Abstract
Purpose:
Bamosiran (SYL040012) is a new drug being developed by Sylentis (Zeltia Group) for the treatment of elevated intraocular pressure (IOP) and/or glaucoma. Preclinical and clinical studies are shown in this work to demonstrate that bamosiran has low bioavailability in systemic tissues whereas high levels are found in the eye.
Methods:
A Pharmacokinetic clinical study has been carried out in healthy volunteers to evaluate the levels of bamosiran after administration as eye drops during 7 consecutive days. Additionally, biodistribution studies have been performed in New Zealand White rabbits (N~100) to measure the levels of bamosiran in eye structures.
Results:
High presence of bamosiran have been detected in lacrimal gland, cornea, iris and ciliary body of animals and further analyses demonstrated the delivery of bamosiran to the intracellular compartment of these tissues where it interacts with its target:the mRNA precursor of beta2 adrenergic receptors. Bamosiran was not detected (> LLOQ) in plasma at any of the doses tested in the clinical trial.<br /> These levels are explained by its nature. Bamosiran is an RNAi based treatment sensible to plasmatic RNAases. On the other hand, bamosiran is more stable in ocular fluids, with lower levels of RNAases. Hence, bamosiran has a higher half-time in the eye.This specific feature differentiates bamosiran from Beta Blockers which can interact with any beta2 adrenergic receptor in the body. Bamosiran does not interact or block these receptors, just regulates its synthesis at the ocular level without affecting receptors of systemic tissues thus minimizing the possibility to produce side effects.<br /> Bamosiran is currently in Phase 2 clinical trials against comparator (NCT02250612, EudraCT No: 2013-002947-27). In previous clinical studies, it demonstrated statistically significant reduction in IOP when compared to placebo. The AEs reported in previous clinical trials related to bamosiran were not different from those reported for placebo. This correlates well with its low half-life in systemic tissues and plasma.
Conclusions:
Bamosiran in a unique drug in its class being developed for treatment of elevated IOP and it could open a door to new treatments with very low local side effects and without systemic side effects. This could be extremely important for management of glaucoma in sensitive populations such us pregnant woman, children or elderly people.