George D. Demetri

Kinase Mutations and Imatinib Response in Patients With Metastatic Gastrointestinal Stromal Tumor

PURPOSE Most gastrointestinal stromal tumors (GISTs) express constitutively activated mutant isoforms of KIT or kinase platelet-derived growth factor receptor alpha (PDGFRA) that are potential therapeutic targets for imatinib mesylate. The relationship between mutations in these kinases and clinical response to imatinib was examined in a group of patients with advanced GIST. PATIENTS AND METHODS GISTs from 127 patients enrolled onto a phase II clinical study of imatinib were examined for mutations of KIT or PDGFRA. Mutation types were correlated with clinical outcome. RESULTS Activating mutations of KIT or PDGFRA were found in 112 (88.2%) and six (4.7%) GISTs, respectively. Most KIT mutations involved exon 9 (n = 23) or exon 11 (n = 85). All KIT mutant isoforms, but only a subset of PDGFRA mutant isoforms, were sensitive to imatinib, in vitro. In patients with GISTs harboring exon 11 KIT mutations, the partial response rate (PR) was 83.5%, whereas patients with tumors containing an exon 9 KIT mutation or no detectable mutation of KIT or PDGFRA had PR rates of 47.8% (P =.0006) and 0.0% (P <.0001), respectively. Patients whose tumors contained exon 11 KIT mutations had a longer event-free and overall survival than those whose tumors expressed either exon 9 KIT mutations or had no detectable kinase mutation. CONCLUSION Activating mutations of KIT or PDGFRA are found in the vast majority of GISTs, and the mutational status of these oncoproteins is predictive of clinical response to imatinib. PDGFRA mutations can explain response and sensitivity to imatinib in some GISTs lacking KIT mutations.

Efficacy and safety of sunitinib in patients with advanced gastrointestinal stromal tumour after failure of imatinib: a randomised controlled trial

BACKGROUND No effective therapeutic options for patients with unresectable imatinib-resistant gastrointestinal stromal tumour are available. We did a randomised, double-blind, placebo-controlled, multicentre, international trial to assess tolerability and anticancer efficacy of sunitinib, a multitargeted tyrosine kinase inhibitor, in patients with advanced gastrointestinal stromal tumour who were resistant to or intolerant of previous treatment with imatinib. METHODS Blinded sunitinib or placebo was given orally once daily at a 50-mg starting dose in 6-week cycles with 4 weeks on and 2 weeks off treatment. The primary endpoint was time to tumour progression. Intention-to-treat, modified intention-to-treat, and per-protocol analyses were done. This study is registered at ClinicalTrials.gov, number NCT00075218. FINDINGS 312 patients were randomised in a 2:1 ratio to receive sunitinib (n=207) or placebo (n=105); the trial was unblinded early when a planned interim analysis showed significantly longer time to tumour progression with sunitinib. Median time to tumour progression was 27.3 weeks (95% CI 16.0-32.1) in patients receiving sunitinib and 6.4 weeks (4.4-10.0) in those on placebo (hazard ratio 0.33; p<0.0001). Therapy was reasonably well tolerated; the most common treatment-related adverse events were fatigue, diarrhoea, skin discolouration, and nausea. INTERPRETATION We noted significant clinical benefit, including disease control and superior survival, with sunitinib compared with placebo in patients with advanced gastrointestinal stromal tumour after failure and discontinuation of imatinab. Tolerability was acceptable.

2006 Update of Recommendations for the Use of White Blood Cell Growth Factors: An Evidence-Based Clinical Practice Guideline

PURPOSE To update the 2000 American Society of Clinical Oncology guideline on the use of hematopoietic colony-stimulating factors (CSF). UPDATE METHODOLOGY The Update Committee completed a review and analysis of pertinent data published from 1999 through September 2005. Guided by the 1996 ASCO clinical outcomes criteria, the Update Committee formulated recommendations based on improvements in survival, quality of life, toxicity reduction and cost-effectiveness. RECOMMENDATIONS The 2005 Update Committee agreed unanimously that reduction in febrile neutropenia (FN) is an important clinical outcome that justifies the use of CSFs, regardless of impact on other factors, when the risk of FN is approximately 20% and no other equally effective regimen that does not require CSFs is available. Primary prophylaxis is recommended for the prevention of FN in patients who are at high risk based on age, medical history, disease characteristics, and myelotoxicity of the chemotherapy regimen. CSF use allows a modest to moderate increase in dose-density and/or dose-intensity of chemotherapy regimens. Dose-dense regimens should only be used within an appropriately designed clinical trial or if supported by convincing efficacy data. Prophylactic CSF for patients with diffuse aggressive lymphoma aged 65 years and older treated with curative chemotherapy (CHOP or more aggressive regimens) should be given to reduce the incidence of FN and infections. Current recommendations for the management of patients exposed to lethal doses of total body radiotherapy, but not doses high enough to lead to certain death due to injury to other organs, includes the prompt administration of CSF or pegylated G-CSF.

Improved Outcomes From Adding Sequential Paclitaxel but Not From Escalating Doxorubicin Dose in an Adjuvant Chemotherapy Regimen for Patients With Node-Positive Primary Breast Cancer

PURPOSE This study was designed to determine whether increasing the dose of doxorubicin in or adding paclitaxel to a standard adjuvant chemotherapy regimen for breast cancer patients would prolong time to recurrence and survival. PATIENTS AND METHODS After surgical treatment, 3,121 women with operable breast cancer and involved lymph nodes were randomly assigned to receive a combination of cyclophosphamide (C), 600 mg/m(2), with one of three doses of doxorubicin (A), 60, 75, or 90 mg/m(2), for four cycles followed by either no further therapy or four cycles of paclitaxel at 175 mg/m(2). Tamoxifen was given to 94% of patients with hormone receptor-positive tumors. RESULTS There was no evidence of a doxorubicin dose effect. At 5 years, disease-free survival was 69%, 66%, and 67% for patients randomly assigned to 60, 75, and 90 mg/m(2), respectively. The hazard reductions from adding paclitaxel to CA were 17% for recurrence (adjusted Wald chi(2) P =.0023; unadjusted Wilcoxon P =.0011) and 18% for death (adjusted P =.0064; unadjusted P =.0098). At 5 years, the disease-free survival (+/- SE) was 65% (+/- 1) and 70% (+/- 1), and overall survival was 77% (+/- 1) and 80% (+/- 1) after CA alone or CA plus paclitaxel, respectively. The effects of adding paclitaxel were not significantly different in subsets defined by the protocol, but in an unplanned subset analysis, the hazard ratio of CA plus paclitaxel versus CA alone was 0.72 (95% confidence interval, 0.59 to 0.86) for those with estrogen receptor-negative tumors and only 0.91 (95% confidence interval, 0.78 to 1.07) for patients with estrogen receptor-positive tumors, almost all of whom received adjuvant tamoxifen. The additional toxicity from adding four cycles of paclitaxel was generally modest. CONCLUSION The addition of four cycles of paclitaxel after the completion of a standard course of CA improves the disease-free and overall survival of patients with early breast cancer.

Adjuvant imatinib mesylate after resection of localised, primary gastrointestinal stromal tumour: a randomised, double-blind, placebo-controlled trial

BACKGROUND Gastrointestinal stromal tumour is the most common sarcoma of the intestinal tract. Imatinib mesylate is a small molecule that inhibits activation of the KIT and platelet-derived growth factor receptor alpha proteins, and is effective in first-line treatment of metastatic gastrointestinal stromal tumour. We postulated that adjuvant treatment with imatinib would improve recurrence-free survival compared with placebo after resection of localised, primary gastrointestinal stromal tumour. METHODS We undertook a randomised phase III, double-blind, placebo-controlled, multicentre trial. Eligible patients had complete gross resection of a primary gastrointestinal stromal tumour at least 3 cm in size and positive for the KIT protein by immunohistochemistry. Patients were randomly assigned, by a stratified biased coin design, to imatinib 400 mg (n=359) or to placebo (n=354) daily for 1 year after surgical resection. Patients and investigators were blinded to the treatment group. Patients assigned to placebo were eligible to crossover to imatinib treatment in the event of tumour recurrence. The primary endpoint was recurrence-free survival, and analysis was by intention to treat. Accrual was stopped early because the trial results crossed the interim analysis efficacy boundary for recurrence-free survival. This study is registered with ClinicalTrials.gov, number NCT00041197. FINDINGS All randomised patients were included in the analysis. At median follow-up of 19.7 months (minimum-maximum 0-56.4), 30 (8%) patients in the imatinib group and 70 (20%) in the placebo group had had tumour recurrence or had died. Imatinib significantly improved recurrence-free survival compared with placebo (98% [95% CI 96-100] vs 83% [78-88] at 1 year; hazard ratio [HR] 0.35 [0.22-0.53]; one-sided p<0.0001). Adjuvant imatinib was well tolerated, with the most common serious events being dermatitis (11 [3%] vs 0), abdominal pain (12 [3%] vs six [1%]), and diarrhoea (ten [2%] vs five [1%]) in the imatinib group and hyperglycaemia (two [<1%] vs seven [2%]) in the placebo group. INTERPRETATION Adjuvant imatinib therapy is safe and seems to improve recurrence-free survival compared with placebo after the resection of primary gastrointestinal stromal tumour. FUNDING US National Institutes of Health and Novartis Pharmaceuticals.

Pazopanib for metastatic soft-tissue sarcoma (PALETTE): a randomised, double-blind, placebo-controlled phase 3 trial.

BACKGROUND Pazopanib, a multitargeted tyrosine kinase inhibitor, has single-agent activity in patients with advanced non-adipocytic soft-tissue sarcoma. We investigated the effect of pazopanib on progression-free survival in patients with metastatic non-adipocytic soft-tissue sarcoma after failure of standard chemotherapy. METHODS This phase 3 study was done in 72 institutions, across 13 countries. Patients with angiogenesis inhibitor-naive, metastatic soft-tissue sarcoma, progressing despite previous standard chemotherapy, were randomly assigned by an interactive voice randomisation system in a 2:1 ratio in permuted blocks (with block sizes of six) to receive either pazopanib 800 mg once daily or placebo, with no subsequent cross-over. Patients, investigators who gave the treatment, those assessing outcomes, and those who did the analysis were masked to the allocation. The primary endpoint was progression-free survival. Efficacy analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00753688. FINDINGS 372 patients were registered and 369 were randomly assigned to receive pazopanib (n=246) or placebo (n=123). Median progression-free survival was 4·6 months (95% CI 3·7-4·8) for pazopanib compared with 1·6 months (0·9-1·8) for placebo (hazard ratio [HR] 0·31, 95% CI 0·24-0·40; p<0·0001). Overall survival was 12·5 months (10·6-14·8) with pazopanib versus 10·7 months (8·7-12·8) with placebo (HR 0·86, 0·67-1·11; p=0·25). The most common adverse events were fatigue (60 in the placebo group [49%] vs 155 in the pazopanib group [65%]), diarrhoea (20 [16%] vs 138 [58%]), nausea (34 [28%] vs 129 [54%]), weight loss (25 [20%] vs 115 [48%]), and hypertension (8 [7%] vs 99 [41%]). The median relative dose intensity was 100% for placebo and 96% for pazopanib. INTERPRETATION Pazopanib is a new treatment option for patients with metastatic non-adipocytic soft-tissue sarcoma after previous chemotherapy. FUNDING GlaxoSmithKline.

Cardiotoxicity associated with tyrosine kinase inhibitor sunitinib

BACKGROUND Sunitinib, a multitargeted tyrosine-kinase inhibitor, which is approved by both US and European Commission regulatory agencies for clinical use, extends survival of patients with metastatic renal-cell carcinoma and gastrointestinal stromal tumours, but concerns have arisen about its cardiac safety. We therefore assessed the cardiovascular risk associated with sunitinib in patients with metastatic gastrointestinal stromal tumours. METHODS We retrospectively reviewed all cardiovascular events in 75 patients with imatinib-resistant, metastatic, gastrointestinal stromal tumours who had been enrolled in a phase I/II trial investigating the efficacy of sunitinib. The composite cardiovascular endpoint was cardiac death, myocardial infarction, and congestive heart failure. We also examined sunitinibs effects on left ventricular ejection fraction (LVEF) and blood pressure. We investigated potential mechanisms of sunitinib-associated cardiac effects by studies in isolated rat cardiomyocytes and in mice. FINDINGS Eight of 75 (11%) patients given repeating cycles of sunitinib in the phase I/II trial had a cardiovascular event, with congestive heart failure recorded in six of 75 (8%). Ten of 36 (28%) patients treated at the approved sunitinib dose had absolute LVEF reductions in ejection fraction (EF) of at least 10%, and seven of 36 (19%) had LVEF reductions of 15 EF% or more. Sunitinib induced increases in mean systolic and diastolic blood pressure, and 35 of 75 (47%) individuals developed hypertension (>150/100 mm Hg). Congestive heart failure and left ventricular dysfunction generally responded to sunitinib being withheld and institution of medical management. Sunitinib caused mitochondrial injury and cardiomyocyte apoptosis in mice and in cultured rat cardiomyocytes. INTERPRETATION Left ventricular dysfunction might be due, in part, to direct cardiomyocyte toxicity, exacerbated by hypertension. Patients treated with sunitinib should be closely monitored for hypertension and LVEF reduction, especially those with a history of coronary artery disease or cardiac risk factors.

Quality-of-life benefit in chemotherapy patients treated with epoetin alfa is independent of disease response or tumor type: results from a prospective community oncology study. Procrit Study Group.

PURPOSE To evaluate prospectively the effectiveness of epoetin alfa as an adjunct to chemotherapy in patients with cancer based on changes in quality-of-life parameters and hemoglobin levels, and to correlate these changes with antitumor response. PATIENTS AND METHODS Two thousand three hundred seventy patients with nonmyeloid malignancies who received chemotherapy were enrolled onto this study from 621 US community-based practices. Patients received epoetin alfa 10,000 U three times weekly, which could be increased to 20,000 U three times weekly depending on the hemoglobin response at 4 weeks. Treatment continued for a maximum of 16 weeks in patients who showed evidence of hematologic response. RESULTS Two thousand two hundred eighty-nine patients (97%) were eligible for efficacy analyses. Epoetin alfa therapy was associated with improved quality-of-life parameters; these improvements correlated significantly with hemoglobin levels and were independent of tumor response. Provider-reported Karnofsky performance scores did not correlate with the improved quality-of-life changes. Epoetin alfa therapy was also associated with a significant increase in hemoglobin levels and decrease in transfusion use. Tumor type, chemotherapy agent/regimen, prior chemotherapy, baseline hemoglobin level, and baseline erythropoietin level were not predictive of a positive response to treatment. Epoetin alfa was well tolerated. CONCLUSION Epoetin alfa appears to have a beneficial impact on patient-reported functional capacity and quality of life in patients with cancer who received chemotherapy independent of tumor response. Concordantly, epoetin alfa appeared to increase hemoglobin levels and decrease transfusion use. Patients responded across all tumor types. The results suggest that epoetin alfa effectively improves functional outcomes in patients with cancer who receive chemotherapy.

Phase III Randomized, Intergroup Trial Assessing Imatinib Mesylate At Two Dose Levels in Patients With Unresectable or Metastatic Gastrointestinal Stromal Tumors Expressing the Kit Receptor Tyrosine Kinase : S0033

PURPOSE To assess potential differences in progression-free or overall survival when imatinib mesylate is administered to patients with incurable gastrointestinal stromal tumors (GIST) at a standard dose (400 mg daily) versus a high dose (400 mg twice daily). PATIENTS AND METHODS Patients with metastatic or surgically unresectable GIST were eligible for this phase III open-label clinical trial. At registration, patients were randomly assigned to either standard or high-dose imatinib, with close interval follow-up. If objective progression occurred by Response Evaluation Criteria in Solid Tumors, patients on the standard-dose arm could reregister to the trial and receive the high-dose imatinib regimen. RESULTS Seven hundred forty-six patients with advanced GIST from 148 centers across the United States and Canada were enrolled onto this trial in 9 months. With a median follow-up of 4.5 years, median progression-free survival was 18 months for patients on the standard-dose arm, and 20 months for those receiving high-dose imatinib. Median overall survival was 55 and 51 months, respectively. There were no statistically significant differences in objective response rates, progression-free survival, or overall survival. After progression on standard-dose imatinib, 33% of patients who crossed over to the high-dose imatinib regimen achieved either an objective response or stable disease. There were more grade 3, 4, and 5 toxicities noted on the high-dose imatinib arm. CONCLUSION This trial confirms the effectiveness of imatinib as primary systemic therapy for patients with incurable GIST but did not show any advantage to higher dose treatment. It appears reasonable to initiate therapy with 400 mg daily and to consider dose escalation on progression of disease.

Long-Term Results From a Randomized Phase II Trial of Standard- Versus Higher-Dose Imatinib Mesylate for Patients With Unresectable or Metastatic Gastrointestinal Stromal Tumors Expressing KIT

PURPOSE The outcome of patients diagnosed with advanced gastrointestinal stromal tumor (GIST) and treated long-term with imatinib mesylate is unknown. A previous report of a randomized phase II trial of imatinib mesylate in patients with incurable GIST detailed high response rates at both the 400 and the 600 mg/d dose levels. We conducted a long-term analysis of patients treated on the trial, including patients followed during an extension phase, to evaluate survival, patterns of failure, and potential prognostic factors, including tumor mutational status. PATIENTS AND METHODS Patients with advanced GIST were enrolled onto an open-label, multicenter trial and were randomly assigned (1:1) to receive imatinib 400 versus 600 mg/d. Data were prospectively collected on KIT mutational status, total tumor area, and other potential prognostic factors. Patients were followed for a median of 63 months. RESULTS One hundred forty-seven patients were enrolled: 73 were in arm A (imatinib 400 mg/d), and 74 were in arm B (imatinib 600 mg/d). Response rates, median progression-free survival, and median overall survival were essentially identical on both arms, and median survival was 57 months for all patients. Forty-one patients overall (28%) remained on the drug long-term. Female sex, the presence of an exon 11 mutation, and normal albumin and neutrophil levels were independently associated with better survival. CONCLUSION Nearly 50% of patients with advanced GIST who were treated with imatinib mesylate survived for more than 5 years, regardless of a 400 or 600 mg/d starting dose.