Rare Disease Report

First Patient Dosed in X-Linked Retinitis Pigmentosa (XLRP) Treatment

APRIL 18, 2018
Krista Rossi
Today, Applied Genetic Technologies Corporation announced that the first patient was dosed in its Phase 1/2 clinical trial evaluating the safety and efficacy of AGTC-501 for the treatment of X-linked retinitis pigmentosa (XLRP).

The investigational adeno-associated virus (AAV-based) gene therapy, (rAAV2tYF-GRK1-RPGR), is a novel recombinant AAV vector expressing a human RPGR gene (rAAV2tYF-GRK1-RPGR) in patients with XLRP.   

XLRP is an inherited condition that affects young boys and men. It causes the development of night blindness and eventually leads to legal blindness by patients’ early forties.

Sue Washer, president and CEO of AGTC, explained the significance of the first patient dosed with the treatment. “Dosing the first patient in our Phase 1/2 clinical study is an important step forward in advancing a new gene therapy in individuals with XLRP, a condition with no approved treatment options.”1

Dr David Birch of Retina Foundation of the Southwest is following the first dosed patient, and Dr Andreas Lauer of Oregon Health & Science University performed the surgery.

The Phase 1/2 trial is an open-label, dose escalation study to assess the safety and efficacy of subretinal administration of AGTC-501. The study aims to enroll 15 participants with XLRP and sequentially enroll them in 4 groups. Respectively, low, middle, and high doses of the investigational study agent will be administered to individuals in Groups 1, 2, and 3. The maximum tolerated dose, which will be established by the first 3 groups, will be administered to Group 4.

Primary outcome measures will include the number of participants who experience adverse events and abnormal clinically relevant hematology/clinical chemistry parameters.
All primary and secondary measures will be measured from Day 0 to Month 36. Secondary outcome measures will include changes from the baseline in visual function by perimetry, visual acuity by Early Treatment Diabetic Retinopathy Study (ETDRS), retinal structure by ocular coherence tomography (OCT), and VFQ-25 quality of life questionnaires. Overall efficacy will be measured by the evaluation of changes in retinal structure, function, and quality of life.2

Stephen Rose, PhD, chief scientific officer for the Foundation Fighting Blindness (FFB), expressed his excitement regarding the first KLRP patient dosed in the Phase 1/2 clinical trial. “This is an exciting clinical milestone for one of the first potential treatments of XLRP. The Foundation’s registry, My Retina Tracker, which is supported in part by a grant from AGTC, continues to provide invaluable support in identifying patients with XLRP, and other inherited retinal diseases. It allows us to inform them of clinical trials, such as this gene therapy in XLRP, that have the potential to transform their lives.”

The estimated primary completion date for the Phase 1/2 clinical trial is January 2022.

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References:
  1. AGTC Doses First Patient in Phase 1/2 Clinical Study of Gene Therapy for the Treatment of X-Linked Retinitis Pigmentosa. http://globenewswire.com/news-release/2018/04/18/1480721/0/en/AGTC-Doses-First-Patient-in-Phase-1-2-Clinical-Study-of-Gene-Therapy-for-the-Treatment-of-X-Linked-Retinitis-Pigmentosa.html?ev=1. Accessed April 18, 2018.
  2. Safety and Efficacy of rAAV2tYF-GRK1-RPGR in Subjects With X-linked Retinitis Pigmentosa Caused by RPGR-ORF15 Mutations. https://clinicaltrials.gov/ct2/show/record/NCT03316560?term=rAAV2tYF-GRK1-RPGR&cond=XLRP&rank=1. Accessed April 18, 2018.


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