Tracon winds down weeks after world's first injectable PD-L1 inhibitor stumbles in phase 2

Tracon Pharmaceuticals has decided to wind down operations weeks after an injectable immune checkpoint inhibitor that was licensed from China flunked a pivotal trial in a rare cancer.

The biotech gave up on envafolimab after the subcutaneous PD-L1 inhibitor only triggered responses in four out of 82 patients who had already received therapies for their undifferentiated pleomorphic sarcoma or myxofibrosarcoma. At 5%, the response rate was below the 11% the company had been aiming for.

The disappointing results ended Tracon’s plans to submit envafolimab to the FDA for approval as the first injectable immune checkpoint inhibitor, despite the drug having already secured the regulatory green light in China.

At the time, CEO Charles Theuer, M.D., Ph.D., said the company was moving to “immediately reduce cash burn” while seeking out strategic alternatives.

It looks like those options didn’t pan out, and, this morning, the San Diego-based biotech said that following a special meeting of its board of directors, the company has terminated employees and will wind down operations.

As of the end of 2023, the small biotech had 17 full-time employees, according to its annual securities filing.

It’s a dramatic fall for a company that only weeks ago was eyeing the chance to cement its position with the first subcutaneous checkpoint inhibitor approved anywhere in the world. Envafolimab claimed that title in 2021 with a Chinese approval in advanced microsatellite instability-high or mismatch repair-deficient solid tumors regardless of their location in the body. The tumor-agnostic nod was based on results from a pivotal phase 2 trial conducted in China.

Tracon in-licensed the North America rights to envafolimab in December 2019 through an agreement with the drug’s Chinese developers, 3D Medicines and Alphamab Oncology.