17-AAG (tanespimycin, KOS-953) and Bortezomib

This phase I trial is studying the side effects and best dose of giving 17-AAG (tanespimycin, or KOS-953) together with bortezomib in treating patients with advanced solid tumors or lymphomas.  GIST patients could enroll if meeting the criteria.

For the trial description link to clinicaltrials.gov

Bortezomib is a proteasome inhibitor already approved by the FDA for treatment of multiple myeloma.  The proteasome is the "recycling center" inside the cell; inhibiting it effectively inactivates proteins that require reformulation prior to re-use by the cell.  Bortezomib has not been studied as an agent for GIST.   Theoretically, there might be anti-cancer synergism by inhibiting both HSP90 and the proteasome in some types of cancer, as both HSP90 and the proteasome function in a linked manner to regulate protein levels in a cancer cell.  The combination might reduce KIT expression further.

Bortezomib is marketed as brand name Velcade.  You can link to the FDA page on bortezomib.

For bortezomoib information at the site of the manufacturer Millenium Pharmaceuticals link here.