Bortezomib (brand name Velcade) is a proteasome inhibitor manufactured by Millenium Pharmaceuticals. It is FDA approved for treatment of multiple myeloma and mantle cell lymphoma. It is in clinical trials for several other types of cancers, and some of these trials are open to GIST patients (see below).
Dr. Anette Duensing has done research using GIST cell lines that suggests that proteasome inhibition by bortezomib might be helpful against gastrointestinal stromal tumor (GIST), but this has not yet been verified in lab animals or humans. See our news story about her work.
From the FDA page "The most common side effects with Velcade are nausea, tiredness, diarrhea, constipation, decreased platelet blood count (causing easier bruising and bleeding), fever, vomiting, and decreased appetite. Velcade can cause peripheral neuropathy (loss of sensation in the arms and legs). The most commonly reported serious adverse effects with Velcade include fever, pneumonia, diarrhea, vomiting, dehydration, and nausea."
Velcade is given by intravenous injection.
Quote from the NCI Drug Dictionary page on Velcade:
"A dipeptide boronic acid analogue with antineoplastic activity. Bortezomib reversibly inhibits the 26S proteasome, a large protease complex that degrades ubiquinated proteins. By blocking the targeted proteolysis normally performed by the proteasome, bortezomib disrupts various cell signaling pathways, leading to cell cycle arrest, apoptosis, and inhibition of angiogenesis. Specifically, the agent inhibits nuclear factor (NF)-kappaB, a protein that is constitutively activated in some cancers, thereby interfering with NF-kappaB-mediated cell survival, tumor growth, and angiogenesis. In vivo, bortezomib delays tumor growth and enhances the cytotoxic effects of radiation and chemotherapy."
Links for more information:
FDA page on bortezomib
Information from manufacturer, Millenium Pharmaceuticals: