Biochemistry, Genetics and Molecular Biology› Molecular Biology› Retinal Development and Disorders

Stargardt macular degeneration — Subretinal hESC-derived retinal pigment epithelial cells

Submitted 2026-10-22

Field: Biochemistry, Genetics and Molecular Biology › Molecular BiologyType: No effect foundArea: stargardt macular degenerationTarget: Subretinal hESC-derived retinal pigment epithelial cellsStage: phase 1

Hypothesis

Transplanting embryonic-stem-cell-derived RPE cells under the retina would be safe and could improve visual function in advanced Stargardt disease, as earlier trials reporting acuity gains suggested.

What failed

In 12 participants given up to 200,000 cells, there was no uncontrolled proliferation or inflammation, but microperimetry showed no benefit at 12 months, small acuity gains in 4 people were not sustained or were matched in the untreated eye, and quality of life did not change. At the highest dose one eye showed local retinal thinning and lost sensitivity.

Broken assumption

Visual-acuity gains reported in earlier RPE transplant trials reflected real structural and functional benefit in the treated retina.

Why

The authors note the subretinal pigment may mean surviving cells or only released pigment, and that at this advanced, slowly progressing stage any protective effect might only show after much longer follow-up.

From the published paper: Mehat et al. Ophthalmology, 2018. ↗CC BY

Research ideas from this failure

Unvetted lead — read the papers

New hypotheses this failure suggests, each with a crucial experiment, a rival explanation of the original result, and the papers it rests on. Written by AI from paper titles and abstracts found on OpenAlex (and Europe PMC, for life and health sciences).

Related failures (1)

Matched on shared genes, mechanisms and ways of failing as well as wording. Each shows why it matched — treat these as leads rather than verdicts.

nephrotic syndromeLow-dose interleukin-2 (IL2)different research area
Low-dose IL2 raises regulatory T cells, which reverse protein loss in the urine in animal models of nephrotic syndrome, so it would lower protein loss in children whose nephrotic syndrome resists all other drugs.
In 5 boys given six monthly cycles, IL2 raised regulatory T cells in some, but protein in the urine and kidney function did not change at any point. One child had an asthma attack after the first dose.
Why it matched: mechanism: Inflammation & innate immunity

Links in published research

Where this experiment's genes are known to matter outside its own research area, and the papers behind those links. Sources: Open Targets Platform and Europe PMC.