NCX 1741, a Novel Nitric Oxide-Donating Phosphodiesterase-5 Inhibitor, Exerts Rapid and Long-Lasting Intraocular Pressure-Lowering in Cynomolgus Monkeys.

We studied the IOP-lowering effects of NCX 1741, a novel nitric oxide (NO)-donating derivative of the phosphodiesterase type-5 inhibitor, avanafil, in Cynomolgus monkey with laser-induced ocular hypertension (OHT-monkeys). NCX 1193 (NO-donating moiety), NCX 1744 (NCX 1741 without ester nitrate moiety), and travoprost (PGF2α analogue) were used for comparison. Ocular exposure after NCX 1741 dosing also was addressed. Vehicle (phosphate buffer pH 6.0, Kolliphor 5%, DMSO 0.3%, benzalkonium chloride 0.02%), NCX 1741, NCX 1193, NCX 1744, or travoprost were instilled (30 μL; single dose) masked and conscious IOPs were measured by pneumatonometry. LC-MS/MS-based methods were employed to monitor ocular exposure of NCX 1741 and main metabolites after ocular dosing in New Zealand White rabbits. NCX 1741 (2.2%, 0.8 μmol/eye) lowered IOP with an E (ΔΔIOP, IOP change vs. pre-dose and vehicle) between 5 and 8 h post-dosing (ΔΔIOP, -5.3 ± 2.0 mmHg and ΔΔIOP, -6.0 ± 2.1 mmHg). Conversely, equimolar (0.47%, 0.8 μmol/eye) NCX 1193 IOP-lowering effects were maximal 3 h post-dosing (ΔΔIOP, -4.7 ± 1.6 mmHg) and declined thereafter (ΔΔIOP, -1.6 ± 1.1 mmHg). In a follow-up study, NCX 1741 (1.5%, 0.5 μmol/eye) was more effective than NCX 1744 despite a similar duration. Further, NCX 1741 was as effective as travoprost (0.1%, 0.06 μmol/eye) at 5 and 8 h post-dosing (travoprost, ΔΔIOP, -3.4 ± 2.2 mmHg and ΔΔIOP, -4.9 ± 1.3 mmHg) but had shorter duration (NCX 1741, ΔΔIOP, -1.5 ± 1.1 mmHg; travoprost, ΔΔIOP, -7.1 ± 2.8 mmHg). NCX 1741 resulted in significant aqueous humor exposure, as determined by the levels of the main metabolite, avanafil. NCX 1741 rapidly and effectively lowers IOP in OHT-monkeys for several hours post-dosing. How these effects translate in humans is still to be defined.