Targeting drug delivery to the suprachoroidal space in macular edema treatment

Reviewed by Steven Yeh, MD

Triamcinolone acetonide injectable suspension (Xipere; Bausch + Lomb) was launched recently as the first and only therapy approved by the FDA for use in the suprachoroidal space to treat macular edema associated with uveitis. This method of administration facilitates targeted delivery of the medication to the retina and choroid.

“This injection procedure is a more nuanced technique compared with intravitreal injections and relies on delivering the medication to the suprachoroidal space, which is a low-resistance system,” said Steven Yeh, MD, Stanley Truhlsen Jr. Endowed Chair in Ophthalmology and director of retina and uveitis service at Stanley M. Truhlsen Eye Institute at the University of Nebraska Medical Center in Omaha.

Approximately 47% of patients with macular edema associated with noninfectious uveitis have a 3-line or greater improvement in visual acuity after receiving triamcinolone acetonide injectable suspension, he reported.

Drug delivery pearls

Yeh emphasized the importance of letting patients know that this injection technique is new.

Additionally, patient selection is paramount, in that the technique is performed in patients with noninfectious uveitis with macular edema who likely will benefit from increased vision and reduced macular edema.

Yeh said he prefers to use subconjunctival lidocaine, although other physicians favor a topical anesthetic. After applying the local anesthetic and an antiseptic, such as betadine, he uses a 900 mm microneedle held perpendicular to the ocular surface to administer the drug to the suprachoroidal space.

“This allows me to maximize the short length of the needle while delivering the drug reliably into the suprachoroidal space,” he explained.

The microneedle has a circular area that will create a small dimple in the conjunctiva, which allows the tissue to displace as the needle enters the suprachoroidal space. Yeh described how he gently depresses the plunger of the microneedle and that he can feel resistance lessening as the medication enters the suprachoroidal space.

He also pointed out that the scleral has greater resistance, which can be felt if the needle is not positioned correctly within the suprachoroidal space.

“I deliver the medication with a very steady, slow, deliberate pace over about 5 seconds in contrast to a rapid injection,” he said. He advises such technique because patients may feel the expansion of the suprachoroidal space and pressure.

The Bausch + Lomb training accurately reproduces what the clinician should feel as the triamcinolone acetonide is being administered, Yeh noted.

Safety considerations

Injection of the drug into the suprachoroidal space can be associated with elevated intraocular pressure in about 12% to 14% of patients or the development of cataract in about 6% to 7% of treated and sham-treated patients, according to findings in the PEACHTREE study (NCT02595398).1

Development of endophthalmitis is also a potential adverse event, with an incidence rate of about 1 case in 2000 patients who receive intravitreal injections. Patient discomfort is possible when the drug is injected too rapidly or when the anesthesia is inadequate.

Physicians should also rule out the possibility of active infectious uveitis because of the potential for exacerbation of the disease with steroids.

“[Triamcinolone acetonide injectable suspension] is an advance in drug delivery for the treatment of macular edema associated with noninfectious uveitis,” Yeh concluded. “I am excited about the possibility of where this drug delivery platform will go, both for [patients with] uveitis as well as other patients with retinal conditions for which this platform is currently being studied.”

Steven Yeh, MD

E: Syeh@unmc.edu

Yeh is a consultant to Bausch + Lomb.

Reference

Yeh S, Khurana RN, Shah M, et al; PEACHTREE Study Investigators. Efficacy and safety of suprachoroidal CLS-TA for macular edema secondary to noninfectious uveitis phase 3 randomized trial. Ophthalmology. 2020;127(7):948-955. doi:10.1016/j.ophtha.2020.01.006