Tracon Pharmaceuticals Inc.'s cancer drug TRC105 combined with Pfizer Inc.'s Inlyta failed to prolong the time that kidney cancer patients lived without their disease progressing in a mid-stage study.

San Diego-based Tracon reported results from a phase 2 clinical trial named Traxar on Dec. 21. The study compared a combination of TRC105 and Inlyta, or axitinib, with just Inlyta in 150 patients with advanced or metastatic renal cell carcinoma.

Renal cell carcinoma is a type of kidney cancer that starts in the linings of the small tubes that transport urine.

The company said it will end the study following its failure but will present further data and analysis at an upcoming conference.

Tracon President and CEO Charles Theuer said the team is disappointed with the results of Traxar, but the data from the study will support the broader TRC105 program. Specifically, possible biomarkers studied during the Traxar trial could provide clues to single out patients who might respond to the therapy, which could aid the other studies featuring TRC105, Theuer said.

The company remains focused on interim analysis of a separate phase 3 trial for TRC105, which is testing the drug's effectiveness combined with Novartis AG's Votrient in angiosarcoma, a cancer of the inner lining of blood vessels. Data from that trial is due in the first quarter of 2019, Theuer said.

Tracon's TRC105 helps with the formation process of new blood vessels. Besides the angiosarcoma trial, the therapy is also being studied in several other phase 2 trials in combination with certain inhibitors.

The drug has secured orphan designation for treating soft tissue sarcoma in both the U.S. and EU.

Last month, another one of Tracon's cancer drugs, TRC102, combined with Merck & Co. Inc.'s chemotherapy Temodar failed to shrink a type of aggressive brain tumor in a mid-stage study.

Tracon's shares tumbled more than 27% to 73 cents as of 10:32 a.m. ET.