Investigational Gene Tx Improves Diabetic Retinopathy Severity at 1 Year

A one-time in-office injection of an investigational gene therapy stabilized or improved diabetic retinopathy for up to a year, particularly in patients with nonproliferative diabetic retinopathy (NPDR), according to results of the ALTITUDE trial reported at the American Academy of Ophthalmology annual meeting.

In this exclusive MedPage Today video, lead investigator Mark R. Barakat, MD, of Retinal Consultants of Arizona in Phoenix, describes the results and future potential of this treatment.

Following is a transcript of his remarks:

Thanks so much for having me. We’ll be talking a little bit about the ALTITUDE trial, which of course is a phase II trial about AbbVie RGX-314, which is an AAV [adeno-associated virus] 8 vector, which encodes a monoclonal antibody for an anti-VEGF [vascular endothelial growth factor].

And this is a phase II trial for subjects with moderately severe, severe NPDR, and mild PDR [proliferative diabetic retinopathy]. They received one suprachoroidal injection, a one-time injection within the clinic, and then are followed for a year’s time, and with treatment as needed per physician directive. This is a dose-escalating trial, so these are results of the first two doses — so of course, one through three.

Importantly, this was safe. You always worry about, especially with gene therapy, inflammation, and there was a mild rate of about 12% of episcleritis, mild to moderate, 6% of intraocular inflammation, also mild, easily managed with topical therapy.

The main question, really the primary outcome, is progression in terms of disease severity, so DRSS [Diabetes Retinopathy Severity Scale] scores. And so in comparison to the control arm, as you might expect, the control arm got worse. About 37% or so had two-step worsening.

Now, in dose level one, that narrative is flipped, and so you have about 33% that actually had a two-step improvement. And in dose level two, you have about 20% that had a two-step improvement. And importantly, none had any worsening. If you look at just any improvement, there were some in the control group — about 25% of two thirds in a dose level one and 70% in dose level two with no worsening.

Now that’s all well and good. You need to have an approvable endpoint for the FDA. But ultimately as a physician, what do you care about? You care about disease and you care about vision-threatening events. In this case, vision-threatening events, progression of proliferative diabetic retinopathy, and secondary neovascularization, also DME [diabetic macular edema], of course.

And so if you look at the control group, about 37% had progression to vision-threatening events. And in dose level two, it went all the way down to 4.2%. So an 89% reduction with a one-time in-office treatment that was well tolerated over the course of 1 year.

And so the ramifications of this, of course, are if you have something that can be administered one time in the office, in a safe manner, in a patient population that we tend not to treat because of the treatment burden that’s required in frequent anti-VEGF injections, that might change the paradigm of how we approach these patients going forward.

So, of course, there are more doses to come. This was done in the absence of steroid prophylaxis, so this is something else that needs to be discussed. But this is very exciting data.

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