PQ-504a-001 (Fuchs Focus) is an open-label, intra-subject-controlled study in subjects with FECD3 scheduled for Descemet's Membrane Endothelial Keratoplasty (DMEK) in both eyes or with concurrent, preemptive lens replacement surgery (LRS/DMEK), if indicated as part of routine clinical practice. Each subject will go through the following two parts in this study:~• Part A without study drug administration: Part A of the study starts once LRS/DMEK of the first eye (hereafter called Eye 1) has been scheduled and subject eligibility has been confirmed. During the LRS/DMEK of Eye 1 corneal endothelium will be collected to assess the levels of selected molecular biomarkers. According to routine clinical practice, subjects will then be monitored for at least 4 weeks and up to approximately 6 months to evaluate recovery of Eye 1 prior to scheduling LRS/DMEK of the second eye (hereafter called Eye 2). The duration of the follow-up period also depends on the availability of cornea transplant material for Eye 2. Data generated during this part will serve as intra-subject control for data generated in Part B.~• Part B with study drug administration: Part B of the study starts once LRS/DMEK in Eye 2 can be scheduled and subject eligibility for Part B has been confirmed. At least 4 weeks prior to the scheduled LRS/DMEK in Eye 2, the subject will receive a single dose of QR-504a administered intravitreally in Eye 2. During the LRS/DMEK in Eye 2 corneal endothelium will be collected for molecular biomarker assessments and subjects will continue to be followed for safety and tolerability for at least 12 months post-surgery (ie, at least 13 months post dosing).
PQ-504a-001 (Fuchs Focus) is an open-label, single-dose, exploratory study to evaluate safety, tolerability, and corneal endothelium molecular biomarker(s) in subjects with Fuchs Endothelial Corneal Dystrophy with Trinucleotide Repeat Expansion in the TCF4 gene (FECD3).