S0502: A SWOG Phase III Randomized Study of Imatinib, With or Without Bevacizumab, in Patients With Untreated Metastatic or Unresectable Gastrointestinal Stromal Tumors.

LESSONS LEARNED: Despite having significant rationale, S0502 failed to accrue for a number of reasons.Vetting a trial first, with scientific experts and funding agencies, does not guarantee success, especially when dealing with a rare tumor and/or one with an existing highly effective therapy.In the present case, adding an intravenous drug to an oral medication as part of a regimen expected to be continued for many years likely decreased patient (and physician) convenience and, thus, interest in the study. BACKGROUND: Imatinib mesylate, a potent inhibitor of the KIT and PDGFR tyrosine kinases, is highly effective in the treatment of advanced gastrointestinal stromal tumors (GISTs). However, most imatinib-treated tumors eventually become resistant, accounting for a median progression-free survival of 19-23 months. Expression of vascular endothelial growth factor (VEGF) correlates with poor prognosis in GIST; bevacizumab, a monoclonal antibody against VEGF, is effective in a variety of solid tumors. We postulated combination therapy with imatinib plus bevacizumab would benefit patients with advanced GIST, particularly those reliant on VEGFA-dependent angiogenesis. METHODS: Patients with metastatic or surgically unresectable GIST were eligible for this phase III open-label clinical trial, S0502. At registration, patients were randomly assigned to either imatinib 400 mg (standard) or 800 mg (patients with exon 9 KIT mutations), or imatinib plus bevacizumab, 7.5 mg/kg i.v. every 3 weeks. Patients were treated to progression, symptomatic deterioration, unacceptable toxicity, treatment delay greater than 4 weeks, or patient choice to withdraw from the study. The primary objective was to determine whether the addition of bevacizumab to imatinib would improve progression-free survival (PFS) in first-line treatment of incurable GIST. RESULTS: S0502 opened on April 15, 2008. As of fall 2009, only 12 patients from at least 178 eligible SWOG centers plus those participating through Cancer Trials Support Unit had been entered in the study. Despite an aggressive promotion scheme involving the other cooperative groups and a major GIST patient advocacy group, accrual remained slow. The trial was closed on October 1, 2009, having accrued only 2% of the 572 patients planned. No scientific conclusions were forthcoming because of the small number of patients entered in the study. Two patients of the 6 in the combination arm reported grade 3 toxicities, 1 with proteinuria and 1 with fatigue, upper gastrointestinal hemorrhage, and anemia. CONCLUSION: No conclusions may be drawn from this trial and, thus, the combination of imatinib plus bevacizumab cannot be recommended for use.

Phase II trial of gemcitabine as first line chemotherapy in patients with metastatic or unresectable soft tissue sarcoma.

OBJECTIVE: The availability of effective chemotherapy agents or regimens for soft tissue sarcomas (STS) is limited. Response to available first line regimens is generally poor and response to second line regimens is rare. Considering the poor response of STS to available cytotoxic therapy, and the need to adequately evaluate the effectiveness of new agents, first line investigation of promising new agents is justified. Gemcitabine, a relatively new agent, has demonstrated effectiveness in several solid tumors. Limited clinical trials have suggested modest activity in STS. A multi-institutional study of gemcitabine in patients with STS, without prior chemotherapy for metastatic disease, was initiated in the Southwest Oncology Group May 1, 1998 and completed March 15, 1999. MATERIALS AND METHODS: Patients were required to have metastatic or unresectable STS with no prior chemotherapy for metastatic disease. Gastrointestinal leiomyosarcomas and stromal tumors were not eligible. Patients were required to have a performance status of 0-2, measurable disease, adequate renal, hepatic, and hematologic function. The patients were given Gemcitabine 1000 mg/M2 iv over 30 minutes on days 1, 8, and 15, 22, 29, 36, 43, 57, 64, and 71. Dosage reduction was performed for cytopenias and/or other grade 3 or 4 toxicity. RESULTS: Forty-eight patients were registered to the study. The median age was 62 years (range, 30-80) with 21 male and 25 female patients. Two patients were ineligible (1 GI stromal tumor and 1 nerve sheath tumor). Forty-six patients are evaluable for response, toxicity, and survival. There were 2 treatment-related deaths (1 renal failure and 1 hemolytic uremic syndrome). Six additional patients experienced grade 4 toxicity (3 neutropenia, 2 dyspnea, 1 vomiting, and 1 renal failure). Three of the 46 eligible patients had a partial response (7%: 95% confidence interval 1-18%) and 8 patients had stable disease (20%). Nine patients had inadequate assessments to define response. Forty-five patients have died with a median survival of 6 months (95% confidence interval 5-10 months). CONCLUSION: Gemcitabine has minimal activity as a single agent at this dose and schedule in advanced STS. The low response rate does not justify further investigation of gemcitabine as a single agent in STS.