Dante J. Pieramici, MD, and Lloyd Clark, MD, provide insight on approaching the treatment of wet AMD with intravitreal injections and discuss creating a tailored treatment regimen for patients.
John W. Kitchens, MD: Dante, what’s our end point for these patients with wet AMD [age-related macular degeneration] as we’re treating them?
Dante J. Pieramici, MD: As I mentioned, I tell the patients up front, we’re not going to cure your wet macular degeneration with these drugs. It’s not like you’re going to do a 10-day course of antibiotics, and then you’re done. It’s going to be an ongoing treatment. How many times are you going to need this treatment? We’ll find out over time. As we start treating you, we’ll be watching your vision, doing the OCT [optical coherence tomography] imaging, and deciding how long can we extend your therapy. Most of the patients get out to somewhere between 6 to 8 weeks of therapy. There are some who can go more and some who can go less. That’s what I give them, but they need to realize that if we want to maintain their vision, we need to stick to this treatment regimen, and we need to see them because what can happen, if we look at real-world data outside of the clinical trial data, we see that patients do well initially. But if we follow them, 6 months or a year or 2 or 3 later, they sometimes have regressed and lost the vision. It seems like it’s because they’re not getting enough therapy in the long run. There’s an association between the lower number of injections and the visual outcomes. We want to try to motivate them to keep coming in and getting the therapy. It’s driven some of the new developments in technology and things for the second generation of anti-VEGF agents.
John W. Kitchens, MD: Lloyd, Dante, everybody’s described this effect of improving the vision with this loading dose, getting patients stable, and then extending these patients out. How long does it take that patient to see tangible results, to get stable, to get their vision restored as much as possible? Then once they’re at that phase, how often are they receiving treatment on average?
Lloyd Clark, MD: This is a class effect. When we look at these drugs in multiple randomized clinical trials, it looks like you get most of the anatomic benefit after about 3 injections, maybe 4. There are going to be outliers in both directions, but a good yardstick is with around 3 monthly injections, you’re going to see the lion’s share of clinical benefit. On the other hand, if you don’t see much response, you might be using the wrong agent. That’s a good pearl to think about switching agents. There has been this idea in the retina field, 3 injections and then reevaluate, and there is evidence to suggest that that makes sense based on the OCT curves in the randomized clinical trials. I’d say that your typical patient in clinical practice will get 3 monthly injections. If they’ve had a nice clinical response with drying of the macular edema, resolution of the intraretinal and subretinal fluid, then at that point we can adopt Dante’s treat and extend that most of us now use to increase the intervals between the injections, with the goal of getting these patients out as far as they can. Now, some people may use a little longer loading period, maybe 4 months, 6 months. The concept is the same. You treat monthly until dry, and then try to extend the intervals to an appropriate level that keeps the retina dry, maintains the visual gains, but suppresses retinal fluid. On average, maybe 3 or 4 months of monthly treatment.
John W. Kitchens, MD: Then once you get those patients stable, are they getting on average, do you think 6, 7, 8 injections a year?
Lloyd Clark, MD: This is tough to evaluate in clinical trials, but we now have a number of retrospective studies, either from EMR [electronic medical record] databases or the IRIS [Intelligent Research in Sight] registry, for example, is a great tool that’s used for quality reporting for Medicare. It looks like the break point for good outcomes for patients is somewhere between 6 and 7 injections in a year. It’s reasonable to shoot for that. That gets to what Dante was saying earlier, maybe a 6- to 8-week interval where most patients can be maintained. That gets you to around 6, 7, 8 injections over the year. With that number the average patient can do quite well for a long time with wet macular degeneration. They can maintain their vision gains for many years.
Transcript Edited for Clarity