Dawn of the DED: Time to keep critters away from the ocular surface
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In honor of the popular horror movie Dawn of the Dead, I thought it would be appropriate to discuss the newest frontline treatment to combat Demodex mites, which attack the ocular surface and potentially damage our premium IOL outcomes.
No different from the 2004 remake of the movie, in which a Milwaukee Midwest neighborhood (funny, my practice is located only 40 miles from the movie location) had been overrun by the walking dead and a noncontaminated group of security guards battled the undead hordes in a local shopping mall, we finally have a treatment on the horizon to combat the dreaded Demodex mites that cause the “walking blepharitis” we see daily. So, the pun of “Dawn of the DED” (dry eye disease) is no coincidence in this modern era of pristine outcomes being desired in any location premium surgeons are caring for patients.
Demodex diagnosis
Demodex blepharitis is a large and underserved market in eye care with an estimated in-office U.S. prevalence ranging from 9 million to 25 million, as 58% of all patients in eye clinics have collarettes but only 10% to 15% of current blepharitis cases report such. Sixty-nine percent of patients with dry eye and 67% of patients undergoing cataract surgery also have Demodex blepharitis. Demodex (both folliculorum in eyelash follicles and brevis in meibomian glands) is implicated in 45% of all blepharitis cases.
Collarettes are a pathognomonic sign of Demodex infestation and are composed of mite waste products and eggs, which contain digestive enzymes that cause irritation, itching and foreign body sensation. Demodex mites are found on 100% of lashes with collarettes. Collarettes can easily be seen on the upper lid when patients look down on slit lamp exam. The Tarsus collarette prevalence study from pooled data of 1,121 patients showed that 58% of all patients seen in the clinic on slit lamp exam had collarettes and 13% of all patients on Restasis (cyclosporine, Allergan) or Xiidra (lifitegrast, Novartis) had collarettes.
Novel treatment to eradicate Demodex mites
TP-03 (Tarsus) is a novel therapeutic drop designed to paralyze the mite nervous system through parasite-specific GABA inhibition with lotilaner, a highly lipophilic molecule with increased uptake in the oily sebum of the hair follicle where mites reside.
In the phase 2b Europa clinical trial with twice-daily dosing of TP-03, statistically significant results were achieved for the primary endpoint of collarette cure by 80% of participants on TP-03 compared with 16% on vehicle (P < .001) at day 42, and the secondary endpoint of mite eradication was achieved by 73% of participants on TP-03 compared with 21% on vehicle (P = .003) at day 42. TP-03 was well tolerated, and there were no reports of serious adverse events or treatment discontinuations due to adverse events. Participants in Europa rated the administration of the eye drops as “neither comfortable nor uncomfortable,” “comfortable” or “very comfortable” 87% of the time.
Currently, there are two pivotal phase 3 larger multicenter clinical trials, Saturn-1 and Saturn-2, which actively began enrolling patients with similar criteria endpoints as the Europa study. Initial data from phase 2 studies show a recurrence rate of clinical grade blepharitis at around 6 months post-therapy, suggesting that TP-03 will give Demodex blepharitis relief for at least 6 months, with another round of therapy required for recurrences.
Currently, there is no approved therapy for Demodex blepharitis, which can affect and exacerbate dry eye disease, which in turn can affect our premium surgical outcomes if undiagnosed from the outset. It is reassuring that in the near future these critters from Dawn of the DED will be treatable and not overtake our premium surgical outcomes.
- References:
- Gao YY, et al. Invest Ophthalmol Vis Sci. 2005;doi:10.1167/iovs.05-0275.
- Wilson FA, et al. J Ophthalmol. 2015;doi:10.1155/2015/435606.
- Zhao YE, et al. Ophthalmic Epidemiol. 2012;doi:10.3109/09286586.2011.642052.
- For more information:
- Mitchell A. Jackson, MD, can be reached at Jacksoneye, 300 N. Milwaukee Ave., Suite L, Lake Villa, IL 60046; email: mjlaserdoc@msn.com.
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