TLC399 applies sustained release technology for the treatment of macular edema secondary to retinal vein occlusion (RVO), designed to provide benefits for a much longer duration than existing therapies and to thus reduce the administration frequency.

Approximately 16 million people worldwide may have macular edema with retinal vein occlusion, a disease of the retina that causes impaired vision, characterized by leakage of fluid from the blood vessels in the retina. Current therapies for this type of macular edema include an injection into the eye that may be required every one or two months.

TLC399 applies TLC’s BioSeizer® technology to allow sustained release of the corticosteroid dexamethasone and is designed to provide effects lasting as long as six months between injections.

Preliminary clinical data from an early study of TLC399 have demonstrated its potential to decrease the thickness of the retina and improve vision.


TLC399 is our proprietary BioSeizer® formulation of dexamethasone sodium phosphate (DSP), intended as an intravitreal, or in-eye, injection for the treatment of macular edema due to retinal vein occlusion. TLC399 in preclinical models has been shown to provide therapeutic levels of DSP in the eye for at least six months after a single administration. A Phase I/II safety trial has demonstrated encouraging signs of efficacy in both the reduction of retinal central subfield thickness and improvements in visual acuity. A larger randomized, double-blind, dose finding Phase II trial is underway. We are also evaluating opportunities to develop TLC399 in diabetic macular edema in combination with intravitreal anti-VEGF drugs.



Dexamethasone sodium phosphate

DDS Platform



Macular edema


  • Rapid onset
  • Designed to achieve prolonged sustained release duration beyond six months
  • Smaller administration needle to reduce risk of conjunctival hemorrhaging and infections

Development Status

Phase II