EURETINA 2023: Safety and efficacy through week 48 in the Phase 2a STARLIGHT clinical trial

The 23rd annual EURETINA Congress is underway in Amsterdam, the Netherlands. We spoke with Michael Singer, MD who provided an overview of his presentation and his work with Nanoscope Therapeutics, "MCO-010 Optogenetic Therapy to Treat Stargardt Disease: Safety and Efficacy through Week 48 in the Phase 2a STARLIGHT Clinical Trial."

Here's what he had to say about the meeting and his research.

Audio Transcript

Editor's note - This transcript has been edited for clarity.

Sydney Crago: I'm joined today by Dr Michael Singer, who is presenting at the upcoming EURETINA conference in Amsterdam. He'll be talking a bit today about the STARLIGHT clinical trial. Dr Singer, can you tell us about your presentation?

Michael Singer, MD: Sure. The presentation is on the STARLIGHT clinical trial, and the STARLIGHT clinical trial features a multi-chromatic opsin, which is essentially is an intravitreal injection of a AAV-2 vector, which essentially convert bipolar cells into photoreceptors. It is already been studied in the RESTORE trial for gene-agnostic retinitis pigmentosa, and showed impressive gains in low, low vision, visual acuity in the multi-luminance ability testing and multi-luminance state discrimination in a number of patients over a year's period of time. So we wanted to take this same molecule and see if we could apply it to Stargardt disease.

And essentially, patients were given an injection of this AAV-2 to vector by intravitreal injection, and it was set up that patients were given this medicine and then followed over 24 weeks for the primary endpoint and 48 weeks for the end of study. And this essentially was a safety study. Patients were given an oral steroid prophylaxis regimen. And the primary endpoint was safety and tolerability as I said before, but secondary endpoints are BCVA and visual field perimetry, as well as an exploratory endpoint of the Michigan retinal degeneration questionnaire.
There were six patients all of them were ABCA4 positive, however, the reality was was half of them had macular disease and half of them had peripheral disease. So you know, half of these patients had the phenotype associated with what we think of Stargardt's being: A macular degeneration. In terms of safety, it was very well tolerated, with no patients with retinal vasculitis or retinal occlusive disease and small numbers of patients about a third of patients with vitreous cells. And just the other things you typically see in an individual injection of AAV-2 to vector. When we look at the secondary endpoint. We look at patients with, best-corrected visual acuity, we really have to hone in on the patient with the macula phenotype, because these patients were the ones that really seemed to work the best. And 2 out of these 3 patients, were able to gain greater than 7 letters with the regular visual acuity of use a low luminance magnifier, 3 out of 3 patients in the macro phenotype gain greater than 30 letters. So it really had a positive effect on visual acuity.

When we look at, when we look at it overall, we look at the fact that essentially, the visual field 50% of patients improved in their visual field perimetry. And if you look from a quantitative standpoint, the mean improvement of [all patients was 2.6 decibel.] So essentially, their visual field got better. And they were able to identify more points on the visual field process. The other thing was the exploratory endpoint. When we looked at what's called the Michigan retinal degeneration questionnaire, patients with the treatment, with the start, with the macular phenotype, seem to have an improvement in the key domain scores, which is really important, the ones that really matter, which is reading and color and content. So again, these patients seem to do very well on the questionnaires going forward.

So what was what was nice about it was well tolerated at 48 weeks, which was similar to the 24 week process. Like I said before, people with the macular variant seem to do much better. And there was a 5.5 letter proven EDTRS. And the 13 letter improvement with the with the magnifier, overall in the overall population and 2.63 decibel improvement in visual fields. And there were improvements in reading and color contrast by the Michigan study. So overall, this seems to have lots of promise. And for these patients that are desperate to have something, this seems to be the next generation of medications. We're not only where we're stabilizing medicines, which a lot of therapies for inherited retinal diseases are doing. There's a potential for increased vision, whether it's visual acuity as measured by a chart, or more functional visual acuity, measured by quality life.