PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biologic therapy (e.g., interferons, interleukins) Chemotherapy: No prior chemotherapy Endocrine therapy: No concurrent systemic steroids Radiotherapy: No prior radiotherapy Surgery: At least 30 days since prior surgery Decompressive surgery and endoscopic stenting (including expandable wire stents) allowed to relieve symptoms of disease Other: At least 30 days since prior investigational therapy Palliative care to relieve symptoms of disease allowed, including pain management and celiac block by endoscopic ultrasonography or percutaneously