23 Feb New Drug Induces Posterior Vitreous Detachment (PVD)
A new drug, Ocriplasmin, is seeking FDA approval for treatment of some retinal disorders. Ocriplasmin (also known as microplasmin) may help patients with vitreomacular traction syndrome (VMT) and macular hole by chemically inducing a PVD.
The drug may gain Priority Review status by FDA later this year. Priority Review is a special designation for drugs that show either a significant improvement over existing therapies, or where there is not current therapy.
VMT and macular hole are two similar conditions where vitreous remains adherent to the macula causing pulling and stretching of the macular area. This physically disrupts the macula causing decreased vision and /or distortion.
Current therapy includes surgery to separate the vitreous from the underlying retinal tissue. Ocriplasmin may achieve the same goal by chemically separating this interface.
The drug has been given by intravitreal injection.
Posterior Vitreous Detachment (PVD)
The excitement in the retinal field stems from the fact that so many retinal diseases are caused by the vitreous. Many macular disorders are probably caused by interaction between the macula (retina) and the adherent vitreous.
Currently, the vitreous separates from the retina either naturally as we get older or it is induced surgically.
As we age, the vitreous proteins degenerate as does the “glue” keeping the vitreous adherent to the retina. At some point in everyone’s life a posterior vitreous detachment naturally occurs. At the time of a PVD, there is a naturally increased risk of sustaining a retinal tear. Retinal tears may develop into retinal detachments.
During surgery for many retinal diseases, surgical induction of a PVD is often helpful to achieve the surgical goal. There are, however, potential complications from pulling the vitreous away from the retina. There is a greater chance of surgically causing retinal tears!
What Does This Mean?
Chemical induction of a PVD would be a great alternative to surgery. In theory, the chance of retinal tear is greatly reduced by avoiding surgery. Hence, it is an attractive and potentially safer alternative compared to surgery because the complications may be fewer.
Just as important, however, is whether the new treatment is as effective as the current treatment. In other words, will simply injecting the new drug improve patient results as compared to surgical techniques.
If the drug gets approved by the FDA, it will be “approved” for VMT/macular holes. Once on the market, however, it will be likely be adopted for use in many other retinal conditions.
Used as an adjunct to surgery, the complication rate of retinal tears might be decreased making “surgery” much safer.