The phase 2 clinical trial of Ocular Therapeutix’s drug-eluting insert didn’t end in tears, but in this case, that translated to the opposite of success for the proposed treatment for dry eye disease.
Ocular said this week that the OTX-CSI insert failed to achieve its primary endpoint in the randomized, controlled study, which observed the effects of the insert over varying periods of use in a group of nearly 150 patients.
The OTX-CSI device is a small, hydrogel capsule that’s positioned inside the canaliculus, the short channel in the inner corner of the eye where tears drain into the tear sac, to block the eyelid’s punctum, where tear fluid is pumped out of the eye. Once in place, the insert slowly releases a dose of cyclosporine, an immunosuppressant that’s used to increase tear production that has been inhibited by inflammation in the eye.
The completely biodegradable insert is intended to stay in place for up to 12 weeks, administering a sustained dose of the drug throughout that entire period.
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In the phase 2 trial, participants were split into four groups: two that received the drug-eluting OTX-CSI insert for either two to three months or three to four months, and two that received only the insert, sans cyclosporine, for either one week or three to four months.
After the study period and a four-week safety follow-up for all participants, the researchers concluded that participants in the OTX-CSI groups hadn’t experienced any greater improvement in tear production than those in the control group.
In fact, those in the control group were producing more moisture after the 12-week study period. That was determined using the standard Schirmer’s Test, in which a strip of filter paper is placed inside the lower eyelid to measure moisture. After the treatment period, both of the OTX-CSI groups registered levels below 2 millimeters on the test scale, compared to 2.24 millimeters and 3.08 millimeters for the long and short control groups, respectively.
Though the researchers said they did see improvements in some other signs and symptoms of dry eye disease in the OTX-CSI users, they weren’t statistically significant when compared to the control group.
“While we are disappointed by these results, demonstrating clinical benefit in patients with dry eye disease remains a significant unmet need and we will continue to review the data for additional information that may inform future development of this program,” Ocular CEO Antony Mattessich said in a statement. “We remain confident in the potential of our hydrogel-based formulation technology and its ability to deliver innovative ophthalmology therapies.”
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Ocular has faced similar roadblocks before. In 2019, it reported the trial failure of another of its products, the OTX-TP insert to treat glaucoma. Designed similarly to Ocular’s dry eye disease insert, OTX-TP was a hydrogel plug placed within the tear duct for continuous delivery of the glaucoma drug travoprost for 12 weeks.
In a phase 3 trial, however, the insert fell short of its goal of consistently reducing average intraocular pressure. The primary endpoint of the clinical study required the insert’s users to experience lower pressure at nine checkpoints throughout a single day; OTX-TP achieved statistically significant reductions compared to the placebo at only eight of the nine time points.