Correlation of Long-term Results of Imatinib in Advanced Gastrointestinal Stromal Tumors With Next-Generation Sequencing Results: Analysis of Phase 3 SWOG Intergroup Trial S0033.

IMPORTANCE: After identification of activating mutations of the KIT gene in gastrointestinal stromal tumor (GIST)-the most common sarcomaof the gastrointestinal tract-a phase 2 study demonstrated efficacy of imatinib mesylate in patients with metastatic GIST harboring a KIT exon 11 mutation. Initial results of long-term follow-up have found a survival benefit in this subgroup of patients. OBECTIVE: To assess the long-term survival of patients with GIST who were treated in SWOG study S0033 and to present new molecular data regarding treatment outcomes. DESIGN, SETTING, AND PARTICIPANTS: In this follow-up of randomized clinical trial participants (from December 15, 2000, to September 1, 2001), patients were required to have advanced GIST that was not surgically curable. Postprotocol data collection occurred from August 29, 2011, to July 15, 2015. Using modern sequencing technologies, 20 cases originally classified as having wild-type tumors underwent reanalysis. This intergroup study was coordinated by SWOG, a cooperative group member within the National Clinical Trials Network, with participation by member/affiliate institutions. This follow-up was not planned as part of the initial study. INTERVENTIONS: Patients were randomized to 1 of 2 dose levels of imatinib mesylate, including 400 mg once daily (400 mg/d) vs 400 mg twice daily (800 mg/d), and were treated until disease progression or unacceptable toxic effects of the drug occurred. MAIN OUTCOMES AND MEASURES: The primary end point was overall survival. Updated survival data were correlated with clinical and molecular factors, and patterns of postprotocol therapies were enumerated and described in long-term survivors. RESULTS: Of 695 eligible patients (376 men [54.1%]; 319 women [45.9%]; mean [SD] age, 60.1 [14.0] years), 189 survived 8 years or longer, including 95 in the 400-mg/d dose arm and 94 in the 800-mg/d arm. The 10-year estimate of overall survival was 23% (95% CI, 20%-26%). Among 142 long-term survivors, imatinib was the sole therapy administered in 69 (48.6%), with additional systemic agents administered to 54 patients (38.0%). Resequencing studies of 20 cases originally classified as KIT/PDGFRA wild-type GIST revealed that 17 (85.0%) harbored a pathogenic mutation, most commonly a mutation of a subunit of the succinate dehydrogenase complex. CONCLUSIONS AND RELEVANCE: A subset of patients with metastatic GIST experiences durable, long-term overall survival with imatinib treatment. Although this study provides guidance for management of GIST harboring the most common KIT and PDGFRA mutations, optimal management of other genotypic subtypes remains unclear. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00009906.

Double-Blind Phase III Randomized Trial of the Antiprogestin Agent Mifepristone in the Treatment of Unresectable Meningioma: SWOG S9005.

PURPOSE: Progesterone receptors are expressed in approximately 70% of meningiomas. Mifepristone is an oral antiprogestational agent reported to have modest activity in a phase II study. This multicenter, prospective, randomized, placebo-controlled phase III trial conducted by SWOG was planned to define the role of mifepristone in the treatment of unresectable meningioma. PATIENTS AND METHODS: Eligible patients were randomly assigned to receive either mifepristone or placebo for 2 years unless disease progressed. Patients who were stable or responding to protocol therapy after 2 years had the option to continue with the same blinded therapy. Serial follow-up allowed assessment of efficacy and toxicity. Time to treatment failure and overall survival were ascertained for all randomly assigned patients. On progression, patients receiving placebo could cross over and receive active drug. RESULTS: Among 164 eligible patients, 80 were randomly assigned to mifepristone and 84 to placebo. Twenty-four patients (30%) were able to complete 2 years of mifepristone without disease progression, adverse effects, or other reasons for discontinuation. Twenty-eight patients (33%) in the placebo arm completed the 2-year study. There was no statistical difference between the arms in terms of failure-free or overall survival. CONCLUSION: Long-term administration of mifepristone was well tolerated but had no impact on patients with unresectable meningioma.

Pharmacogenetic Analysis of INT 0144 Trial: Association of Polymorphisms with Survival and Toxicity in Rectal Cancer Patients Treated with 5-FU and Radiation.

PURPOSE: We tested whether 18 polymorphisms in 16 genes (GSTP1, COX2, IL10, EGFR, EGF, FGFR4, CCDN1, VEGFR2, VEGF, CXCR2, IL8, MMP3, ICAM1, ERCC1, RAD51, and XRCC3) would predict disease-free survival (DFS), overall survival (OS), and toxicity in the INT0144 trial, which was designed to investigate different postoperative regimens of 5-fluorouracil (5-FU)-based chemoradiation (CRT) in locally advanced rectal cancers: Arm 1 consisted of bolus 5-FU followed by 5-FU protracted venous infusion (PVI) with radiotherapy; arm 2 was induction and concomitant PVI 5-FU with radiotherapy and arm 3 was induction and concomitant bolus 5-FU with radiotherapy. EXPERIMENTAL DESIGN: DNA from 746 stage II/III rectal patients enrolled in the Southwest Oncology Group (SWOG) S9304 phase III trial was analyzed. Genomic DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tumor tissue. The polymorphisms were analyzed using direct DNA-sequencing or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: GSTP1-Ile105Val (rs1695) was significantly associated with DFS and OS and its effect did not vary by treatment arm. The five-year DFS and OS were 53% and 58%, respectively, for G/G, 66% and 72% for G/A, and 57% and 66% for A/A patients. In arm 2, IL8-251A/A genotype (rs4073) was associated with a lower risk of toxicities (P = 0.04). The VEGFR2 H472Q Q/Q genotype (rs1870377) was associated with a higher risk of grade 3-5 proximal upper gastrointestinal tract (PUGIT) mucositis (P = 0.04) in arm 2. However, in arm 1, this genotype was associated with a lower risk of PUGIT mucositis (P = 0.004). CONCLUSION: rs1695 may be prognostic in patients with rectal cancer treated with adjuvant CRT. rs4073 and rs1870377 may exhibit different associations with toxicity, according to the 5-FU schedule.

A Phase III study of radiation therapy (RT) and O6-benzylguanine + BCNU versus RT and BCNU alone and methylation status in newly diagnosed glioblastoma and gliosarcoma: Southwest Oncology Group (SWOG) study S0001.

AIMS: To determine the efficacy of methylguanine methyltransferase (MGMT) depletion + BCNU [1,3-bis(2-chloroethyl)-1- nitrosourea: carmustine] therapy and the impact of methylation status in adults with glioblastoma multiforme (GBM) and gliosarcoma. METHODS: Methylation analysis was performed on GBM patients with adequate tissue samples. Patients with newly diagnosed GBM or gliosarcoma were eligible for this Phase III open-label clinical trial. At registration, patients were randomized to Arm 1, which consisted of therapy with O(6)-benzylguanine (O(6)-BG) + BCNU 40 mg/m(2) (reduced dose) + radiation therapy (RT) (O6BG + BCNU arm), or Arm 2, which consisted of therapy with BCNU 200 mg/m(2) + RT (BCNU arm). RESULTS: A total of 183 patients with newly diagnosed GBM or gliosarcoma from 42 U.S. institutions were enrolled in this study. Of these, 90 eligible patients received O(6)-BG + BCNU + RT and 89 received BCNU + RT. The trial was halted at the first interim analysis in accordance with the guidelines for stopping the study due to futility (<40 % improvement among patients on the O6BG + BCNU arm). Following adjustment for stratification factors, there was no significant difference in overall survival (OS) or progression-free survival (PFS) between the two groups (one sided p = 0.94 and p = 0.88, respectively). Median OS was 11 [95 % confidence interval (CI) 8-13] months for patients in the O6BG + BCNU arm and 10 (95 % CI 8-12) months for those in the BCNU arm. PFS was 4 months for patients in each arm. Adverse events were reported in both arms, with significantly more grade 4 and 5 events in the experimental arm. CONCLUSIONS: The addition of O(6)-BG to the standard regimen of radiation and BCNU for the treatment patients with newly diagnosed GBM and gliosarcoma did not provide added benefit and in fact caused additional toxicity.

Polymorphisms in folate-metabolizing enzymes and response to 5-fluorouracil among patients with stage II or III rectal cancer (INT-0144; SWOG 9304).

BACKGROUND: Recurrence and toxicity occur commonly among patients with rectal cancer who are treated with 5-fluorouracil (5-FU). The authors hypothesized that genetic variation in folate-metabolizing genes could play a role in interindividual variability. The objective of the current study was to evaluate the associations between genetic variants in folate-metabolizing genes and clinical outcomes among patients with rectal cancer treated with 5-FU. METHODS: The authors investigated 8 functionally significant polymorphisms in 6 genes (methylenetetrahydrofolate reductase [MTHFR] [C677T, A1298C], SLC19A1 [G80A], SHMT1 [C1420T], dihydrofolate reductase [DHFR] [Del19bp], TS 1494del,and TSER) involved in folate metabolism in 745 patients with TNM stage II or III rectal cancer enrolled in a phase 3 adjuvant clinical trial of 3 regimens of 5-FU and radiotherapy (INT-0144 and SWOG 9304). RESULTS: There were no statistically significant associations noted between polymorphisms in any of the genes and overall survival, disease-free survival (DFS), and toxicity in the overall analyses. Nevertheless, there was a trend toward worse DFS among patients with the variant allele of MTHFR C677T compared with wild-type, particularly in treatment arm 2, in which patients with the MTHFR C677T TT genotype had worse overall survival (hazards ratio, 1.76; 95% confidence interval, 1.06-2.93 [P = .03]) and DFS (hazards ratio, 1.84; 95% confidence interval, 1.12-3.03 [P = .02]) compared with those with homozygous wild-type. In addition, there was a trend toward reduced hematological toxicity among patients with variants of SLC19A1 G80A in treatment arm 1 (P for trend, .06) and reduced esophagitis/stomatitis noted among patients with variants of TSER in treatment arm 3 (P for trend, .06). CONCLUSIONS: Genetic variability in folate-metabolizing enzymes was found to be associated only to a limited degree with clinical outcomes among patients with rectal cancer treated with 5-FU.

SWOG 0514: a phase II study of sorafenib in patients with unresectable or metastatic gallbladder carcinoma and cholangiocarcinoma.

OBJECTIVES: Gallbladder and cholangiocarcinomas represent a heterogeneous group of malignant diseases that commonly present at an advanced stage and have limited therapeutic options. Based on the role of the Ras-Raf-Mek-Erk pathway and the VEGF axis in biliary carcinomas, we conducted a phase II study of sorafenib in patients with advanced biliary cancers. METHODS: Eligible patients had no prior therapy for metastatic or unresectable disease. Sorafenib was administered at 400 mg po twice daily continuously. RESULTS: The study was terminated after the first stage of accrual due to failure to meet the primary objective. A confirmed response rate of 0% (0%-11%) was observed. Thirty-nine percent of patients demonstrated stable disease (including 2 with unconfirmed PR). PFS was 3 months (95% CI: 2-4 months) and OS 9 months (95% CI: 4-12 months). The most common grade 3 and 4 toxicities included hand-foot skin reaction (13%), bilirubin elevation (13%), venous thromboembolism (10%), AST/ALT elevation (10%) and elevated alkaline phosphatase (10%). CONCLUSION: While treatment with sorafenib did not result in objective responses, patients with biliary cancers receiving this drug had some therapeutic benefit. Additional studies with sorafenib in combination with chemotherapy or other targeted agents may be warranted.

Phase 2 Southwest Oncology Group-directed intergroup trial (S0505) of sorafenib in advanced soft tissue sarcomas.

BACKGROUND: Patients with advanced soft tissue sarcomas (STS) have limited therapeutic options. Sorafenib (BAY 43-9006) is a multitargeted tyrosine kinase inhibitor of raf, vascular endothelial growth factor receptors 1 (VEGFR1) through 3, platelet-derived growth factor B, fms-like tyrosine kinase 3, and c-kit, and some of these may be relevant in STS. METHODS: The authors tested sorafenib at a dose of 400 mg twice daily in patients with advanced vascular sarcoma (VS), high-grade liposarcomas, and leiomyosarcomas who had received 0 or 1 previous regimens for advanced disease. RESULTS: Fifty-one patients were accrued to the study, and 37 were evaluable for toxicity and response. There were no unexpected side effects and no confirmed responses. The median progression-free survival was 3 months, and the median overall survival was 17 months. Six of 8 patients in the VS cohort had prolonged clinical benefit (stable disease or better), resulting in a median progression-free survival of 5 months compared with 2 to 3 months for the patients who had liposarcoma and leiomyosarcomas. CONCLUSIONS: Sorafenib at the dose and schedule studied did not result in any responses in the VS, liposarcoma, or leiomyosarcoma cohort according to Response Evaluation Criteria in Solid Tumors.

A phase II trial of gemcitabine and capecitabine in patients with unresectable or metastatic gallbladder cancer or cholangiocarcinoma: Southwest Oncology Group study S0202.

PURPOSE: Patients with gallbladder cancer or cholangiocarcinoma were treated with the combination of gemcitabine 1,000 mg/m(2) IV over 100 min on days 1 and 8 and capecitabine 650 mg/m(2) BID PO on days 1-14, administered every 21 days. METHODS: The primary objective of this study was to assess the response rate (confirmed complete and partial responses) of gemcitabine and capecitabine used in advanced/metastatic biliary neoplasms. Secondary objectives included overall survival and toxicities. RESULTS: The study accrued 57 patients from September 2003 to April 2005. Three patients were ineligible, and two others received no treatment. Characteristics of analyzable patients: 35 (67%) cholangiocarcinoma, 17 (33%) gallbladder cancer; PS 0 (18 pts), 1 (26 pts), 2 (8 pts); 26 (50%) men; median age 58.8 years (29.5-85.6). Among 51 patients evaluated for toxicity, 6 experienced grade 4 toxicities. Among 52 patients, there were 7 confirmed partial responses for a confirmed response probability of 13% (95% CI: 6-26%). Six patients had an unconfirmed partial response for an overall response probability of 25% (95% CI: 14-39%). Twelve patients (23%) demonstrated stable disease. The 6-month overall survival was 55% (95% CI: 41-69%), and median survival was 7 months (95% CI: 5-8 months). CONCLUSIONS: The combination of gemcitabine and capecitabine is a well-tolerated regimen with activity in patients with advanced gallbladder cancer and cholangiocarcinoma.

Obesity is an independent prognostic variable in colon cancer survivors.

PURPOSE: Obesity is associated with an increased risk of colon cancer. However, the influence of body mass index (BMI) on the prognosis of colon cancer survivors and its relationship to gender remains unknown. EXPERIMENTAL DESIGN: BMI (kg/m(2)) was categorized in patients with tumor-node-metastasis stage II and III colon carcinomas (n = 4,381) enrolled in seven randomized trials of 5-fluorouracil-based adjuvant chemotherapy. Cox proportional hazards models were used to determine the association of BMI with disease-free survival (DFS) and overall survival (OS). RESULTS: Among colon cancer patients, 868 (20%) were obese (BMI, >or=30 kg/m(2)), of which 606 were class 1 (BMI, 30-34 kg/m(2)) and 262 were class 2,3 (BMI, >or=35 kg/m(2)). Obese versus normal-weight patients were more likely to be younger, have distal tumors, show intact DNA mismatch repair, and have more lymph node metastases (P < 0.017). In a multivariate analysis, BMI was significantly associated with both DFS (P = 0.030) and OS (P = 0.0017). Men with class 2,3 obesity showed reduced OS compared with normal-weight men [hazard ratio, 1.35; 95% confidence interval, 1.02-1.79; P = 0.039]. Women with class I obesity had reduced OS [hazard ratio, 1.24; 95% confidence interval, 1.01-1.53; P = 0.045] compared with normal-weight women. Overweight status was associated with improved OS in men (P = 0.006), and underweight women had significantly worse OS (P = 0.019). BMI was not predictive of therapeutic benefit. CONCLUSIONS: Obesity is an independent prognostic variable in colon cancer survivors and shows gender-related differences. These data suggest that obesity-related biological factors can influence clinical outcome.

Imatinib mesylate in advanced dermatofibrosarcoma protuberans: pooled analysis of two phase II clinical trials.

PURPOSE: Dermatofibrosarcoma protuberans (DFSP) is a dermal sarcoma typically carrying a translocation between chromosomes 17 and 22 that generates functional platelet-derived growth factor B (PDGFB). PATIENTS AND METHODS: Two distinct phase II trials of imatinib (400 to 800 mg daily) in patients with locally advanced or metastatic DFSP were conducted and closed prematurely, one in Europe (European Organisation for Research and Treatment of Cancer [EORTC]) with 14-week progression-free rate as the primary end point and the other in North America (Southwest Oncology Group [SWOG]) with confirmed objective response rate as the primary end point. In the EORTC trial, confirmation of PDGFB rearrangement was required, and surgery was undertaken after 14 weeks if feasible. The SWOG study confirmed t(17;22) after enrollment. RESULTS: Sixteen and eight patients were enrolled onto the EORTC and SWOG trials, respectively. Tumor size ranged from 1.2 to 49 cm. DFSP was located on head/neck, trunk, and limb in seven, 11, and six patients, respectively, and was classic, pigmented, and fibrosarcomatous DFSP in 13, one, and nine patients, respectively. Metastases were present in seven patients (lung involvement was present six patients). Eleven patients (4%) had partial response as best response, and four patients had progressive disease as best response. Median time to progression (TTP) was 1.7 years. Imatinib was stopped in 11 patients because of progression, one patient because of toxicity, and two patients after complete resection of disease. Median overall survival (OS) time has not been reached; 1-year OS rate was 87.5%. CONCLUSION: Imatinib is active in DFSP harboring t(17;22) including fibrosarcomatous DFSP, with objective response rate approaching 50%. Response rates and TTP did not differ between patients taking 400 mg daily versus 400 mg twice a day.

Multiple Histology Phase II Trials.

PURPOSE: Testing agents in cancers with multiple disease subtypes, in which the activity of a new treatment may vary between subtypes, presents statistical and logistical challenges. We propose a flexible phase II strategy which includes both analyses for each histology or stratum and a combined analysis which borrows information from all the patients in the study. Sequential futility analyses are conducted once each subgroup or the overall group reaches a specified minimum accrual. EXPERIMENTAL DESIGN: Examples based on a soft tissue sarcoma phase II trial, which includes multiple histologies and simulation studies, are used to assess the statistical properties of the proposed strategy. RESULTS: The combined analyses in one phase II trial lead to smaller expected sample sizes when the drug is broadly inactive, and to greater statistical power if there is modest activity across multiple strata as compared with conducting several smaller phase II studies. In addition, by retaining the stratum-specific tests, the design allows the identification of subgroups for which the agents are most active. CONCLUSION: To consider phase II testing with multiple biological subtypes, a strategy which combines both the individual subgroup tests and overall combined tests has promising statistical properties. Our results support the appropriate use of statistical borrowing of information in phase II studies in this setting. More broadly, this work fits the paradigm that phase II studies should include as broad a group of patients as scientifically reasonable, but incorporate design considerations for subsets of patients with potentially differing responses to therapy.

Phase II trial of romidepsin (NSC-630176) in previously treated colorectal cancer patients with advanced disease: a Southwest Oncology Group study (S0336).

INTRODUCTION: Patients with metastatic colorectal cancer who progress on standard chemotherapy have limited treatment options. New and effective drugs are needed for these patients. Romidepsin is a histone deacetylase inhibitor that can alter chromatin structure and gene transcription leading to multiple changes in cellular protein production. This may result in cell cycle arrest and tumor growth inhibition. Romidepsin has shown anti-proliferative activity in vitro against multiple mouse and human tumor cell lines and in vivo in human tumor xenograft models. PATIENTS AND METHODS: Patients were required to have pathologically verified, measurable, metastatic or locally advanced colorectal cancer that was surgically unresectable. They must have failed either one or two prior chemotherapy regimens, had performance status of 0-1, adequate bone marrow, renal and hepatic function, and no significant cardiac disease. Patients were treated with romidepsin at a dose of 13 mg/m(2) as a 4-h iv infusion on days 1, 8, and 15 of a 28-day cycle. The study had a two stage design. The primary objective of the study was to determine the confirmed response probability in this group of patients treated with romidepsin. RESULTS: Twenty-eight patients were registered to the study, two of whom were ineligible. One eligible patient refused all treatment and was not analyzed. For the 25 remaining patients, performance status was 0 in 16 patients and 1 in nine patients. Ten patients had received one prior chemotherapy regimen and fifteen 2 prior regimens. Out of the 25 eligible and analyzable patients accrued in the first stage of the protocol, no objective responses were observed and the study was permanently closed. Four patients had stable disease as the best response. Twenty-five patients were assessed for toxicity. No grade 4 or greater toxicities were seen. Fourteen of the 25 patients experienced grade 3 toxicities the most common of which were fatigue or anorexia. CONCLUSION: Romidepsin at this dose and schedule is ineffective in the treatment of patients with metastatic colorectal cancer after prior chemotherapy. Future trials might evaluate combinations of romidepsin with chemotherapeutic or other agents.

Correlation of kinase genotype and clinical outcome in the North American Intergroup Phase III Trial of imatinib mesylate for treatment of advanced gastrointestinal stromal tumor: CALGB 150105 Study by Cancer and Leukemia Group B and Southwest Oncology Group.

PURPOSE: Imatinib mesylate is standard treatment for patients who have advanced gastrointestinal stromal tumor (GIST), but not all patients benefit equally. In previous studies, GIST genotype correlated with treatment outcome and optimal imatinib dosing. PATIENTS AND METHODS: We examined the relationship between kinase genotype and treatment outcome for 428 patients enrolled on the North American phase III study SWOG S0033/CALGB 150105 and treated with either 400 mg or 800 mg daily doses of imatinib. RESULTS: The presence of KIT exon 11-mutant genotype (n = 283) correlated with improved treatment outcome when compared with KIT exon 9-mutant (n = 32) and wild-type (WT; n = 67) genotypes for objective response (complete response [CR]/partial response [PR], 71.7% v 44.4% [P = .007]; and 44.6% [P = .0002], respectively); time to tumor progression (TTP; median 24.7 months v 16.7 and 12.8 months, respectively); and overall survival (OS; median 60.0 months v 38.4 and 49.0 months, respectively). The survival outcomes for patients with exon 9-mutant, exon 11-mutant or WT GIST were not affected by imatinib dose. However, there was evidence of improved response rates for patients with exon 9-mutant tumors treated with imatinib 800 mg versus 400 mg (CR/PR, 67% v 17%; P = .02). Patients who had CD117-negative GIST had similar TTP but inferior OS compared with patients who had CD117-positive disease, which suggests that patients who have CD117-negative GIST may benefit from imatinib treatment. In addition, we identified novel but rare mutations of the KIT extracellular domain (exons 8 and 9). CONCLUSION: We confirmed the favorable impact of KIT exon 11 genotype when compared with KIT exon 9 and wild-type genotype for patients with advanced GIST who are treated with imatinib.

External beam irradiation and the combination of cisplatin and carmustine followed by carmustine alone for the treatment of high-grade glioma: a phase 2 Southwest Oncology Group trial.

BACKGROUND: The poor prognosis reported for patients with high-grade glial neoplasms indicates a need for the development of multimodality therapeutic approaches. The addition of chemotherapy has contributed variably to increased survival. The objective of the current study (Southwest Oncology Group [SWOG] 9016) was to determine whether concurrent radiotherapy and chemotherapy with the combination of carmustine and cisplatin could be given safely in a cooperative group setting. Additional objectives included the estimation of response rate, the rate of disease stabilization, and the probability of 1-year survival. METHODS: SWOG 9016 study included 59 eligible patients with grade III or IV astrocytoma who received radiotherapy concurrently with carmustine/cisplatin chemotherapy. Patients were required to have either measurable or evaluable disease. The therapeutic endpoints were comprised of complete response (CR), partial response (PR), or progressive disease (PD). RESULTS: Six patients achieved a CR (CR rate of 10%; 95% confidence interval [95% CI], 4-21%), 4 achieved a PR (PR rate of 7%; 95% CI, 2-16%), and 2 patients (3%) experienced an unconfirmed response. Twenty-four patients (41%; 95% CI, 28-54%) had stable disease and 10 patients (17%) demonstrated PD. The overall disease stabilization rate (CR + PR + stable disease, excluding unconfirmed response) was 58% (95% CI, 44-70%). CONCLUSIONS: Despite the presence of a cohort of long-term survivors, the results of the current study do not appear to support the additional study or routine use of concurrent cisplatin and carmustine.

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.

A phase II study of cisplatin preceded by a 12-h continuous infusion of concurrent hydroxyurea and cytosine arabinoside (Ara-C) for adult patients with malignant gliomas (Southwest Oncology Group S9149).

Inhibition of DNA excision repair can modulate resistance to cisplatin. Cytosine arabinoside (Ara-C) and hydroxyurea (HU), in combination, inhibit the excision-repair system and removal of platinum-DNA adducts. Marked cytotoxic synergy had been demonstrated in vitro at clinically achievable levels. The three-drug regimen was found to be feasible in clinical pilot studies. A Phase II study in patients with relapsed or progressive anaplastic astrocytoma (AA) or glioblastoma multiforme (GBM) was performed in the Southwest Oncology Group. The primary end point was 6 month survival, historically about 42%. A loading dose of HU 1,260 mg/m2 IV over 1 h was followed by Ara-C 1,200 mg/m2 plus HU 5,040 mg/m2 IV over 12 h, followed by cisplatin 100 mg/m2 IV over 1 h. A total of 76 patients were registered. The GBM stratum registered 56 patients in a two-stage accrual. Among 51 eligible GBM patients, the 6-month survival probability was 41% (95% CI 28-55%), and median overall survival was 5 months (95% CI 4-6 months). The 6-month progression-free survival probability was 25% (95% CI 14-37%), and median progression-free survival was 2 months (95% CI 2-4 months). One patient achieved a partial response (2%, 95% CI 0-10%), 13 patients had stable disease (25%, 95% CI 14-39%). Twenty-two patients progressed, and 14 were not assessable for response. The AA stratum was closed early after 20 patients due to slow accrual. Among 19 eligible patients, the 6-month survival probability was 58% (95% CI 36-80%), and median overall survival was 7 months (95% CI 7-14 months). The 6-month progression-free survival probability was 26% (95% CI 6-46%), and median progression-free survival was 3 months (95% CI 2-5 months). No responses were seen. Six patients (32%) had stable disease (95% CI 13-57%), 11 progressed, and 2 were not assessable for response. Of the 70 patients evaluable for toxicity, two died of infection. Twenty-three patients (33%) experienced Grade 4 toxicities, primarily hematological. Cisplatin combined with HU and Ara-C did not improve the 6 month survival rate in patients with relapsed or progressive AA or GBM. Significantly more hematological toxicity was seen than expected from cisplatin alone. Although benefit might be possible in a more platinum-sensitive tumor type, further clinical trials with this regimen for patients with glioblastoma multiforme or anaplastic astrocytoma are not justified.

Gemcitabine and cisplatin in unresectable malignant mesothelioma of the pleura: a phase II study of the Southwest Oncology Group (SWOG 9810).

PURPOSE: The purpose of this open-label phase II SWOG study was to evaluate the activity of gemcitabine (Gemzar; Eli Lilly, Indiana, USA) and cisplatin combination therapy, in patients with unresectable malignant mesothelioma of the pleura. PATIENTS AND METHODS: Fifty eligible chemotherapy naïve patients with histologically proven malignant mesothelioma of the pleura, and a SWOG performance status 0-2 were enrolled between February 1999 and August 2000. Treatment consisted of gemcitabine 1000mg/m(2) and cisplatin 30mg/m(2) on days 1, 8 and 15 of a 28-day cycle, until progression of disease or two cycles beyond complete response. RESULTS: Using SWOG response criteria, one patient had a confirmed complete response and five patients had a confirmed partial response, for a total response rate of 12% (95% CI 5-24%). All the responses were seen in patients with epithelioid or unspecified histology. Stable disease was seen in 25 patients (50%). The median overall survival was 10 months (95% CI 7-15 months), with a median progression-free survival of 6 months. Sixteen patients experienced Grade 4 toxicity. Twelve of these Grade 4 toxicities were hematologic. There were no treatment-related deaths. CONCLUSIONS: Cisplatin-gemcitabine combination chemotherapy has modest activity with an acceptable toxicity profile, as first line treatment for patients with malignant mesothelioma.

Phase II evaluation of an intensified induction therapy with standard daunomycin and cytarabine followed by high dose cytarabine for adults with previously untreated acute myeloid leukemia: a Southwest Oncology Group study (SWOG-9500).

Induction therapy for acute myeloid leukemia (AML) usually consists of 7 days of cytarabine at 100-200 mg/m(2)/day and an anthracycline. Such combinations produce complete response (CR) rates of 60-80% in patients with de novo AML. On the basis of a previous report, suggesting a higher CR rate using a regimen of standard daunomycin and cytarabine followed by 3 days of high-dose cytarabine (HDAC), 101 eligible patients received this regimen in a phase II trial. Sixty patients [59%, 95% confidence interval (CI) 49-69%] achieved a CR, and 10 patients died of infection during induction. Although cytogenetic risk group affected overall survival (P = 0.0016) and relapse-free survival (P = 0.0043), it had no impact on CR rate (P = 0.63). Patients received postremission therapy with repetitive courses of alternate day high-dose cytarabine; this was associated with considerable toxicity and the majority of patients could not receive all of the scheduled postremission therapy. The estimated median survival was 23 months (95% CI 15-34 months), and the estimated probability of surviving 5 years was 34% (95% CI 24-43%). The results of this intensive induction regimen were similar to that seen in previous trials and were not as promising as reported in the previous pilot study.

Phase II study of erlotinib in patients with malignant pleural mesothelioma: a Southwest Oncology Group Study.

PURPOSE: Malignant pleural mesothelioma (MPM) expresses high levels of epidermal growth factor receptor (EGFR), and preclinical studies have identified antitumor activity of EGFR tyrosine kinase inhibitors (TKIs) in MPM. We conducted a phase II trial of the EGFR TKI erlotinib in previously untreated patients with MPM. PATIENTS AND METHODS: Patients with measurable and nonmeasurable disease were treated with erlotinib 150 mg/d on days 1 through 28 of each 28-day dosing cycle. Archived patient tumors were analyzed for immunohistochemical expression of EGFR, phospho-EGFR, human epidermal growth factor receptor 2 (HER2), phospho-extracellular signal-regulated kinase (ERK), and phosphatase and tensin homolog (PTEN) and phosphorylation of members of the phosphatidylinositol 3-kinase/Akt signaling pathway. RESULTS: Sixty-three patients were treated on the study. EGFR was highly expressed in 75% of patient tumors, as was phospho-ERK (82%), phospho-Akt (84%), phospho-mammalian target of rapamycin (74%), and phospho-forkhead (74%). HER2 was rarely expressed, and loss of PTEN was rare. For 33 patients with measurable disease, there were no objective responses; 14 patients (42%) had stable disease, 15 patients (45%) had disease progression, and four patients had inadequate assessments to determine response. Toxicities were mainly constitutional (51%), dermatologic (82%), and GI (52%); there was one death on trial, which was related to dyspnea. Median overall survival time was 10 months; 1-year survival rate was 43%; and median progression-free survival time was 2 months. CONCLUSION: Single-agent erlotinib was not effective in MPM, despite high expression of EGFR. Activation of the ERK and phosphatidylinositol 3-kinase/Akt downstream pathways are possible resistance mechanisms to EGFR TKI. The activated phosphatidylinositol 3-kinase/Akt pathway is a potential therapeutic target for MPM.

Adjuvant therapy of osteosarcoma--A Phase II trial: Southwest Oncology Group study 9139.

BACKGROUND: The objective of this study was to estimate the time to treatment failure and survival rate of the three-drug combination of doxorubicin, cisplatin, and ifosfamide as primary and postoperative, adjunctive treatment for teenagers and adults with osteosarcoma (OS). METHODS: Sixty-three eligible patients with nonmetastatic OS of the extremities were registered from 24 institutions from February, 1992 through December, 1996. Chemotherapy was comprised of doxorubicin at a dose of 75 mg/m2 and cisplatin at a dose of 120 mg/m2, alternating with doxorubicin at a dose of 50 mg/m2 and ifosfamide at a dose of 8 g/m2. Four cycles were given prior to surgical resection, and four cycles were given after surgery. Outcome measures included the time to treatment failure, overall survival, toxicity, and centralized assessment of tumor necrosis. RESULTS: Thirty-one of 63 eligible patients died, for a 5-year overall survival rate of 58% (95% confidence interval [95% CI], 46-71%). The median time to treatment failure was 19 months (95% CI, 12-41 months). A good pathologic response (> or = 90% necrosis) to neoadjuvant chemotherapy was observed in 48% of patients who underwent surgery. There was no correlation noted between response to neoadjuvant chemotherapy and patient outcome. Grade 4 hematologic toxicities were frequent (89%), although serious nonhematologic toxicities other than nausea and emesis were uncommon. CONCLUSIONS: The regimen and schedule used in the current study did not improve outcomes compared with prior trials of doxorubicin and cisplatin alone. New, more effective drugs are needed for the treatment of patients with OS. The identification and utilization of molecular markers to predict outcome and response to therapy would facilitate clinical management, limiting exposure to toxic therapies for patients with favorable molecular profiles and identifying those patients who may fail with current approaches as candidates for clinical trials.