A brief but informative presentation from Mathew Vincent, Advanced cell technologies (ACT) served to remind us all that their clinical trial of an embryonic stem cell based therapy for age-related macular degeneration (AMD) is ongoing and beginning to generate more long term clinical data points. A total of 34 patients with AMD or Stargardt’s disease have been treated to date and almost 3 years have passed since the original participants were injected with the cell suspension. A clean safety profile, persistence of the cells at the site of injection and reported improvements in vision seem to bode well for the future of this trial. As by far and away the largest embryonic stem cell trial, the stem cell community eagerly awaits the publication of their results later in the year -following a very brief report in the in 2012 (1).
The ACT trial is using a cryopreserved suspension of embryonic stem cell derived retinal pigment epithelium or RPE, in AMD, RPE degenerate in a tiny but vision-critical portion of the retina known as the macular. Dr Vincent emphasised how the tiny amount of tissue required (50-200 thousand cells per dose) greatly facilitated the scale out of this therapy, ‘our therapy is easy to make’ said Dr Vincent, ‘one six-well cell culture dish (of embryonic stem cells) makes hundreds of doses… they are as easy to freeze and ship as monoclonal antibodies’.
ACT’s approach to cell storage and delivery differs to other groups who are aiming to implant the cells as fully formed functional monolayers either on synthetic scaffolds as in the the UK based, Pfizer-supported London Project to Cure Blindness (http://www.thelondonproject.org/) or as synthetic scaffold-free monolayer sheets as in the Japan based Riken institute’s induced pluripotent stem cell derived RPE. The retinal pigment epithelium are highly polarised and as an epithelial layer their barrier properties are also critical to carrying out their function. Injection of a cell suspension, Dr Vincent argued, is a significantly simplified surgical procedure.
ACT announced in 2013 that they will be testing their cryopreserved RPE suspension on a new indication –myopic macular degeneration, a disease that occurs in severely near-sighted individuals and is apparently reaching epidemic proportions in many parts of Asia. In addition the company is beginning to engineer RPE cells so that they may function in delivering enhanced concentrations of anti-inflammatory or antiagiongenic factors. There is a clear business case for this claimed Dr Vincent, where companies such as Genentech and Roche offer costly and invasive bi-monthly injections of anti-inflammatory and antiangiogenic compounds, one day-surgery to implant these hyper-activated cells could offer persistent delivery of these drugs.
Dr. Amelia Lane for Total BioPharma at the World Stem Cell and Regenerative Medicine Congress, London.
Post Doctoral Research Scientist at UCL Institute of Ophthalmology
Schwartz SD, Hubschman J-P, Heilwell G, et al. Embryonic stem cell trials for macular degeneration: a preliminary report. LANCET 2012;379(9817):713–20..