over time in participants with X-linked retinitis pigmentosa (XLRP).


This study was previously posted by NightstaRx Ltd. In October, 2020, sponsorship of the trial was transferred to Biogen.


X-Linked Retinitis Pigmentosa RP GTPase regulator (RPGR) Degenerative retinal disease XLRP Natural history Rare disease Retinitis Retinitis Pigmentosa Other: Assessments Subgroup 1 Subgroup 2


You can join if…

Open to people ages 7 years and up

  1. Have documentation of a pathogenic mutation in the retinitis pigmentosa GTPase regulator (RPGR) gene.
  2. Are willing and able to undergo ophthalmic examinations, as required by protocol, for up to 24 months
  3. Have an ETDRS BCVA in at least 1 eye of ≥34 letters (Equivalent to Snellen ≥ 6/60 or 20/200; decimal 0.1; LogMAR 1.0).
  4. Mean retinal sensitivity in the eligible eye as assessed by microperimetry:
  5. Males with a mean retinal sensitivity of 68 loci ranging from ≥0.1 decibels (dB) and ≤20 dB.
  6. Females with a mean retinal sensitivity of 68 loci ranging from ≥0.1 dB and ≤25 dB.
  7. If female, have symptomatic disease with impairment of visual function.

You CAN'T join if...

  1. Have a history of amblyopia in the eligible eye.
  2. Have any other significant ocular or non-ocular disease/disorder which, in the opinion of the investigator, may put the participant at risk because of participation in the study, may influence the results of the study, may influence the participant's ability to perform study diagnostic tests, or impact the participant's ability to participate in the study. This includes clinically significant cataracts.
  3. Have participated in another research study involving an investigational medicinal product in the past 12 weeks or received a gene/cell-based therapy at any time previously (including but not limited to Intelligent Implant System implantation, ciliary neurotrophic factor therapy, nerve growth factor therapy).

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply


  • Research Site accepting new patients
    San Francisco California 94143 United States
  • Research Site accepting new patients
    Los Angeles California 90095-7000 United States


accepting new patients
Start Date
Completion Date
NightstaRx Ltd, a Biogen Company
Study Type
Last Updated