Eyelid mites no match for Tarsus eye drop, as phase 3 data spur drive to FDA

Tarsus Pharmaceuticals says mites are no match for its novel eye drop, posting positive phase 3 data that the company intends to ride all the way to regulators later this year. 

The drug, TP-03, is an eye drop formulation of lotilaner, an anti-parasitic drug used in pets to treat mange. Tarsus is re-purposing the therapy to treat Demodex blepharitis, an eyelid disease caused by mites that affects 25 million Americans. TP-03 was found to be effective at reducing mites and collarettes, a waxy build-up on the eyelids, in top-line data released Monday.

Nearly 20% of patients reported having a complete composite cure, defined as virtually no collarettes and no eyelid redness. Tarsus plans to wrap these data up in a bow to apply for a new drug application with the FDA in the second half of this year. 

CEO Bobak Azamian, M.D., Ph.D., said he was eager to have these results in hand after positive phase 2 data teed up a regulatory pathway pending the success of the phase 3 test. The med was able to meet the high bar set forth by regulators, who have been “clear and consistent” in their guidance. Now, the company is on the cusp of achieving commercial use for TP-03.

“Imagine going from 100 collarettes per lid down to 0, 1 or 2,” he said. “They’ve held us to a very high bar and a very objective standard for a first-ever drug for the treatment of Demodex blepharitis.”

Among treated patients in the trial, 56% achieved “complete collarette cure” at day 43, defined as 0 to 2 collarettes per eyelid. 

Potentially even more lucrative for the company is its market in China, where Azamian estimates there are at least 70 million people with Demodex blepharitis. Tarsus has out-licensed TP-03 to LianBio and the program there is trailing “not too far” behind the U.S. development effort. The company is also working on a preservative-free version of the eye drop to align with European regulators and then will pursue approval there. 

If approved, TP-03 would become the bedrock for Tarsus, which Azamian hopes can become “a leading eye care pharmaceutical company.”

The company will now turn to executing on the back-half of its pipeline, with two additional phase 2 trials slated to begin later this year, one testing TP-03 to treat Meibomian gland disease and the other assessing TP-04 as a treatment for rosacea. Tarsus also hopes to release phase 1b data for an oral Lyme disease med and move that therapy into a phase 2 in the second half of the year. 

It's Azamian's intention to let those trials read out before the company considers in-licensing another mid-to-late-stage asset elsewhere to bridge the commercial gap between TP-03 in Demodex blepharitis and one of the current phase 2 treatments. Again, it all centers on wanting to prove the company is not just a one-trick pony by building a larger eye care business. 

“We’re really focused on making TP-03 a big success, that is our key objective as a company,” he said. 

After raising more than $101 million in an IPO in October 2020, Tarsus’ TP-03 push came amid a larger cratering of the biotech market over the last year. The company currently has $175 million in available debt financing to help push both TP-03 onto the market for Demodex blepharitis in addition to funding phase 2 readouts of its other assets. 

Still, Azamian hasn’t lost any sleep awaiting these data, even as the stakes were higher and believes his company is currently undervalued. 

“Where my personal mindset is, is this is a marathon, and it’s something we’re right in the middle of,” he said. “We see a very strong finish to that race as we launch TP-03.”