O6-methylguanine-DNA methyltransferase (MGMT) immunohistochemistry as a predictor of resistance to temozolomide in primary CNS lymphoma.

Temozolomide, an alkylating agent, has shown promise in treating primary central nervous system lymphoma (PCNSL). The enzyme O(6)-methylguanine-DNA methyltransferase (MGMT) repairs alkylating damage, such as that induced by temozolomide. We hypothesized that MGMT immunohistochemistry would predict resistance to temozolomide in PCNSL. A retrospective study of newly-diagnosed and recurrent PCNSL patients treated at our institution was conducted to study the predictive value of MGMT immunohistochemistry for response to temozolomide. 20 patients who were treated with temozolomide as a single agent were identified during the study time period. 6/20 patients demonstrated a response, corresponding to an objective response rate of 30 % (95 % CI 8-52). Five patients with low MGMT level (<30 %) showed a response to temozolomide. Only one of 10 patients (10 %) with high MGMT level (≥30 %) exhibited a response to temozolomide. Small sample numbers precluded formal statistical comparisons. Two patients with complete response remain alive without progressive disease 6.7 and 7.2 years after temozolomide initiation. Immunohistochemistry can be performed on small biopsies to selectively assess MGMT status in tumor versus surrounding inflammation. MGMT analysis by immunohistochemistry may predict response to temozolomide in PCNSL and should be prospectively investigated.

Phase II trial of Gliadel plus O6-benzylguanine in adults with recurrent glioblastoma multiforme.

PURPOSE: This phase II trial was designed to define the efficacy of Gliadel wafers in combination with an infusion of O6-benzylguanine (O6-BG) that suppresses tumor O6-alkylguanine-DNA alkyltransferase (AGT) levels in patients with recurrent glioblastoma multiforme for 5 days and to evaluate the safety of this combination therapy. EXPERIMENTAL DESIGN: This was a phase II, open-label, single center trial. On gross total resection of the tumor, up to eight Gliadel wafers were implanted. Bolus infusion of O6-BG was administered at 120 mg/m2 over 1 hour on days 1, 3, and 5, along with a continuous infusion at 30 mg/m2/d. The primary end points were 6-month overall survival (OS) and safety, and the secondary end points were 1-year, 2-year, and median OS. RESULTS: Fifty-two patients were accrued. The 6-month OS was 82% [95% confidence interval (95% CI), 72-93%]. The 1- and 2-year OS rates were 47% (95% CI, 35-63%) and 10% (95% CI, 3-32%), respectively. The median OS was 50.3 weeks (95% CI, 36.1-69.4 weeks). Treatment-related toxicity with this drug combination included grade 3 hydrocephalus (9.6%), grade 3 cerebrospinal fluid (CSF) leak (19.2%), and grade 3 CSF/brain infection (13.4%). CONCLUSION: The efficacy of implanted Gliadel wafers may be improved with the addition of O6-BG. Although systemically administered O6-BG can be coadministered with Gliadel wafers safely, it may increase the risk of hydrocephalus, CSF leak, and CSF/brain infection. Future trials are required to verify that inhibition of tumor AGT levels by O6-BG results in increased efficacy of Gliadel wafers without added toxicity.

Phase I trial of temozolomide plus O6-benzylguanine 5-day regimen with recurrent malignant glioma.

This phase I clinical trial conducted with patients who had recurrent or progressive malignant glioma (MG) was designed to determine the maximum tolerated dose (MTD) and toxicity of three different 5-day dosing regimens of temozolomide (TMZ) in combination with O(6)-benzylguanine (O(6)-BG). Both TMZ and O(6)-BG were administered on days 1-5 of a 28-day treatment cycle. A bolus infusion of O(6)-BG was administered at 120 mg/m(2) over 1 h on days 1, 3, and 5, along with a continuous infusion of O(6)-BG at 30 mg/m(2)/day. TMZ was administered at the end of the first bolus infusion of O(6)-BG and then every 24 h for 5 days during the continuous infusion of O(6)-BG. Patients were accrued to one of three 5-day dosing regimens of TMZ. Twenty-nine patients were enrolled into this study. The dose-limiting toxicities (DLTs) were grade 4 neutropenia, leukopenia, and thrombocytopenia. The MTD for TMZ for the three different 5-day dosing schedules was determined as follows: schedule 1, 200 mg/m(2) on day 1 and 50 mg/m(2)/day on days 2-5; schedule 2, 50 mg/m(2)/day on days 1-5; and schedule 3, 50 mg/m(2)/day on days 1-5 while receiving pegfilgrastim. Thus, the 5-day TMZ dosing schedule that maximized the total dose of TMZ when combined with O(6)-BG was schedule 1. This study provides the foundation for a phase II trial of O(6)-BG in combination with a 5-day dosing schedule of TMZ in TMZ-resistant MG.

Phase II trial of temozolomide (TMZ) plus irinotecan (CPT-11) in adults with newly diagnosed glioblastoma multiforme before radiotherapy.

This phase II trial evaluated efficacy and safety of temozolomide (TMZ) in combination with irinotecan (CPT-11) before radiotherapy in patients with newly diagnosed glioblastoma multiforme (GBM). Prior to radiotherapy, patients were treated with a maximum of three 6-week cycles of TMZ and CPT-11. Patients received TMZ at a dose of 200 mg/m(2)/day on days 1-5 and CPT-11 on days 1, 8, 22, and 29, with a dose adjustment for enzyme-inducing antiepileptic drug use. The primary end point was objective response rate (ORR). Secondary end points included progression-free survival (PFS), overall survival (OS), safety, and tumor O(6)-methylguanine-DNA methyltransferase (MGMT) expression. Of the 42 patients treated, 8 (19%) patients achieved a partial response. Median PFS and median OS were 3.1 and 13.8 months, respectively. Grade 3 or 4 AEs were documented in 36% of patients, most of which were hematologic (29%). Twenty-four percent of patients had grade 3 or 4 non-hematologic AEs, with gastrointestinal AEs being the most common (12%) Two patients died, one of intracranial hemorrhage and one of treatment-related renal failure. Low MGMT expression, compared with high MGMT expression, showed no significant difference in ORR (25 vs. 8%), median PFS (14 vs. 5 months) or OS (21 vs. 15 months). Although TMZ plus CPT-11 is at least comparable in efficacy to TMZ alone, this combination appears more toxic and poorly tolerated. The lack of correlation of activity with MGMT expression is intriguing, but needs further evaluation in subsequent trials.

Mismatch repair deficiency does not mediate clinical resistance to temozolomide in malignant glioma.

PURPOSE: A major mechanism of resistance to methylating agents, including temozolomide, is the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT). Preclinical data indicates that defective DNA mismatch repair (MMR) results in tolerance to temozolomide regardless of AGT activity. The purpose of this study was to determine the role of MMR deficiency in mediating resistance in samples from patients with both newly diagnosed malignant gliomas and those who have failed temozolomide therapy. EXPERIMENTAL DESIGN: The roles of AGT and MMR deficiency in mediating resistance in glioblastoma multiforme were assessed by immunohistochemistry and microsatellite instability (MSI), respectively. The mutation status of the MSH6 gene, a proposed correlate of temozolomide resistance, was determined by direct sequencing and compared with data from immunofluorescent detection of MSH6 protein and reverse transcription-PCR amplification of MSH6 RNA. RESULTS: Seventy percent of newly diagnosed and 78% of failed-therapy glioblastoma multiforme samples expressed nuclear AGT protein in > or = 20% of cells analyzed, suggesting alternate means of resistance in 20% to 30% of cases. Single loci MSI was observed in 3% of patient samples; no sample showed the presence of high MSI. MSI was not shown to correlate with MSH6 mutation or loss of MSH6 protein expression. CONCLUSIONS: Although high AGT levels may mediate resistance in a portion of these samples, MMR deficiency does not seem to be responsible for mediating temozolomide resistance in adult malignant glioma. Accordingly, the presence of a fraction of samples exhibiting both low AGT expression and MMR proficiency suggests that additional mechanisms of temozolomide resistance are operational in the clinic.

Bevacizumab plus irinotecan in recurrent WHO grade 3 malignant gliomas.

PURPOSE: Although patients with newly diagnosed WHO grade 3 malignant glioma have a more favorable prognosis than those with WHO grade 4 malignant glioma, salvage therapies following recurrence offer essentially palliative benefit. We did a phase II trial of bevacizumab, a monoclonal antibody to vascular endothelial growth factor, in combination with irinotecan for patients with recurrent grade 3 malignant glioma. EXPERIMENTAL DESIGN: Upon documentation of adequate safety among an initial cohort of nine patients treated with bevacizumab (10 mg/kg) and irinotecan every 14 days, a second cohort (n=24) was treated with bevacizumab (15 mg/kg) every 3 weeks with irinotecan on days 1, 8, 22, and 29 of each 42-day cycle. For both cohorts, the dose of irinotecan was 340 mg/m(2) for patients on enzyme-inducing antiepileptic drugs (EIAED) and 125 mg/m(2) for patients not on EIAEDs. After each 6-week cycle, patients were evaluated with a physical examination and magnetic resonance imaging. RESULTS: The 6-month progression-free survival was 55% (95% confidence interval, 36-70%). The 6-month overall survival was 79% (95% confidence interval, 61-89%). Twenty patients (61%) had at least a partial response. Outcome did not differ between the two treatment cohorts. Significant adverse events were infrequent and included a central nervous system hemorrhage in one patient, and one patient who developed thrombotic thrombocytopenic purpura. CONCLUSION: Bevacizumab and irinotecan is an active regimen with acceptable toxicity for patients with recurrent WHO grade 3 malignant glioma.

Efficacy of high-dose chemotherapy or standard salvage therapy in patients with recurrent medulloblastoma.

The efficacy of high-dose chemotherapy (HDC) or standard salvage therapy was evaluated in patients with recurrent medulloblastoma (MBL) using retrospective chart review of all patients with recurrent MBL treated at Duke University Medical Center between 1995 and 2005 and who had undergone HDC with or without radiotherapy (RT) or standard salvage therapy after relapse. A total of 30 patients were diagnosed with recurrent MBL after standard RT alone or chemotherapy with RT. Nineteen patients (7 who received no RT before recurrence [group A] and 12 who received definitive RT before recurrence [group B]) underwent surgery and/or induction chemotherapy followed by HDC plus autologous stem-cell rescue. Eleven patients (group C) underwent standard salvage therapy. Six of seven group A patients also received standard RT just before or after recovery from HDC, and 5 of 12 group B patients received adjuvant palliative focal RT post-HDC. At a median follow-up of 28 months, three of seven patients in group A are alive and disease-free at >or=34, >or=110, and >or=116 months, respectively, post-HDC. All patients in groups B and C have died of tumor, at a median of 35 months and 26 months from HDC and standard salvage therapy, respectively. HDC or standard salvage therapy was ineffective in our patients with recurrent MBL who had received standard RT before recurrence. The favorable impact of HDC on disease control in the two long-term survivors cannot be clearly established due to the cofounding effect of definitive RT postrecurrence.

Safety and pharmacokinetics of dose-intensive imatinib mesylate plus temozolomide: phase 1 trial in adults with malignant glioma.

We determined the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of imatinib mesylate, an inhibitor of the receptor tyrosine kinases platelet-derived growth factor receptor (PDGFR), the proto-oncogene product c-kit, and the fusion protein Bcr-Abl, when administered for 8 days in combination with temozolomide (TMZ) to malignant glioma (MG) patients. MG patients who had not failed prior TMZ were eligible to receive TMZ at a dose of 150-200 mg/m(2) per day on days 4-8 plus imatinib mesylate administered orally on days 1-8 of each 4-week cycle. Patients were stratified based on concurrent administration of CYP3A4-inducing antiepileptic drugs (EIAEDs). The imatinib dose was escalated in successive cohorts of patients independently for each stratum. Imatinib, at doses ranging from 400 mg to 1,200 mg, was administered with TMZ to 65 patients: 52 (80%) with glioblastoma multiforme (GBM) and 13 (20%) with grade III MG. At enrollment, 34 patients (52%) had stable disease, and 33 (48%) had progressive disease; 30 patients (46%) were on EIAEDs. The MTD of imatinib for patients concurrently receiving or not receiving EIAEDs was 1,000 mg. DLTs were hematologic, gastrointestinal, renal, and hepatic. Pharmacokinetic analyses revealed lowered exposures and enhanced clearance among patients on EIAEDs. Among GBM patients with stable disease at enrollment (n=28), the median progression-free and overall survival times were 41.7 and 56.1 weeks, respectively. Imatinib doses up to 1,000 mg/day for 8 consecutive days are well tolerated when combined with standard TMZ dosing for MG patients. A subsequent phase 2 study is required to further evaluate the efficacy of this regimen for this patient population.

A pilot study: 131I-antitenascin monoclonal antibody 81c6 to deliver a 44-Gy resection cavity boost.

The purpose of this study was to determine the feasibility and assess the efficacy and toxicity, among newly diagnosed malignant glioma patients, of administering (131)I-labeled murine antitenascin monoclonal antibody 81C6 ((131)I-81C6) into a surgically created resection cavity (SCRC) to achieve a patient-specific, 44-Gy boost to the 2-cm SCRC margin. A radioactivity dose of (131)I-81C6 calculated to achieve a 44-Gy boost to the SCRC was administered, followed by conventional external beam radiotherapy (XRT) and chemotherapy. Twenty-one patients were enrolled in the study: 16 with glioblastoma multiforme (GBM) and 5 with anaplastic astrocytoma. Twenty patients received the targeted 44-Gy boost (+/-10%) to the SCRC. Attributable toxicity was mild and limited to reversible grade 3 neutropenia or thrombocytopenia (n = 3; 14%), CNS wound infections (n = 3; 14%), and headache (n = 2; 10%). With a median follow-up of 151 weeks, median overall survival times for all patients and those with GBM are 96.6 and 90.6 weeks, respectively; 87% of GBM patients are alive at 1 year. It is feasible to consistently achieve a 44-Gy boost dose to the SCRC margin with patient-specific dosing of (131)I-81C6. Our study regimen ((131)I-81C6 + XRT + temozolomide) was well tolerated and had encouraging survival. To determine if selection of good-prognosis patients affects outcome associated with this approach, the U.S. Food and Drug Administration has approved a trial randomizing newly diagnosed GBM patients to either our study regimen or standard XRT plus temozolomide.

Phase II trial of bevacizumab and irinotecan in recurrent malignant glioma.

PURPOSE: Recurrent grade III-IV gliomas have a dismal prognosis with minimal improvements in survival seen following currently available salvage therapy. This study was conducted to determine if the combination of a novel antiangiogenic therapy, bevacizumab, and a cytotoxic agent, irinotecan, is safe and effective for patients with recurrent grade III-IV glioma. EXPERIMENTAL DESIGN: We conducted a phase II trial of bevacizumab and irinotecan in adults with recurrent grade III-IV glioma. Patients with evidence of intracranial hemorrhage on initial brain magnetic resonance imaging were excluded. Patients were scheduled to receive bevacizumab and irinotecan i.v. every 2 weeks of a 6-week cycle. Bevacizumab was administered at 10 mg/kg. The dose of irinotecan was determined based on antiepileptic use: patients taking enzyme-inducing antiepileptic drugs received 340 mg/m(2), whereas patients not taking enzyme-inducing antiepileptic drugs received 125 mg/m(2). Toxicity and response were assessed. RESULTS: Thirty-two patients were assessed (23 with grade IV glioma and 9 with grade III glioma). Radiographic responses were noted in 63% (20 of 32) of patients (14 of 23 grade IV patients and 6 of 9 grade III patients). The median progression-free survival was 23 weeks for all patients (95% confidence interval, 15-30 weeks; 20 weeks for grade IV patients and 30 weeks for grade III patients). The 6-month progression-free survival probability was 38% and the 6-month overall survival probability was 72%. No central nervous system hemorrhages occurred, but three patients developed deep venous thromboses or pulmonary emboli, and one patient had an arterial ischemic stroke. CONCLUSIONS: The combination of bevacizumab and irinotecan is an active regimen for recurrent grade III-IV glioma with acceptable toxicity.

Temozolomide in children with progressive low-grade glioma.

We conducted a phase II study to assess the efficacy of oral temozolomide (TMZ) in children with progressive low-grade glioma. Thirty eligible patients were enrolled on this study. Median age at enrollment was 10 years (range, 4-18 years). Eligible patients received TMZ (200 mg/m(2) per day) by mouth for five days every four weeks. Patients received a median of nine cycles (range, 2-12 cycles) of treatment. Best responses in the 26 patients (86%) with optic pathway glioma (OPG)/pilocytic astrocytoma (PA) included partial response in 3 patients (11%), minor response in 1 (4%), stable disease in 10 (38%), and progressive disease in 12 (46%). Only one of four patients with fibrillary astrocytoma had stable disease for 29 months after TMZ. The overall disease stabilization rate in patients with OPG/PA was 54%, and disease control was maintained for a median interval of 34 months. Seventeen of 26 patients had progressive disease either on or off therapy, and three have died of disease. The two-year progression-free and overall survivals in patients with OPG/PA were 49% (95% CI, 30%-67%) and 96% (95% CI, 89%-100%), respectively. Worst toxicity related to TMZ in all 30 patients included grade 2-4 thrombocytopenia in seven patients, grade 2-4 neutropenia in seven, grade 2 skin rash in one, and intratumor hemorrhage in one. TMZ given in this schedule was successful in stabilizing disease in a significant proportion of the patients with OPG/PA, with manageable toxicity.

Phase II study of Cloretazine for the treatment of adults with recurrent glioblastoma multiforme.

Cloretazine (VNP40101M) is a newly synthesized alkylating agent belonging to a novel class of alkylating agents called 1,2-bis(sulfonyl)hydrazines. Agents that belong to this class do not produce vinylating and chloroethylating species, and hence this class of alkylating agents is thought to have minimal systemic toxicity. Cloretazine produces two short-lived active species: 1,2-bis(methylsulfonyl)-1-(2-chloroethyl) hydrazine (a chloroethylating species) and a thiophilic carbamoylating methylisocyanate species. The chloroethylating species preferentially produces lesions at the O(6) position of guanine. The methylisocyanate species may inhibit O(6)-alkylguanine-DNA alkyltransferase, an important mechanism of resistance against alkylating agents. The purpose of this study was to determine the efficacy and tolerability of Cloretazine in patients with recurrent glioblastoma multiforme. The basis for the determination of efficacy was the proportion of patients alive without evidence of disease progression six months after initiation of treatment. Patients with recurrent glioblastoma multiforme received Cloretazine (300 mg/m(2)) intravenously every six weeks. Radiographic response, survival data, and toxicity were assessed. Thirty-two patients were enrolled. Median age was 56 years; 24 patients (75%) were men. At six months, two patients were alive and progression free, so the six-month progression-free survival (PFS) was 6%. The median PFS was 6.3 weeks. There were no objective radiographic responses. Twelve patients had stable disease for at least one cycle, but only two patients received more than three cycles. Nine patients experienced grade 4 thrombocytopenia and three patients experienced grade 4 neutropenia. Cloretazine administered every six weeks was relatively well tolerated, although this schedule has insignificant activity for patients with recurrent glioblastoma multiforme.

Phase 1 trial of gefitinib plus sirolimus in adults with recurrent malignant glioma.

PURPOSE: To determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of gefitinib, a receptor tyrosine kinase inhibitor of the epidermal growth factor receptor, plus sirolimus, an inhibitor of the mammalian target of rapamycin, among patients with recurrent malignant glioma. PATIENTS AND METHODS: Gefitinib and sirolimus were administered on a continuous daily dosing schedule at dose levels that were escalated in successive cohorts of malignant glioma patients at any recurrence who were stratified based on concurrent use of CYP3A-inducing anticonvulsants [enzyme-inducing antiepileptic drugs, (EIAED)]. Pharmacokinetic and archival tumor biomarker data were also assessed. RESULTS: Thirty-four patients with progressive disease after prior radiation therapy and chemotherapy were enrolled, including 29 (85%) with glioblastoma multiforme and 5 (15%) with anaplastic glioma. The MTD was 500 mg of gefitinib plus 5 mg of sirolimus for patients not on EIAEDs and 1,000 mg of gefitinib plus 10 mg of sirolimus for patients on EIAEDs. DLTs included mucositis, diarrhea, rash, thrombocytopenia, and hypertriglyceridemia. Gefitinib exposure was not affected by sirolimus administration but was significantly lowered by concurrent EIAED use. Two patients (6%) achieved a partial radiographic response, and 13 patients (38%) achieved stable disease. CONCLUSION: We show that gefitinib plus sirolimus can be safely coadministered on a continuous, daily dosing schedule, and established the recommended dose level of these agents in combination for future phase 2 clinical trials.

Quantitative analysis of O6-alkylguanine-DNA alkyltransferase in malignant glioma.

Promoter hypermethylation of the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT) has been associated with an enhanced response to chloroethylating and methylating agents in patients with malignant glioma. The purpose of this study was to compare three distinct yet related indices for measuring AGT to determine if these assays could be used interchangeably when AGT status is to be used to guide chemotherapeutic decisions. Real-time methylation-specific PCR (MSP), assessed as the ratio of methylated AGT copies to internal beta-actin control, was used to quantitate AGT hypermethylation in 32 glioma samples. Data were compared with AGT enzyme activity as well as immunohistochemical detection of AGT protein from the same samples. Hypermethylation of the AGT promoter was detected in 19 of 31 (61%) samples evaluable by MSP. Low-level AGT, defined as <20% nuclear AGT staining by immunohistochemistry, was found in 10 of 32 samples (31%), whereas 12 of 32 (38%) had low levels of AGT activity. Correlation of immunohistochemistry to AGT activity was statistically significant (P = 0.014) as was the correlation of immunohistochemistry to MSP (P = 0.043), whereas MSP compared with AGT activity (P = 0.246) was not significant. Cross-tabulation of immunohistochemistry and MSP data based on prognostic groups, where good prognosis was represented by an immunohistochemistry of <20% and an MSP ratio >12, showed no significant relationship (P = 0.214), suggesting that one assay cannot be used interchangeably for another. The observed discordance between respective measures of AGT based on prognosis supports further standardization of AGT assays designed to guide therapeutic practice. The data also suggest that consideration be given to the large population of AGT-expressing cells within samples when therapeutic strategies based on tumor methylation are used.

Phase I trial of temozolomide plus O6-benzylguanine for patients with recurrent or progressive malignant glioma.

PURPOSE: We conducted a two-phase clinical trial in patients with progressive malignant glioma (MG). The first phase of this trial was designed to determine the dose of O6-BG effective in producing complete depletion of tumor AGT activity for 48 hours. The second phase of the trial was designed to define the maximum tolerated dose (MTD) of a single dose of temozolomide when combined with O6-BG. In addition, plasma concentrations of O6-BG and O6-benzyl-8-oxoguanine were evaluated after O6-BG. PATIENTS AND METHODS: For our first phase of the clinical trial, patients were scheduled to undergo craniotomy for AGT determination after receiving a 1-hour O6-BG infusion at 120 mg/m2 followed by a continuous infusion at an initial dose of 30 mg/m2/d for 48 hours. The dose of the continuous infusion of O6-BG escalated until tumor AGT was depleted. Once the O6-BG dose was established a separate group of patients was enrolled in the second phase of clinical trial, in which temozolomide, administered as a single dose at the end of the 1-hour O6-BG infusion, was escalated until the MTD was determined. RESULTS: The O6-BG dose found to be effective in depleting tumor AGT activity at 48 hours was an IV bolus of 120 mg/m2 over 1 hour followed by a continuous infusion of 30 mg/m2/d for 48 hours. On enrolling 38 patients in six dose levels of temozolomide, the MTD was established at 472 mg/m2 with dose-limiting toxicities limited to myelosuppression. CONCLUSION: This study provides the foundation for a phase II trial of O6-BG plus temozolomide in temozolomide-resistant MG.

Phase II study of imatinib mesylate plus hydroxyurea in adults with recurrent glioblastoma multiforme.

PURPOSE: We performed a phase II study to evaluate the combination of imatinib mesylate, an adenosine triphosphate mimetic, tyrosine kinase inhibitor, plus hydroxyurea, a ribonucleotide reductase inhibitor, in patients with recurrent glioblastoma multiforme (GBM). PATIENTS AND METHODS: Patients with GBM at any recurrence received imatinib mesylate plus hydroxyurea (500 mg twice a day) orally on a continuous, daily schedule. The imatinib mesylate dose was 500 mg twice a day for patients on enzyme-inducing antiepileptic drugs (EIAEDs) and 400 mg once a day for those not on EIAEDs. Assessments were performed every 28 days. The primary end point was 6-month progression-free survival (PFS). RESULTS: Thirty-three patients enrolled with progressive disease after prior radiotherapy and at least temozolomide-based chemotherapy. With a median follow-up of 58 weeks, 27% of patients were progression-free at 6 months, and the median PFS was 14.4 weeks. Three patients (9%) achieved radiographic response, and 14 (42%) achieved stable disease. Cox regression analysis identified concurrent EIAED use and no more than one prior progression as independent positive prognostic factors of PFS. The most common toxicities included grade 3 neutropenia (16%), thrombocytopenia (6%), and edema (6%). There were no grade 4 or 5 events. Concurrent EIAED use lowered imatinib mesylate exposure. Imatinib mesylate clearance was decreased at day 28 compared with day 1 in all patients, suggesting an effect of hydroxyurea. CONCLUSION: Imatinib mesylate plus hydroxyurea is well tolerated and associated with durable antitumor activity in some patients with recurrent GBM.

Novel human IgG2b/murine chimeric antitenascin monoclonal antibody construct radiolabeled with 131I and administered into the surgically created resection cavity of patients with malignant glioma: phase I trial results.

UNLABELLED: Results from animal experiments have shown that human IgG2/mouse chimeric antitenascin 81C6 (ch81C6) monoclonal antibody exhibited higher tumor accumulation and enhanced stability compared with its murine parent. Our objective was to determine the effect of these differences on the maximum tolerated dose (MTD), pharmacokinetics, dosimetry, and antitumor activity of (131)I-ch81C6 administered into the surgically created resection cavity (SCRC) of malignant glioma patients. METHODS: In this phase I trial, eligible patients received a single injection of (131)I-ch81C6 administered through a Rickham catheter into the SCRC. Patients were stratified as newly diagnosed and untreated (stratum A), newly diagnosed after external beam radiotherapy (XRT) (stratum B), and recurrent (stratum C). (131)I-ch81C6 was administered either before (stratum A) or after (stratum B) conventional XRT for newly diagnosed patients. In addition, chemotherapy was prescribed for all patients after (131)I-ch81C6 administration. Dose escalation was performed independently for each stratum. Patients were observed for toxicity and response until death or progressive disease. RESULTS: We treated 47 patients with (131)I-ch81C6 doses up to 4.44 GBq (120 mCi), including 35 with newly diagnosed tumors (strata A and B) and 12 with recurrent disease (stratum C). Dose-limiting hematologic toxicity defined the MTD to be 2.96 GBq (80 mCi) for all patients, regardless of treatment strata. Neurologic dose-limiting toxicity developed in 3 patients; however, none required further surgery to debulk radiation necrosis. Median survival was 88.6 wk and 65.0 wk for newly diagnosed and recurrent patients, respectively. CONCLUSION: The MTD of (131)I-ch81C6 is 2.96 GBq (80 mCi) because of dose-limiting hematologic toxicity. Although encouraging survival was observed, (131)I-ch81C6 was associated with greater hematologic toxicity, probably due to the enhanced stability of the IgG2 construct, than previously observed with (131)I-murine 81C6.

A practical approach to hyperglycemia management in the intensive care unit: evaluation of an intensive insulin infusion protocol.

STUDY OBJECTIVES: To evaluate the effectiveness and safety of maintaining a target blood glucose concentration of 91-130 mg/dl with a standardized, nurse-managed, intensive insulin infusion protocol outside a study setting, and to determine if a statistically significant favorable effect on morbidity and mortality was achieved. DESIGN: Retrospective, observational, chart review. SETTING: Medical and surgical intensive care units (ICUs) in a community teaching hospital. PATIENTS: One hundred forty-three adult patients who received insulin infusions managed at the discretion of the physician over a 1-year period before initiation of the protocol (control group), and 70 patients who received insulin infusions over a 6-month period with infusion dosages titrated by using the protocol (protocol group). MEASUREMENTS AND MAIN RESULTS: Episodes of hypoglycemia, time within target range, mean blood glucose concentration, frequency of measurement, length of ICU stay, duration of mechanical ventilation, and overall mortality were collected. Hypoglycemic episodes were not significantly different between the groups. Blood glucose concentrations were within target range in 34% of all measurements in the protocol group compared with 23% in the control group (p<0.001, relative risk [RR] 1.48, 95% confidence interval [CI] 1.38-1.58). Once target range was reached on one measurement, 43% of concentrations remained in target range in the protocol group compared with 29% in the control group (p<0.001, RR 1.47, 95% CI 1.38-1.56). Frequency of measurements was higher in the protocol group versus control group (p=0.01); however, clinical difference was minimal. Protocol group had lower overall mortality rate (27% [19/70] vs 32% [46/143], p=0.45), reduced mean ICU length of stay (16.7 +/- 10.6 vs 18.4 +/- 16.0 days, p=0.37), and less mechanical ventilation time (16.5 +/- 9.7 vs 17.0 +/- 15.0 days, p=0.79). CONCLUSION: The nurse-managed insulin infusion protocol improved glycemic control with minimal hypoglycemic episodes compared with baseline practice. A trend toward decreased mortality, ICU length of stay, sand days of mechanical ventilation was observed. When compared with other published protocols, our insulin protocol displays comparable effectiveness with the use of less-frequent blood glucose measurements.

Poly(ADP-ribose) polymerase-1 inhibition reverses temozolomide resistance in a DNA mismatch repair-deficient malignant glioma xenograft.

Temozolomide is a DNA-methylating agent used in the treatment of malignant gliomas. In this study, we have examined if inhibition of poly(ADP-ribose) polymerase (PARP) could increase the cytotoxicity of temozolomide, particularly in cells deficient in DNA mismatch repair. Athymic mice, transplanted with mismatch repair-proficient [D-245 MG] or deficient [D-245 MG (PR)] xenografts, were treated with a combination of temozolomide and the PARP inhibitor, INO-1001. For the tumors deficient in mismatch repair, the most effective dose of INO-1001 was found to be 150 mg/kg, given i.p. thrice at 4-hour intervals with the first injection in combination with 262.5 mg/kg temozolomide (0.75 LD(10)). This dose of temozolomide by itself induced no partial regressions and a 4-day growth delay. In two separate experiments, the combination therapy increased the growth delay by 21.6 and 9.7 days with partial regressions observed in four of eight and three of nine mice, respectively. The addition of INO-1001 had a more modest, yet statistically significant, increase in tumor growth delay in the mismatch repair-proficient xenografts. In these experiments, mice were treated with a lower amount of temozolomide (88 mg/kg), which resulted in growth delays of 43.1 and 39.2 days. When the temozolomide treatment was in combination with 200 mg/kg INO-1001, there was an increase in growth delay to 48.9 and 45.7 days, respectively. These results suggest that inhibition of PARP may increase the efficacy of temozolomide in the treatment of malignant gliomas, particularly in tumors deficient in DNA mismatch repair.

Phase II trial of murine (131)I-labeled antitenascin monoclonal antibody 81C6 administered into surgically created resection cavities of patients with newly diagnosed malignant gliomas.

PURPOSE: To assess the efficacy and toxicity of intraresection cavity (131)I-labeled murine antitenascin monoclonal antibody 81C6 and determine its true response rate among patients with newly diagnosed malignant glioma. PATIENTS AND METHODS: In this phase II trial, 120 mCi of (131)I-labeled murine 81C6 was injected directly into the surgically created resection cavity of 33 patients with previously untreated malignant glioma (glioblastoma multiforme [GBM], n = 27; anaplastic astrocytoma, n = 4; anaplastic oligodendroglioma, n = 2). Patients then received conventional external-beam radiotherapy followed by a year of alkylator-based chemotherapy. RESULTS: Median survival for all patients and those with GBM was 86.7 and 79.4 weeks, respectively. Eleven patients remain alive at a median follow-up of 93 weeks (range, 49 to 220 weeks). Nine patients (27%) developed reversible hematologic toxicity, and histologically confirmed, treatment-related neurologic toxicity occurred in five patients (15%). One patient (3%) required reoperation for radionecrosis. CONCLUSION: Median survival achieved with (131)I-labeled 81C6 exceeds that of historical controls treated with conventional radiotherapy and chemotherapy, even after accounting for established prognostic factors including age and Karnofsky performance status. The median survival achieved with (131)I-labeled 81C6 compares favorably with either (125)I interstitial brachy-therapy or stereotactic radiosurgery and is associated with a significantly lower rate of reoperation for radionecrosis. Our results confirm the efficacy of (131)I-labeled 81C6 for patients with newly diagnosed malignant glioma and suggest that a randomized phase III study is indicated.