Inotek Pharma (ITEK) is not starting 2017 in a good place.

The Lexington, Mass.-based biotech company said Tuesday that an experimental treatment for glaucoma failed to fully demonstrate superiority over placebo in a phase III clinical trial.

The setback for the Inotek drug, trabodenoson, caused shares to fall 64% to $2.20 in premarket trading.

"We are disappointed that the primary endpoint of superiority at all 12 time points was not achieved," said Inotek CEO David Southwell, in a statement. "This result was driven primarily by the unexpectedly stronger placebo response at the 8 a.m. time point."

Inotek hoped to show trabodenoson could lower pressure in the eye better than placebo in patients with glaucoma. Researchers conducting the company's phase III study measured eye pressure in patients four times per day after 24, 42 and 84 days of treatment.

The study failed because the difference in eye pressure between trabodenoson and placebo at the 8 a.m. time points was not statistically significant, the company said.

Trabodenoson did achieve some secondary efficacy endpoints in the phase III study, but for now, Inotek is waiting to collect additional data before deciding how to move forward, if at all. The company is already conducting studies that combine trabodenoson with another glaucoma medicine.

Inotek is not the only company to run into trouble with the development of glaucoma drugs. Manufacturing issues have forced Aerie Pharmaceuticals(AERI) - Get Report to delay an approval filing for its glaucoma drug Rhopressa until the end of the first quarter. The marketing application is supported by mixed results from phase III studies.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.