Morrisville-based Envisia Therapeutics has raised $4.6 million of a $5.1 million debt offering, according to a regulatory filing. Earlier this month, Envisia reported positive clinical trial results for its experimental glaucoma treatment.

The Envisia treatment, ENV515, is a biodegradable implant that delivers sustained treatment and could last eight months.

In trials, ENV515 showed results comparable to Travatan Z, the once-daily eye drop treatment from Alcon. The possibility that ENV515 would need to be implanted twice a year could make it a preferred treatment.

Envisia is a Liquidia Technologies spinout and raised $25 million from Liquidia investors to develop the glaucoma drug.

The company has grown to 23 employees since the 2013 spinout.

The company reported the debt offering in a filing with the U.S. Securities and Exchange Commission. Here’s the filing: