Oral Hydroxychloroquine (HCQ) for Retinitis Pigmentosa Caused by P23H- Rhodopsin (RHO)

  • End date
    Oct 21, 2023
  • participants needed
  • sponsor
    University of Michigan
Updated on 21 March 2022
corrected visual acuity
genetic testing
pupil dilation
genetic analysis
retinal degeneration


This research study is being done to learn what effect 12 months of treatment with oral hydroxychloroquine (HCQ) will have on the retina in people with retinitis pigmentosa (RP). The hypothesis is that treatment with HCQ is safe and tolerable in patients with autosomal dominant retinitis pigmentosa (adRP) caused by P23H-RHO, and may arrest progression of retinal degeneration by altering the autophagy pathway in photoreceptors.

Participants that meet eligibility and agree to the study will be asked to take the study medication (HCQ) for 12 months and have evaluations for up to approximately 18 months from the baseline visit. There will be a total of 6 visits (1 is a phone visit) and will include general examinations, blood work, electrocardiograms, along with special testing of the retina.

Condition Retinitis Pigmentosa
Treatment Hydroxychloroquine lower dose, Hydroxychloroquine higher dose
Clinical Study IdentifierNCT04120883
SponsorUniversity of Michigan
Last Modified on21 March 2022


Yes No Not Sure

Inclusion Criteria

Stated willingness to comply with all study procedures and availability for the duration of the study
Signed and dated informed consent form
Early Treatment Diabetic Retinopathy Study Best Corrected Visual Acuity (ETDRS BCVA) of 20 letters (approximately 20/400 Snellen) or better in at least one eye
Clinical diagnosis of autosomal dominant retinitis pigmentosa
Confirmed to have one copy of the P23H-RHO pathogenic variant by genetic testing at a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory
Clarity of ocular media and adequate pupillary dilation to allow for adequate clinical ocular examination and retinal imaging
Ability to perform testing required by the study as determined by the investigator
Ability to take oral medication (medication tablets must be swallowed whole) and be willing to adhere to the daily medication regimen
For females of reproductive potential: use of highly effective contraception beginning no later than 1 week after the first screening visit, and agreement to use such a method during study participation and through the end of the washout period (6 months after the end of HCQ administration)
Agreement to adhere to Lifestyle Considerations throughout study duration (take the study drug with meals, avoid taking over-the-counter antacids or kaolin-containing products 4 hours before or after taking the study drug)

Exclusion Criteria

Use of any other drugs which are known to prolong the QT interval
Concurrent use of any of the following drugs, if the drug cannot be discontinued or substituted: digoxin, antiepileptic medications, cimetidine, methotrexate, cyclosporine, praziquantel, ampicillin
Current or previous use of tamoxifen
Pregnancy or lactation
Known allergy or hypersensitivity to hydroxychloroquine or any other 4-aminoquinoline drugs (chloroquine, amodiaquine, mefloquine, quinacrine, etc.), or known history of glucose-6-phosphate dehydrogenase deficiency
Treatment with another investigational medical intervention for retinitis pigmentosa within 3 months, or any ever previous treatment with an investigational surgical intervention
Any pre-existing cardiac, renal, hepatic, or hematologic disease, any prior history of psoriasis or porphyria, or any alcoholism
Abnormal screening laboratory values including aspartate transaminase (AST) or alanine transaminase (ALT) > 2.0 x upper limit of normal, subnormal glomerular filtration rate (< 90 mL/min/1.73m2) or abnormal complete blood count attributable to underlying hematologic disease such as malignancy, aplastic anemia, agranulocytosis, leukopenia, or thrombocytopenia
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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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