GI-6301 / Brachyury


The GI-6301 Tarmogen is designed to target cancers expressing the brachyury protein, which plays a role in metastatic progression of certain cancers and the initiation of chordoma. GI-6301 has been exclusively licensed to Celgene.

A variety of cancers express the brachyury protein, including lung, breast, colon, bladder, kidney, ovary, uterus and prostate. Brachyury is also expressed in all chordomas, a rare and difficult-to-treat bone tumor. The frequency of brachyury expression increases with stage of disease. In lung cancer, approximately 60% of later stage lung cancer biopsies showed expression of brachyury, compared to approximately 40% of earlier stage lung cancers.

In July 2013, Celgene exercised its option to obtain an exclusive license to the GI-6300 program, including GI-6301. We anticipate that GI-6301 will be investigated in chordoma, and other brachyury-expressing cancers.

Clinical Program

Phase 1 Study

In February 2012, in collaboration with the National Cancer Institute (NCI), we initiated a Phase 1 clinical trial with GI-6301 in subjects with metastatic cancers who have failed previous therapy or have no further therapeutic options.

  • The trial is an open label, single agent, sequential dose escalation trial, with three to six subjects per dose group. Three dose levels were planned under the original protocol: 4YU, 16YU and 40YU. Ten additional subjects were enrolled in an expansion group at the 40YU dose. The protocol was amended in November 2013 to add a fourth, 80YU dose group of ten subjects to the trial.
  • The endpoints of this study are safety, tolerability, brachyury-specific immune responses and clinical benefit.

Initial data from this study demonstrates that GI-6301 is generally well tolerated at all dose levels.