OCT 12, 2019
After MIGS, Which Meds?
“We have new MIGS and we have new meds—so why can’t we put them together?” This was the question that Alex A. Huang, MD, PhD, used to open his talk at Saturday’s Glaucoma Subspecialty Day.
The challenge: While we do have theoretical answers based on our current understanding of mechanisms of action and imaging capabilities, “there aren’t any high-volume, high-quality clinical trials” that would provide a definite conclusion for patients undergoing MIGS (minimally invasive glaucoma surgery), Dr. Huang said. “Instead, there is a lot of preclinical, basic translational work that gives us a lot of promise.”
Three promising avenues. Dr. Huang summarized three current concepts:
- Proximal outflow. Although aqueous angiography shows that pilocarpine, a muscarinic agonist, increases aqueous humor outflow, current data indicate that it does not improve results following Trabectome (NeoMedix) surgery. Thus, at present, Dr. Huang said, “there is no good evidence to continue use of muscarinic agonists after Trabectome.”
- Distal outflow. Cytoskeletal-relaxing agents, such as netarsudil and other Rho kinase inhibitors, can affect distal outflow. In a preclinical study, McDonnell et al. found that the distal vessels “likely play an important role in the regulation of outflow resistance, particularly after MIGS and possibly in the pathophysiology of some forms of glaucoma.”1 Dr. Huang’s assessment: The conclusive data are not quite there yet, “but there is promise” for the use of these agents following MIGS.
- Steroid response. “What is steroid response—and how can we distinguish it from surgical failure?” Steroid response still occurs following trabecular MIGS, he said. The potential mechanism: The drugs can induce changes in scleral fibroblasts surrounding the distal outflow pathways. With regard to using steroids after MIGS, “a quick taper is recommended.”
Looking ahead. The future is bright, Dr. Huang concluded, but there is still a question about the additive effect of these drops after MIGS: “When these things come together, will 2 + 2 equal 3 . . . or 4 . . . or 5?” —Jean Shaw
1 McDonnell F et al. Am J Physiol Cell Physiol. 2018;315(1):C44-C51.
Financial disclosures: Dr. Huang: Aerie Pharmaceuticals: C; Diagnosys: S; Glaukos: S; Heidelberg Engineering: S.
Disclosure key. C = Consultant/Advisor; E = Employee; L = Speakers bureau; O = Equity owner; P = Patents/Royalty; S = Grant support.
Read more news from AAO 2019 and the Subspecialty Day meetings.