A Study Investigating the Safety, Tolerability, and Efficacy of Elamipretide Topical Ophthalmic Solution for the Treatment of Fuchs' Corneal Endothelial Dystrophy (FCED)

Incidence and Severity of Ocular TEAEs.

Time frame · Screening Visit, Baseline (Day 1), Week 1, Week 4, Week 8, Week 12, and Week 16

The incidence and severity of ocular treatment emergent adverse events (TEAEs)

The Incidence and Severity of Systemic Adverse Events

Time frame · Screening Visit, Baseline (Day 1), Week 1, Week 4, Week 8, Week 12, and Week 16

The incidence and severity of systemic treatment emergent adverse events (TEAEs)

Change From Baseline in Findings From Slit Lamp Examinations (SLE) Part A

Time frame · Baseline, Week 1, Week 4, Week 8, Week 12, and Week 16

Number of participants who had a change from baseline from normal or abnormal not clinically significant, to abnormal clinically significant (CS) findings for slit lamp examinations (SLE) for Part A. Part B is reported as separate outcome since unit of measure is number of eyes.

Change From Baseline in Findings From Slit Lamp Examinations (SLE) Part B

Time frame · Baseline, Week 1, Week 4, Week 8, Week 12, and Week 16

Number of eyes with a change from baseline from normal or abnormal not clinically significant, to abnormal clinically significant (CS) findings for slit lamp examinations (SLE) for Part B. Part A is reported as separate outcome.

Change From Baseline in Intraocular Pressure (IOP) for Part A

Time frame · Baseline, Week 1, Week 4, Week 8, Week 12

Change from Baseline in intraocular pressure (IOP) using Goldmann applanation tonometry for Part A

Change From Baseline in Intraocular Pressure (IOP) for Part B

Time frame · Baseline, Week 1, Week 4, Week 8, Week 12 , and Week 16 or early discontinuation visit

Change from Baseline in intraocular pressure (IOP) using Goldmann applanation tonometry for Part B. Part A is reported separately.

Change From Baseline in Central Corneal Thickness by Visit Part A as Measured by Pachymetry for Part A

Time frame · Baseline, Week 1, Week 4, Week 8, Week 12, and Week 16

Change from Baseline in Central Corneal Thickness by Visit as measured by Pachymetry for Part A. Part B is reported as a separate outcome measure.

Central Corneal Thickness Part B

Time frame · Baseline (Day 1), Week 1, Week 4, Week 8, Week 12, and Week 16, or Early discontinuation visit

Central Corneal Thickness: by-subject data as measured by Pachymetry and Pentacam. Part A is reported as a separate outcome measure.

Change From Baseline Endothelial Cell Hexagonality in Percentage Over All 12 Weeks for Part A

Time frame · Baseline, Week 1, 4, 8, and 12

Change From Baseline in Endothelial Cell Hexagonality in Percentage Over All 12 Weeks for Part A. Specular microscopy is a noninvasive photographic technique that allows visualization and analyzation the corneal endothelium. Using computer-assisted morphometry, specular microscopes analyzes the size, shape and population of the endothelial cells. Histologically, healthy corneal cells initially have a hexagonal shape. As endothelial cells die, neighboring cells enlarge to cover the empty space once occupied by the cell. This, in turn, causes the remaining cells to lose their hexagonal shape. Assessments were performed using the flex center and full auto methods for Part A and data from the flex center method was summarized. The flex center method was used for Part B. The percent of Part B is entered as a separate outcome measure. A decrease from baseline in % cell hexagonality means worse outcome, a increase from baseline means better outcome.

Corneal Endothelial Cell Hexagonality Part B

Time frame · Baseline, Week 1, Week 4, Week 8, Week 12, and Week 16 or early discontinuation visit

Corneal Endothelial Cell Hexagonality in Percentage by-subject data: Part B. Data was only listed in weeks where images were good enough quality to quantify. Specular microscopy is a noninvasive photographic technique that allows visualization and analyzation the corneal endothelium. Using computer-assisted morphometry, specular microscopes analyzes the size, shape and population of the endothelial cells. Histologically, healthy corneal cells initially have a hexagonal shape. As endothelial cells die, neighboring cells enlarge to cover the empty space once occupied by the cell. This, in turn, causes the remaining cells to lose their hexagonal shape. The flex center method was used for Part B. A decrease in percent of cell hexagonality from baseline means worse outcome, an increase from baseline means better outcome.

Change From Baseline in Best Corrected Visual Acuity (BCVA) Using the Early Treatment Diabetic Retinopathy Study (ETDRS) Scale for Part A.

Time frame · Baseline, Weeks 1, 4, 8, 12, and 16

Best corrected visual acuity (BCVA) using the using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale by visit. ETDRS charts present a series of five letters of equal difficulty on each row, with standardized spacing between letters and rows; there is a total of 14 lines (70 letters), with letter size increasing further geometrically and equivalently in every line by a factor of 1.2589 (or 0.1 log unit), moving up the chart. Minimum score of zero, maximum score of 100. Change from baseline: a more negative score is worse outcome, a more positive score is better outcome. A lower score means less letters were read correctly (worse outcome) and a higher score means more letters were read correctly (better outcome). Part B was listed separately.

Best Corrected Visual Acuity (BCVA) Score Using ETDRS Scale for Part B

Time frame · Baseline, Weeks 1, 4, 8, 12, and 16

Best corrected visual acuity (BCVA) using the using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale by visit. ETDRS charts present a series of five letters of equal difficulty on each row, with standardized spacing between letters and rows; there is a total of 14 lines (70 letters), with letter size increasing further geometrically and equivalently in every line by a factor of 1.2589 (or 0.1 log unit), moving up the chart. Minimum score of zero, maximum score of 100. Change from baseline: a more negative score is worse outcome, a more positive score is better outcome. A lower score means less letters were read correctly (worse outcome) and a higher score means more letters were read correctly (better outcome).

Change From Baseline in Endothelial Cell Density Over All 12 Weeks for Part A

Time frame · Baseline, Weeks 1, 4, 8, and 12

Change From Baseline in Endothelial Cell Counts, or density (Counts/mm\^2) over all 12 weeks for Part A. Part B is entered as a separate outcome measure.

Corneal Endothelial Cell Density Part B

Time frame · Baseline, Weeks 1, 4, 8, 12, and 16.

Corneal Endothelial Cell Density: Part B, By-subject data for all time points where images were readable. For all time points where there were "Poor Quality Images" or "too few cells to register", there were no data available, and these were not listed below.

Change From Baseline in Endothelial Cell Coefficient of Variation Over All 12 Weeks for Part A

Time frame · Baseline, Week 12

Change From Baseline in Endothelial Cell Coefficient of Variation Over All 12 Weeks. Coefficient of variation (CV) is Standard deviation (SD) of cell area divided by the mean cell area of endothelial cell analyzed. CV represents the coefficient, or degree, of variation in the sizes of the endothelial cells (polymegethism). By measuring the variation in size between endothelial cells, the system can measure how much cell loss is occurring. The more variation, the worse the outcome. Part B is is entered as a separate outcome measure.

Coefficient of Variation (CoV) Part B

Time frame · Baseline, Weeks 1, 4, 8,12, and 16

Part B, By-subject data for all time points where images were readable. For all time points where there were "Poor Quality Images" or "too few cells to register" there were no data available. CoV represents the coefficient, or degree, of variation in the sizes of the endothelial cells. By measuring the variation in size between endothelial cells, the system can measure how much cell loss is occurring. A CoV less than 40 is normal.