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Abstract

Background
The primary aim of the SAMADI [SAponins for MAcular DIsease] trial is to establish whether treatment of age-related macular degeneration (AMD) with oral saponin supplements is feasible and acceptable to participants. AMD is a progressive disease, which results in the death and dysfunction of cells in the outer retina. One potential contributor to AMD progression is the reduced permeability of Bruch’s membrane underlying the retina. Saponins have a structure enabling them to assist dispersal of lipid deposits in Bruch’s membrane, providing a rationale for the proposed intervention in AMD. Secondary aims are to provide an estimate of the variability of a proposed future primary outcome, and to provide estimates of treatment effects of clinical outcomes.

Methods
SAMADI is a double masked randomised feasibility trial, which will recruit 60 participants with early or intermediate AMD in at least one eye. Participants will be randomly assigned into one of two groups, one receiving the oral saponin tablets and the other placebo tablets (indistinguishable in appearance), both to be taken daily for 4 months. Participants and research optometrists will be masked to the allocation. Clinical tests will be repeated at baseline, 4 months and 12 months. The primary outcome measures relate to feasibility of the following aspects of the intervention and study design: (1) recruitment and retention over 4 and 12 months; (2) adherence to treatment and acceptability of intervention; (3) the eligibility assessment process; (4) collecting the outcome data. The rate of serious adverse events will be an additional primary outcome measure.

Secondary outcomes include dark adaptation metrics, best corrected visual acuity, contrast sensitivity, fundus imaging, low luminance questionnaire, standard electroretinograms according to International Society for Clinical Electrophysiology of Vision standard protocols, and imaging retinal densitometry (at one site only).

Discussion
The data will be used to determine the feasibility of the trial design, how well participants complied with taking the tablets, and the potential effectiveness of the treatment. If feasible, this information will be used to inform a larger trial, which will definitively assess how effective the treatment is in participants with AMD.

Publication Type:	Article
Additional Information:	©The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Publisher Keywords:	Randomised controlled trial, Age-related macular degeneration, Saponins, Feasibility study
Subjects:	R Medicine > RE Ophthalmology
Departments:	School of Health & Medical Sciences School of Health & Medical Sciences > Department of Optometry & Visual Science
SWORD Depositor:	Symplectic Administrator

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