Phase I study of vandetanib, imatinib mesylate, and hydroxyurea for recurrent malignant glioma

e13007

Background: Malignant glioma (MG), an incurable primary CNS tumor, is characterized by frequent aberrant activation of EGFR, VEGFR, and PDGFR. This study will determine the MTD and DLT of vandetanib (V), a once-daily, oral selective inhibitor of VEGFR and EGFR when combined with imatinib mesylate (IM), an inhibitor of multiple tyrosine kinases including PDGFR and hydroxyurea (H). Methods: Adult recurrent MG patients with ≤ 3 prior recurrences, KPS ≥ 60% and adequate organ function were stratified based on concurrent enzyme-inducing anticonvulsant use (EIAC). Both strata were independently escalated using a “3+3” design. H is administered at 500 mg BID while IM is administered at 500 mg BID for patients on EIAC and 400 mg QD for those not on EIAC. V is increased by 100 mg in successive cohorts beginning at 100 mg and 200 mg for patients not on and on EIAC, respectively. Evaluations were after every other 28-day cycle. Pharmacokinetics of V and IM were obtained on days 1 and 28 of cycle 1. Results: Twenty-six patients (grade 4 MG, n = 20; grade 3 MG, n = 6) have enrolled. Only 1 DLT (reversible grade 4 transaminase elevation; dose level 1) occurred among 22 non-EIAC patients and enrollment to this stratum is planned to continue at dose level 4. The MTD of V for patients on EIAC is 200 mg/day due to 2 of 3 patients developing grade 3 thrombocytopenia at the 300 mg/day dose level. Evidence of therapeutic benefit to date includes 1 partial response and 15 patients (58%) with stable disease for at least 4 weeks, including 4 patients for ≥4 months. Conclusions: Combination of V, IM, and H is well-tolerated in recurrent MG patients. Further accrual is ongoing and an update of outcome, toxicity, and pharmacokinetic analyses will be presented.

No significant financial relationships to disclose.

Phase II study of bevacizumab plus erlotinib for recurrent malignant gliomas

2045

Background: Bevacizumab (B), a neutralizing VEGF monoclonal antibody, has anti-glioma activity as single agent and in combination with cytotoxic therapy. Erlotinib (E), an EGFR tyrosine kinase inhibitor, may exhibit anti-tumor activity in some malignant glioma (MG) patients. B plus E was associated with clinical benefit in several solid tumors. We performed a single-arm, phase II study to evaluate the efficacy of B and E in patients with recurrent MG. Methods: The primary endpoint was 6-month progression-free survival (PFS-6). Radiographic response, pharmacokinetics and correlative biomarkers were secondary endpoints. E was orally administered daily at 200 mg/day for patients not on enzyme-inducing anticonvulsants (EIAC) and 500 mg/day for patients on EIAC. All patients received 10 mg/kg of B intravenously every two weeks. Key eligibility criteria included: age ≥ 18 years; KPS ≥ 60; > 4 weeks from prior surgery, XRT or chemotherapy. Patients with either > 3 prior progressions, requirement for therapeutic anti-coagulation or acute hemorrhage on pre-treatment imaging were excluded. Results: Fifty-six patients with recurrent MG (n = 24 for glioblastoma multiforme [GBM] and n = 32 for anaplastic gliomas [AGs]) were assessable for outcome. The PFS-6 rates were 25% for GBM and 50% for AGs. There was no survival difference between EIAC and non-EIAC groups. Rash (54% grade 1–2 and 38% grade 3) was the most common side effect. Nausea, diarrhea, and fatigue were common but mostly grade 1–2. Serious side effects were rare and included two patients with pulmonary embolism, single patients with either intestinal perforation, ischemic stroke, gastric bleeding, or nasal septal perforation. Pharmacokinetic and tissue biomarker profiles are in preparation. Conclusions: Among heavily pretreated recurrent MG patients, bevacizumab plus erlotinib is tolerated and associated with encouraging anti-tumor benefit.

No significant financial relationships to disclose.

Bevacizumab plus etoposide among recurrent malignant glioma patients: Phase II study final results

2046

Background: Significant therapeutic benefit has been observed among recurrent malignant glioma (MG) patients treated with bevacizumab (BV), a neutralizing monoclonal antibody to vascular endothelial growth factor (VEGF) with or without chemotherapy. In this study, we evaluate the efficacy of BV plus etoposide (E), a topoisomerase inhibitor, among recurrent MG patients. Methods: Recurrent patients with no more than three prior episodes of recurrence are eligible, while those with prior BV treatment or prior intracranial hemorrhage are excluded. The primary outcome measure is 6 month progression-free survival (6-PFS). BV is dosed at 10 mg/kg intravenously every other week. Etoposide is orally administered daily (50 mg/m2) for days 1–21 of each 28-day cycle. Results: Fifty-nine patients (GBM, n = 27; grade 3 MG, n = 32) with a median of 2 prior progressions have enrolled. With a median follow-up of 45 weeks, median overall survival (OS) for GBM and grade 3 MG patients were 46 and 47 weeks, while the 6-PFS is 44% and 40.6%, respectively. The most common toxicities were neutropenia (41%), fatigue (22%), and infection (20%) and were grade 2 in most cases. One patient developed grade 1 intracranial hemorrhage and 1 patient had a grade 4 GI perforation. Conclusions: Combination of bevacizumab and etoposide is well tolerated in recurrent MG patients and is associated with encouraging anti-tumor benefit. Accrual is complete and an update of further treatment and follow-up will be presented.

No significant financial relationships to disclose.

Phase I trial of vendetanib and oral etoposide for recurrent malignant gliomas

e13016

Background: Recurrent malignant gliomas have a poor prognosis, with a median survival of 6–15 months, with grade 4 glioblastomas more aggressive than grade 3 anaplastic astrocytomas or oligodendrogliomas. Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) are critically important in glioma biology. Vandetanib is a multi-kinase inhibitor, predominantly of VEGF and EGF. We report a phase I trial of vandetanib in combination with oral etoposide for recurrent malignant glioma. Methods: Patients with histologically documented recurrent grade 3 or grade 4 malignant glioma were eligible. Patients were treated with daily oral vandetanib and oral etoposide. The trial design was a modified 3 + 3 Phase I design, with the dose levels outlined below. Results: Eighteen patients have been accrued. There was more hematologic toxicity than expected, with 3/6 of the patients enrolled at dose level 1 developing grade 4 neutropenia. There were no DLT's at the -1 dose level. The protocol was amended to decrease the dose of etoposide to 50 mg daily for 21 days, then 7 days off and dose escalation of vandetanib started again at 100 mg daily. Six patients had no dose limiting toxicity at the new dose level 1 of vandetanib 100 mg daily and etoposide 50 mg daily. Dose escalation continues. There has been clinical activity, with patients remaining stable on study for multiple cycles. Conclusions: Vandetanib and oral etoposide appear to interact to produce more marrow toxicity than expected. A phase II trial is planned when the MTD of vandetanib with reduced dose etoposide is determined.

[Table: see text]

No significant financial relationships to disclose.

A phase I study of sunitinib plus irinotecan in the treatment of patients with recurrent malignant glioma

e13024

Background: Malignant glioma (MG), an incurable primary CNS tumor, are highly angiogenic due to overexpression of VEGF/VEGFR. The current study was designed to determine the MTD and DLT of sunitinib (S), a once-daily, oral selective inhibitor of VEGFR when combined with irinotecan (I), a topoisomerase-1 inhibitor among recurrent MG patients. Methods: We employed a ‘3+3‘ dose escalation design to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of S, administered once daily for the first 28 days of each 42 day cycle, with I, administered every 2 weeks. The initial S and I doses were 25 mg/day and 75 mg/m2. Key eligibility criteria included KPS ≥ 70%, adequate organ function and no concurrent CYP3A-inducing anti-epileptics. Pharmacokinetic studies for S are obtained during cycle 1 among 6 additional patients treated at the MTD. Results: Eleven patients (grade 4 MG, n = 6; grade 3 MG, n = 5) have enrolled. No DLTs were observed in cohort 1, but 2 patients experienced hematologic DLT (grade 3 thrombocytopenia, n = 2; grade 4 neutropenia, n = 1) in cohort 2. Therefore the MTD for this regimen is 25 mg of S plus 75 mg/m2 of I. Evidence of therapeutic benefit to date includes 8 patients (73%) with stable disease including 3 who continue on therapy. Conclusions: Combination of sunitinib plus irinotecan is well tolerated in recurrent MG patients at the defined MTD dose level. Accrual to the PK dose expansion cohort continues.

No significant financial relationships to disclose.

Phase I trial of VNP40101M in children with recurrent brain tumors—A Pediatric Brain Tumor Consortium (PBTC) study

2059

Background: VNP40101M, a novel DNA alkylating agent and a potent inhibitor of alkylguanine alkyl transferase (AGT) in pre- clinical studies, was evaluated in a phase I study in children with recurrent brain tumors. Methods: VNP40101M was given intravenously (i.v) daily for 5 days q 6 weeks up to 8 cycles. Using the continual reassessment method, dose escalation was performed independently in pts stratified based on intensity of prior therapy (stratum I-less-heavily pre-treated; stratum II- heavily pre-treated). Dose limiting toxicities (DLTs) and responses were assessed at the end of the first and 2nd cycles of treatment, respectively. Correlative studies included pharmacokinetics and measurement of AGT activity in peripheral blood mononuclear cells (PBMC) before and after treatment. Results: 41 eligible pts (stratum I- 19, stratum II- 22; median age 9.3 yrs, range 0.9 to 21.5) were enrolled on this study. Dose levels (in mg/m2/day) evaluated in Stratum I were 45, 60, and 78 mg; In Stratum II 20, 30, 45, and 60 mg. DLT in evaluable pts was myelosuppression (grade IV neutropenia for > 7 days or any grade IV thrombocytopenia) and occurred in 4/16 pts in stratum I [45 mg (n=1/12), 60 mg (n=1/2), 78 mg (n= 2/2)] and 3/19 pts in stratum II [45 mg (n= 3/4), 60 mg (n=0/1), 30 mg (n= 0/12), and 20 mg (n= 0/2)] respectively. Other significant toxicities post first course included renal failure (n=2), pulmonary (n=2), and fatal infection (n=1). PK studies showed median (range) terminal half-life of 62 mins (7.3 to 522 min). The MTDs in stratum I and II were 45 mg/m2/day and 30 mg/m2/day daily for 5 days q 6 weeks, respectively. Objective responses were observed in one pt each with brain stem glioma and medulloblastoma respectively. PBMC AGT levels did not decrease following VNP40101M treatment. Conclusions: The recommended pediatric phase II dose of VNP40101M given i.v daily for 5 days q 6 weeks is 45 mg/m2/day in less-heavily treated and 30 mg/m2/day in heavily treated pts.

[Table: see text]

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) evaluation in glioblastoma (GBM) patients treated with bevacizumab (BEV) and irinotecan (CPT-11)

2029

Background: Significant responses seen in GBM patients treated with BEV and CPT-11 generated the need to develop ways to predict clinical benefit. DCE-MRI can be used to evaluate the microvasculature within tumors. DCE-MRI uses Ktrans, a volume transfer constant of contrast agent between blood plasma and the extravascular extracellular space, to determine vascular permeability. A 50% reduction in Ktrans is clinically meaningful. We report a phase II trial to determine the correlation between vascular permeability and radiographic response in GBM patients treated with the combination. Methods: Eligibility included patients with recurrent GBM. Both agents were given every 14 days. All patients received BEV at 10 mg/kg IV. CPT-11 was dosed at 340 mg/m2 for patients on enzyme inducing antiepileptic drugs (EIAED) and 125 mg/m2 for patients not on EIAED. Radiographic responses were assessed every 6 weeks. DCE-MRIs were performed before administration of chemotherapy, one day after treatment and after the first cycle. The primary endpoint was to examine the effect of BEV and CPT-11 treatment on vascular permeability as measured by percent change from baseline in Ktrans. Results: Twenty patients were enrolled, with a median age of 49.5 years. Fifteen patients are assessable for response. Best responses include one patient with complete response, 8 with partial response (response rate=60%), six patients with stable disease, and one with disease progression. Ktrans values are available for 13 patients; data are not available for seven patients (too early: 4, technical difficulty: 3). A reduction in Ktrans by 50% was observed in 6 patients one day after treatment and in 12 patients at the end of cycle 1. Changes in Ktrans value were highly correlated with the percentage decline in tumor volume from baseline to end of cycle one (Pearson correlation = 0.82; p=0.0006). Fifteen patients are still on study. Five patients came off due to disease progression. Conclusions: The utilization of DCE-MRI to determine a reduction in vascular permeability following a combination of BEV and CPT-11 is feasible and correlates significantly with the degree of tumor volume decrease.

No significant financial relationships to disclose.

Phase I trial of imatinib mesylate, hydroxyurea and vatalanib for patients with recurrent glioblastoma multiforme (GBM)

2027

Background: Recent studies have demonstrated promising anti-glioma activity of imatinib mesylate (IM) and hydroxyurea (H). Angiogenesis is one of the hallmarks of GBM with VEGF as a key regulator. This study attempts to extend the efficacy of IM and H by adding a VEGF receptor inhibitor, vatalanib (V; PTK787/ZK22584). Methods: We employ a ‘3+3‘ dose escalation design to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of IM and V when administered with fixed dose of H in adult recurrent GBM patients with < 3 prior recurrences, KPS = 70% and adequate organ function. Patients are stratified based on concurrent enzyme-inducing anticonvulsant (EIAC) administration, and both strata (A- not on EIAC and B- on EIAC) are independently dose-escalated. Initial dose levels for stratum A: IM - 400 mg/day; H - 500 mg bid; V- 250 mg bid and for stratum B: IM- 500 bid; H-500 mg bid; V- 500 mg bid. Patients are given only V on day 1–7 of cycle 1 and then IM+H+V daily thereafter. Only cycle 1 is 35 days with subsequent cycles of 28 days. Response is evaluated every other cycle. Pharmacokinetic (PK) studies are performed on days 7 and 35 of cycle 1. Results: Thirty-five recurrent GBM patients have enrolled. The median age is 51.5 (range 31 to 75), 66% are male, and 51% are on EIAC. One DLT (grade 3 thrombocytopenia) occurred in a stratum A patient on dose level three . For stratum B, two DLTs (grade 3 hypertension and ALT elevation) occurred in a patient on dose level two and one DLT (grade 3 fatigue) occurred in a patient on dose level three. MTDs for each stratum have not been reached and accrual is ongoing. PK results are pending. Ten partial responses (29%) have been observed and nine patients remain on study including three who have received more than 6 cycles of therapy. Conclusions: Combination of imatinib, hydroxyurea and vatalanib is safe and well-tolerated with an encouraging rate of radiographic response. Further accrual is in progress to define the MTD.

No significant financial relationships to disclose.

Phase II trial of Gliadel plus O6-benzylguanic (O6-BG) for patients with recurrent glioblastoma multiforme

2036

Background: The major mechanism of resistance to alkylnitrosourea therapy involves the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT) which removes chloroethylation or methylation damage from the O6- position of guanine. O6-BG is an AGT substrate that inhibits AGT by suicide inactivation. A previous phase III randomized, placebo- controlled trial has shown that Gliadel wafer (G) significantly prolongs 6-month survival (55.5% for G vs. 35.6% for placebo) and median survival (28 weeks for G vs. 20 weeks for placebo) in patients with recurrent glioblastoma multiforme (GBM) (Brem et al 1995). Despite the success of G in prolonging survival we may be able to improve on this success by depleting AGT. Methods: Thus, we have designed a phase 2 trial where we define the activity and the toxicity of G in combination with a 5-day infusion of O6-BG in patients with recurrent GBM. In a prior study 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. In order to guarantee depletion of tumor AGT activity for at least 5 days after G placement, this O6-BG bolus was repeated on days 3 and 5 while continuing the infusion. Results: To date, 47 patients have been enrolled out of a planned accrual of 50 patients. The 6-month survival is 80% and the median survival is 47 weeks. The adverse events include the following: 3 episodes of grade 3 CSF leak (6%), 7 episodes of grade 3 wound infection at craniotomy site (15%), 6 episodes of hyponatremia (13%), 3 episodes of hydrocephalus (6%), 1 episode of hygroma (2%), 1 episode of infectious meningitis (2%), 1 episode of arachnoiditis (2%), 1 episode of grade 3 fever (2%). Conclusions: Thus far, this data demonstrates an increase in the efficacy of G when combined with O6-BG. Three additional patients will be enrolled for a total accrual of 50 patients.

[Table: see text]

Phase II open-label, safety, pharmacokinetic and efficacy study of 2-methoxyestradiol nanocrystal colloidal dispersion administered orally to patients with recurrent glioblastoma multiforme

2065

Background: 2-methoxyestradiol (2ME2) inhibits tumor cell proliferation and induces apoptosis by inhibiting microtubule polymerization and increasing reactive oxygen species-induced cell damage. In addition, 2ME2 downregulates HIF-1a at the posttranscriptional level and inhibits HIF-1a-mediated VEGF expression. Preclinical studies confirm significant in vitro and in vivo anti-glioma activity including tumor regression in combination with temozolomide. We therefore performed a single-center, phase 2 study to evaluate 2ME2 in recurrent glioblastoma multiforme (GBM) patients. Methods: Key eligibility include: adults with GBM at first or second recurrence; measurable disease; Karnofsky performance status = 70% and adequate organ function. 2ME2 was given orally 4 times/day at a dose of 1000mg for the first 11 patients and then escalated to 1500 mg for remaining patients. Patients are evaluated after every 28-day cycle. The primary efficacy endpoint is 6-month progression-free survival. Results: Sixteen patients (14 male) have been enrolled, including 7 at first recurrence and 9 at second recurrence. The median age is 52 years (range, 32–64 years). Thirty-five cycles have been administered to date. Grade II-IV, attributable toxicities include transaminase elevation (grade 3, n=3; grade 2, n=1); hypophosphatemia (grade 3, n=1); anorexia (grade 2, n=1) and rash (grade 2, n=1). Six patients (38%) have achieved stable disease including one minor response. PK studies revealed similar 2ME2 exposures to those achieved among solid tumor patients treated at the same dose level and no differences between GBM patients on or not on CYP3A-inducing anti-epileptic agents. Further accrual and follow-up is ongoing. Conclusions: Continuous daily 2ME2 dosing, administered as a monotherapeutic, is well tolerated and is associated with modest anti-tumor activity among recurrent GBM patients. Combination studies with temozolomide are underway.

No significant financial relationships to disclose.

Bevacizumab, a monoclonal antibody to vascular endothelial growth factor (VEGF), and irinotecan for treatment of malignant gliomas

1506

Background: The prognosis for recurrent malignant gliomas is poor, with a median survival <12 months, median progression-free survival <12 weeks and response rates <20%. Malignant gliomas have high concentrations of VEGF receptors, and the higher the VEGF receptor concentration, the worse the prognosis. Bevacizumab is a humanized IgG1 monoclonal antiblody to VEGF, which is synergistic with chemotherapy for most malignancies. Irinotecan is a topoisomerase 1 inhibitor, and has modest activity against recurrent malignant gliomas. Methods: We report a FDA approved phase II trial of bevacizumab and irinotecan for the treatment of recurrent malignant gliomas. 32 patients were enrolled, 23 with grade IV tumors (glioblastoma multiforme) and 9 with grade III tumors (anaplastic astrocytomas or oligodendrogliomas). All the patients had progressive disease and every patient had received prior radiation therapy and chemotherapy. Patients were treated every other week with bevacizumab 10 mg/kg and irinotecan 125 mg/m2 for patients not taking enzyme inducing anti-epileptic drugs or 340 mg/m2 for patients taking enzyme inducing anti-epileptic drugs. Results: The regimen was well tolerated with no CNS hemorrhages or >grade 1 systemic hemorrhages. Four patients were taken off study for thrombotic complications, 2 pulmonary emboli, 1 deep venous thrombus, and one thrombotic stroke. Two patients were discontinued secondary to grade 2 proteinuria and three were discontinued because they required non-neurosurgical surgery, appendectomy, repair of anal fissures and hip stabilization. The response rate was 63% (19 PRs and 1 CR). The median progression-free survival is 24 weeks. The median overall survival has not been reached, and exceeds 6 months. There have been ten deaths due to disease progression. Conclusions: The combination of bevacizumab and irinotecan is safe and one of the most active regimens against malignant gliomas.

[Table: see text]

Combination of bevacizumab, a monoclonal antibody to vascular endothelial growth factor (VEGF), and temozolomide: Study of cases

11522

Background: The prognosis for glioblastoma multiforme remains poor. Survival is generally limited to less than 1 year. Currently available standard treatments have not allowed, thus far, to prolong survival significantly. Response rates observed in clinical trials evaluating glioblastoma multiforme are usually less than 20%. Knowing that malignant gliomas have high concentrations of VEGF receptors, and the higher the VEGF receptor concentration, the worse the prognosis, we decided to evaluate the efficacy of bevacizumab in malignant brain tumor patients. Bevacizumab is a humanized IgG1 monoclonal antibody to VEGF, which is synergistic with chemotherapy for most malignancies. We performed a phase II study combining bevacizumab with irinotecan for patient with malignant gliomas and observed an unprecedented response rate of 63%. Methods: Building of those results, we decided to treat a number of our patients with voluminous unresectable disease with bevacizumab and temozolomide as an upfront regimen. Temozolomide is an oral methylating agent known effective for primary malignant brain tumor patients. A phase III trial, first presented at the ASCO meeting of 2003, demonstrated the efficacy of temozolomide for newly diagnosed glioblastoma multiforme patients, establishing temozolomide as the new standard of care. Given the known results with temozolomide as monotherapy and the combination of bevacizumab with irinotecan, we treated patients with temozolomide and bevacizumab upfront. Results: With this new combination, some patients demonstrated dramatic improvement clinically and radiographically. The combination has been well tolerated thus far, with no incidence of hemorrhage or arterial thrombosis observed. Conclusions: Results will be updated at the time of presentation.

[Table: see text]

Phase II trial of Gliadel plus O6-benzylguanine (O6-BG) for patients with recurrent glioblastoma multiforme

1568

Background. The major mechanism of resistance to alkylnitrosourea therapy involves the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT) which removes chloroethylation or methylation damage from the O6-position of guanine. O6-BG is an AGT substrate that inhibits AGT by suicide inactivation. A previous phase III randomized, placebo-controlled trial has shown that Gliadel wafer significantly prolongs 6-month survival (55.5% for Gliadel vs. 35.6% for placebo) and median survival (28 weeks for Gliadel vs. 20 weeks for placebo) in patients with recurrent glioblastoma multiforme (GBM) (Brem et al 1995). Despite the success of Gliadel in prolonging survival we may be able to improve on this success by depleting AGT. Methods. Thus, we have designed a phase 2 trial where we define the activity and the toxicity of Gliadel in combination with a 5-day infusion of O6-BG in patients with recurrent GBM. In a prior study 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. In order to guarantee depletion of tumor AGT activity for at least 5 days after Gliadel placement, this O6-BG bolus was repeated on days 3 and 5 while continuing the infusion. Results. To date, 24 patients have been enrolled out of a planned accrual of 50 patients. Seventeen of these patients received prior nitrosourea therapy. The 6-month survival is 68% and the median survival is 36 weeks. The adverse events include the following: 2 episodes of CSF leak (8%), 4 episodes of wound infection at craniotomy site (16%), 5 episodes of grade ≥ 3 seizures (21%) and 3 episodes of hyponatremia (12%). These adverse events were similar in frequency to those seen in patients receiving Gliadel in prior placebo-controlled Gliadel trials. Conclusions. Thus far, this data demonstrates an increase in the efficacy of Gliadel when combined with O6-BG. Twenty-six additional patients will be enrolled for a total accrual of 50 patients.

[Table: see text]

An update on phase I study of dose-escalating imatinib mesylate plus standard-dosed temozolomide for the treatment of patients with malignant glioma

1560

Background: Imatinib mesylate, a kinase inhibitor of the PDGF receptor has been shown to decrease tumor interstitial pressure resulting in enhanced delivery of cytotoxic therapy. Recent phase II trial demonstrated promising anti-glioma activity of imatinib mesylate in combination with chemotherapy, hydroxyurea. Methods: The current phase I study is designed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of imatinib mesylate when combined with temozolomide, a DNA methylator with established efficacy against gliomas. Eligibility criteria include: histologically confirmed malignant glioma; age of at least 18 years; KPS of at least 60%; less than grade 2 intratumoral hemorrhage; adequate hepatic, renal, and bone marrow function and lack of prior failure or significant toxicity following treatment with either imatinib mesylate or temozolomide. Temozolomide is dosed at 200 mg/m2 on days 4–8 of each 28-day cycle. Imatinib mesylate is administered on days 1–8 of each cycle and the dose is escalated in successive cohorts of 3–6 patients via a standard “3+3” dose escalation design. Patients are stratified based on concurrent use of enzyme-inducing anticonvulsants (EIAC) and both strata are independently escalated. Results: To date 47 patients have been enrolled including 40 with GBM and 7 with anaplastic gliomas. Median age is 53.9 years (range 28 to 72); 66% are male and 51% are on EIAC. The MTD has yet to be defined for either stratum. To date DLT of ALT elevation has been observed in one patient from non-EIAC stratum. Two patients discontinued therapy due to toxicities with one asymptomatic intracerebral hemorrhage and one severe hematologic toxicity. Pharmacokinetic sampling has been performed in approximately half of the patients. One patient completed the study (12 cycles) with stable disease. Eleven patients remain on study with one partial response and three patients have undergone more than 10 cycles of therapy with stable disease. Twenty-eight patients (59%) have developed progressive disease and discontinued therapy. Conclusions: Combination of imatinib mesylate and temozolomide is safe and well tolerated. Further accrual and dose escalation are ongoing.

[Table: see text]

A phase I trial of imatinib, hydroxyurea and RAD001 for patients with recurrent malignant glioma

1580

Background: This study attempts to extend the anti-glioma activity of imatinib mesylate (Gleevec, IM) plus hydroxyurea (H), by adding RAD001 (R), an orally bioavailable inhibitor of mTOR, a critical intracellular mediator of signal transduction and metabolism. Methods: We employ a “3+3” dose escalation design to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of IM + H + R administered daily among adult recurrent malignant glioma patients s with ≤ 3 prior recurrences, KPS > 60% and adequate organ function. Patients are stratified based on concurrent enzyme-inducing anticonvulsant use (EIAC), and both strata are independently escalated. Initial dose level for each stratum: IM - 400 mg/day; H - 500 mg bid; R - 2.5 mg/day. Each treatment cycle is 28 days. Response is evaluated every other cycle. Pharmacokinetic (PK) studies are performed on days 1 and 28 of cycle 1. Results: Twenty-two recurrent GBM patients have enrolled. The median age is 53 (range 37 to 75), 41% are male, and 45% are on EIAC. Two DLTs (grade 4 hypercholesterolemia and thrombocytopenia) occurred among 5 patients on dose level one (non-EIAC stratum). No other DLTs have occurred. The dose escalation schema has been amended to include alternate day R dosing. IM PK were consistent with those previously reported for patients on IM and HU. IM clearance on day 1 was 492 ± 247 ml/min in the EIAC stratum and 231 ± 100 ml/min in the non-EIAC stratum. On day 28, IM clearance was decreased in both strata (243 ± 93 ml/min in the EIAC stratum and 116 ± 47 ml/min in the non-EIAC stratum) PK results for HU and R are pending. Nine patients continue on study having received 2–8 cycles of therapy. Four partial responses have been observed and accrual is ongoing. Conclusions: Further accrual is warranted. An update of outcome, toxicity and pharmacokinetic analyses will be presented.

[Table: see text]

Acute toxicity analysis of patients receiving surgery, Gliadel wafer implantation, and postoperative daily temozolomide with radiation therapy for primary high-grade glioma

11504

Background: Treatment of patients with newly diagnosed malignant glioma using Gliadel wafer implantation at initial surgery has been shown to increase survival (Westphal et al 2003). Similarly, administration of temozolomide during and after radiotherapy has also been shown to increase survival in this patient population (Stupp et al 2005). Accordingly use of both Gliadel and temozolomide may be advantageous for these patients although it is possible that the toxicity of these two approaches used together might be prohibitive. Methods: The Preston Robert Tisch Brain Tumor Center at Duke has occasionally treated with this approach over the last several years, and we now present an analysis of the observed acute toxicity. We retrospectively reviewed the Duke patients treated with surgery plus Gliadel wafer placement followed by daily temozolomide (75 mg/m2-150 mg/m2) and radiation therapy. Results: Of 28 patients reviewed, four patients were diagnosed with AA (WHO grade III), two patients were diagnosed with AO (WHO grade III) and the remaining 22 patients were diagnosed with glioblastoma multiforme (WHO grade IV). Two of the 28 7.1%) patients experienced grade 3 or 4 hematologic toxicity during radiation and daily temozolomide therapy. This is similar to the 7% of patients found to have hematologic toxicity reported by Stupp et al (2005). Three patients (10.7%) had grade 3 or 4 seizure activity. Two patients (7.1%) had grade 4 pulmonary emboli. No events of cerebral edema or wound complications were noted in this review of patient events following Gliadel wafer placement. Conclusions: In summary, the addition of Gliadel wafer placement at the time of surgery followed by radiation therapy with concurrent daily low dose temozolomide does not appear to have significant acute toxicity over that observed with radiation therapy and daily temozolomide. Future formal trials combining these therapeutic strategies may allow evaluation of the possible survival advantage associated with this approach.

[Table: see text]

Central nervous system extraosseous Ewing sarcoma: radiologic manifestations of this newly defined pathologic entity

Although these entities are histologically similar, recent advances in molecular genetics have allowed the distinction of central nervous system extraosseous Ewing sarcoma (CNS-EES) from central primitive neuroectodermal tumors (c-PNET) including medulloblastoma and supratentorial PNET. We present 2 cases of pathologically confirmed CNS-EES. Knowledge of CNS-EES as a distinct entity enables the neuroradiologist to suggest the proper diagnosis and the need for special immuno-histochemical and molecular studies to confirm the diagnosis. Because treatment and prognosis are vastly different, the proper diagnosis of CNS-EES versus c-PNET is critical.