Types of Geographic Atrophy

Many years ago, when I was in college, I had a professor who talked about “griping in the gut”. His point was this: The precision of medical diagnosing and treatment has come a long way and it still has a long way to go.

A while ago patients were diagnosed with "griping in the gut". It could have been an ulcer or stomach cancer or appendicitis. All that was sure was the patient had belly pain, aka "griping in the gut".

Ophthalmological advancements for macular degeneration

Fast forward to 2020 and ophthalmology. A great deal of progress has been made beyond a simple pronouncement of blindness. However, we still have a long way to go.

A few years back, I was following Lampalizumab trials pretty closely. At that time Lampalizumab was being considered the front runner in the race to be the first, real treatment for geographic atrophy. Things went really well until phase 3 trials at which point everything went to Hades.

Genetics and anti-VEGF clinical trials

Because the earlier clinical trials had such good results, there was some speculation the sample group was somehow different from the norm. The last I followed it, they were looking at genetic data to see if they had inadvertently gotten ahold of a group of people with the same genotype.

Was it possible there was not one type of geographic atrophy but two or three or a dozen different types? Would that account for different responses to a treatment?

What's the role of genes?

Definitely intriguing and definitely possible! In fact, recently IOVS, Investigative Ophthalmology & Visual Science published some research being done by Marc Biarnes Perez and colleagues. It would appear there are at least three different groups possible.

Research on macular degeneration genetic groups

The groups differ in several, specific ways. The observable expression of the genes, called phenotype, suggests there are different gene configurations, called genotype, underlying them. In between the genotype and the phenotype, there may be different mechanisms at play. For example, maybe different genotypes have different errors in the innate immune system or lipid formation. Both the innate immune system and lipids play roles in geographic atrophy.

Is precision medicine the answer to treating macular degeneration?

Know the phenotype, find the gene and identify the errors, and one day it may be possible to target your own, personal type of geographic atrophy with a designer treatment just for you...and everyone else with that type. Pretty cool.

Maybe, but not yet

Of course, I did say one day. And it is not next Tuesday. Right now, much of pharmacology is in the “killing an ant with an elephant gun” phase. You have a general idea where your target is but your weapon is not precise enough to just specifically aim at that one thing.

Eye injections are a relatively recent medical breakthrough

For a while, we are going to have to be happy with the one-size-fits-all approach to treatment. As I said someplace before (I get so confused!), the first anti-VEGF treatment for wet AMD was only introduced in 2004. We cannot get too impatient about these things even though we would like to.

Eye treatments will get better

Our aim, however, is getting better all of the time. Research like that done by Biarnes Perez and others is getting us closer to our targets all of the time¹. It really is just a matter of time before vague diagnoses and treatments, like "griping in the gut", are in our past. Now that is progress!