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.     

Phase I trial of irinotecan plus temozolomide in adults with recurrent malignant glioma

BACKGROUND: The authors determined the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of irinotecan (CPT-11), a topoisomerase I inhibitor, when administered with temozolomide among patients with recurrent malignant glioma (MG). METHODS: Patients with MG at any recurrence received temozolomide (TMZ) at a dose of 200 mg/m(2)/day on Days 1-5 plus CPT-11 administered as a 90-minute intravenous infusion during Weeks 1, 2, 4, and 5 of each 6-week cycle. Patients were stratified based on concurrent administration of CYP3A4-inducing anticonvulsants (enzyme-inducing antiepileptic drugs [EIAEDs]). The CPT-11 dose was escalated in successive cohorts of patients independently for each stratum. RESULTS: CPT-11, at doses ranging from 40 mg/m(2) to 375 mg/m(2), was administered with TMZ to 107 patients. Ninety-one patients (85%) had recurrent glioblastoma multiforme (GBM) and 16 (15%) had recurrent anaplastic glioma. Sixty-eight patients (64%) were given EIAEDs. The MTD of CPT-11 for patients concurrently receiving and not receiving EIAEDs was 325 mg/m(2) and 125 mg/m(2), respectively. The DLTs were hematologic, gastrointestinal, and hepatic. Fifteen patients (14%) achieved either a radiographic complete (n = 5) or partial (n = 10) response across a wide range of CPT-11 dose levels. Patients with recurrent GBM who achieved radiographic response had a median time to disease progression of 54.9 weeks. CONCLUSIONS: The current study built on preclinical observations designed to increase the clinical activity of topoisomerase I inhibitors. CPT-11, administered at full dose levels, was well tolerated in combination with TMZ. Furthermore, durable responses were observed in this recurrent population. Ongoing Phase II studies will evaluate the efficacy of this regimen and its application to other malignancies.     

Phase I pharmacokinetic study of the vascular endothelial growth factor receptor tyrosine kinase inhibitor vatalanib (PTK787) plus imatinib and hydroxyurea for malignant glioma

BACKGROUND:

This study determined the maximum tolerated dose (MTD) and dose‐limiting toxicities (DLT) of the oral vascular endothelial growth factor receptor (VEGFR) inhibitor, vatalanib, when administered with imatinib and hydroxyurea on a continuous daily schedule among recurrent malignant glioma patients.

METHODS:

All patients received 500 mg of hydroxyurea twice daily. Imatinib was dosed at 400 mg per day for patients not taking enzyme‐inducing antiepileptic drugs (EIAEDs; stratum A) and at 500 mg twice‐a‐day for patients taking EIAEDs (stratum B). Vatalanib was escalated from 500 mg to 1250 mg twice daily in successive cohorts, independently for each stratum. Pharmacokinetics of each drug were assessed.

RESULTS:

A total of 37 recurrent patients, 34 (92%) with glioblastoma and 3 (8%) with grade 3 malignant glioma, were enrolled. Nineteen patients (51%) were taking EIAEDs. The MTD of vatalanib for all patients was 1000 mg twice‐a‐day. DLTs were hematologic, gastrointestinal, renal, and hepatic. No patients developed intracranial hemorrhage. Concurrent administration of imatinib and hydroxyurea did not affect vatalanib exposure, but EIAEDs decreased vatalanib and imatinib plasma exposures.

CONCLUSIONS:

Vatalanib doses up to 1000 mg twice‐a‐day combined with imatinib and hydroxyurea were well tolerated. Strategies to target tumor blood vessel endothelial cells and pericytes by inhibiting VEGFR and platelet‐derived growth factor, respectively, were safe among recurrent malignant glioma patients and may enhance antiangiogenesis activity. Cancer 2009. © 2009 American Cancer Society.     

Phase II study of imatinib mesylate and hydroxyurea for recurrent grade III malignant gliomas

Purpose Recent reports demonstrate the activity of imatinib mesylate, an ATP-mimetic, tyrosine kinase inhibitor, plus hydroxyurea, a ribonucleotide reductase inhibitor, in patients with recurrent glioblastoma multiforme. We performed the current phase 2 study to evaluate this regimen among patients with recurrent WHO grade III malignant glioma (MG). Patients and method Patients with grade III MG 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 anti-epileptic drugs (EIAEDs) and 400 mg once a day for those not on EIAEDs. Clinical assessments were performed monthly and radiographic assessments were obtained at least every 2 months. The primary endpoint was 6-month progression-free survival (PFS) rate. Results Thirty-nine patients were enrolled. All patients had progressive disease after prior radiotherapy and at least temozolomide-based chemotherapy. The median number of episodes of prior progression was 2 (range, 1–7) and the median number of prior treatment regimens was 3 (range, 1–8). With a median follow-up of 82.9 weeks, 24% of patients were progression-free at 6 months. The radiographic response rate was 10%, while 33% achieved stable disease. Among patients who achieved at least stable disease at first evaluation, the 6-month and 12-month PFS rates were 53% and 29%, respectively. The most common grade 3 or greater toxicities were hematologic and complicated less than 4% of administered courses. Conclusion Imatinib mesylate plus hydroxyurea, is well tolerated and associated with anti-tumor activity in some patients with recurrent grade 3 MG. Supported by National Institutes of Health grant nos. 1-P50-CA108786-01, NS20023 and CA11898 and by grant no. MO1 RR 30 through the General Clinical Research Centers Program, National Center for Research Resources, National Institutes of Health.     

Phase-1 trial of gefitinib and temozolomide in patients with malignant glioma: a North American brain tumor consortium study

Purpose This is a phase-I study of gefitinib in combination with temozolomide in patients with gliomas. The goal of the study was to define the maximum tolerated dose (MTD) and to characterize the pharmacokinetics of gefitinib when combined with temozolomide. Patients and methods Patients were stratified according to co-administration of enzyme-inducing anti-epileptic drugs (EIAEDs). There were 26 evaluable patients enrolled (16 on EIAEDs, 10 not on EIAEDs). All but seven patients had Glioblastoma Multiforme (GBM), and only six cases had a Karnosfsky Performance Status (KPS) of less than 80; median age was 51 years. All had received prior radiotherapy and 14 patients had no prior chemotherapy. The starting dose of temozolomide was 150 mg/m²/day for 5 days every 28 days and could be escalated to a maximum dose of 200 mg/m²/day in subsequent cycles. The starting dose of gefitinib was 500 mg/day given by mouth on a continuous basis. Dose-limiting toxicity was assessed in cycle one only. Results For patients on EIAEDs, the MTD of gefitinib was 1,000 mg/day in combination with temozolomide. Dose-limiting toxicity (DLT) was due to diarrhea, nausea and vomiting. For patients not on EIAEDs, the MTD was 250 mg/day in combination with temozolomide. The DLT was due to increases in liver transaminases. Rash was not a significant toxicity at these dose levels. The peak concentration and AUC_0-24hr at the 500 mg dose level was 1.8 and 2.5-fold lower, respectively, in the EIAED group compared to the non-EIAED group; trough levels of gefitinib increased in both groups consistent with the reported terminal half-life ranging from 27 to 51 h. Conclusion The recommended phase-2 dose of gefitinib when used in combination with temozolomide is 1,000 and 250 mg/day, respectively, for patients on or not on EIAEDs.     

Multicentre phase II studies evaluating imatinib plus hydroxyurea in patients with progressive glioblastoma

Background:

We evaluated the efficacy of imatinib mesylate in addition to hydroxyurea in patients with recurrent glioblastoma (GBM) who were either on or not on enzyme-inducing anti-epileptic drugs (EIAEDs).

Methods:

A total of 231 patients with GBM at first recurrence from 21 institutions in 10 countries were enrolled. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 600 mg per day for patients not on EIAEDs and at 500 mg twice a day if on EIAEDs. The primary end point was radiographic response rate and secondary end points were safety, progression-free survival at 6 months (PFS-6), and overall survival (OS).

Results:

The radiographic response rate after centralised review was 3.4%. Progression-free survival at 6 months and median OS were 10.6% and 26.0 weeks, respectively. Outcome did not appear to differ based on EIAED status. The most common grade 3 or greater adverse events were fatigue (7%), neutropaenia (7%), and thrombocytopaenia (7%).

Conclusions:

Imatinib in addition to hydroxyurea was well tolerated among patients with recurrent GBM but did not show clinically meaningful anti-tumour activity.     

A phase I/II trial of vandetanib for patients with recurrent malignant glioma

Vandetanib is a once-daily multitargeted tyrosine kinase inhibitor of vascular endothelial growth factor receptor–2, epidermal growth factor receptor, and the rearranged-during-transfection oncogene. A phase I trial was conducted to describe the pharmacokinetics of vandetanib in patients with recurrent glioma on enzyme-inducing anti-epileptic drugs (EIAEDs) and to identify the maximum tolerated dose (MTD) in this population. A phase II trial evaluated the efficacy of vandetanib in patients with recurrent malignant glioma not on EIAEDs as measured by 6-month progression-free survival (PFS6). In the phase I trial, 15 patients were treated with vandetanib at doses of 300, 400, and 500 mg/day, in a standard dose-escalation design. The MTD in patients on EIAEDs was 400 mg/day, and steady-state levels were similar to those measured in patients not on EIAEDs. Dose-limiting toxicities were prolonged QTc and thromboembolism. Thirty-two patients with recurrent glioblastoma multiforme (GBM) and 32 patients with recurrent anaplastic gliomas (AGs) were treated in the phase II trial, at a dosage of 300 mg/day on 28-day cycles. Six patients (4 GBM, 2 AG) had radiographic response. PFS6 was 6.5% in the GBM arm and 7.0% in the AG arm. Median overall survival was 6.3 months in the GBM arm and 7.6 months in the AG arm. Seizures were an unexpected toxicity of therapy. Vandetanib did not have significant activity in unselected patients with recurrent malignant glioma.     

A phase I trial of erlotinib in patients with nonprogressive glioblastoma multiforme postradiation therapy,and recurrent malignant gliomas and meningiomas

The objective of this phase I study was to determine the maximal tolerated dose (MTD) of erlotinib in patients with recurrent malignant gliomas (MGs) or recurrent meningiomas on enzyme-inducing antiepileptic drugs (EIAEDs). Dose escalation was by a standard 3 × 3 design. The initial starting dose of erlotinib was 150 mg daily. If no dose-limiting toxicity (DLT) was observed, then dose escalation occurs as follows: 200 mg/day, 275 mg/day, and then increased in 125 mg increments until the MTD was reached. The MTD was defined as the dose where ≤1 of 6 patients experienced a DLT and the dose above had 2 or more DLTs. The MTD was 650 mg/day; the observed DLTs were grade 3 rash in 2 patients at 775 mg/day. Pharmacokinetic analysis showed a significant influence of EIAEDs on the metabolism of erlotinib when compared with our phase II data published separately. Primary toxicities were rash and diarrhea. The MTD of erlotinib in patients receiving EIAEDs is substantially higher than the standard dose of 150 mg. This has important implications for further development of this drug in the treatment of MG as well as the optimal management of patients with other malignancies such as NSCLC who are on enzyme-inducing drugs.     

Phase 1 trial of temozolomide plus irinotecan plus O6‐benzylguanine in adults with recurrent malignant glioma

BACKGROUND:

The current study was a phase 1 clinical trial conducted with patients who had recurrent or progressive malignant glioma (MG). The trial was designed to determine the maximum tolerated dose (MTD) and toxicity of irinotecan (CPT‐11) when administered with temozolomide (TMZ) and O⁶‐benzylguanine (O⁶‐BG).

METHODS:

All 3 drugs, CPT‐11, TMZ, and O⁶‐BG, were administered on Day 1 of a 21‐day treatment. First, patients were treated with a 1‐hour bolus infusion of O⁶‐BG at a dose of 120 mg/m² followed immediately by a 48‐hour continuous infusion of O⁶‐BG at a dose of 30 mg/m²/d. Second, within 60 minutes of the end of the 1‐hour bolus infusion of O⁶‐BG, TMZ was administered orally at a dose of 355 mg/m². Third, 1 hour after administration of TMZ, CPT‐11 was infused over 90 minutes. Patients were accrued to 1 of 2 strata based on CYP3A1‐ and CYP3A4‐inducing antiepileptic drug (EIAED) use; dose escalation was conducted independently within these strata.

RESULTS:

Fifty‐five patients were enrolled. In both strata, the dose‐limiting toxicities were hematologic and included grade 4 neutropenia, febrile neutropenia, leukopenia, and/or thrombocytopenia. For Stratum 1 (EIAEDs), when TMZ was administered at a dose of 355 mg/m², the MTD of CPT‐11 was determined to be 120 mg/m². In contrast, for Stratum 2 (no EIAEDs), when TMZ was administered at a dose of 200 mg/m², the MTD of CPT‐11 was determined to be 80 mg/m².

CONCLUSIONS:

The authors believe that the results of the current study provide the foundation for a phase 2 trial of O⁶‐BG in combination with CPT‐11 and TMZ in patients with MG. Cancer 2009. © 2009 American Cancer Society.     

Phase II trial of irinotecan plus celecoxib in adults with recurrent malignant glioma

BACKGROUND: In the current study, the authors report a Phase II trial of irinotecan (CPT-11), a topoisomerase I inhibitor active against malignant glioma (MG), with celecoxib, a selective COX-2 inhibitor, among MG patients with recurrent disease. METHODS: Patients with MG at any type of recurrence received CPT-11, administered as a 90-minute intravenous infusion on Weeks 1, 2, 4, and 5 of each 6-week cycle plus celecoxib, which was administered continuously at a dose of 400 mg twice a day. CPT-11 was given at a dose of 350 mg/m(2) for patients receiving enzyme-inducing antiepileptic drugs (EIAEDs) and at a dose of 125 mg/m(2) for those patients not receiving EIAEDs. Assessments were performed after every cycle. The primary endpoint was radiographic response and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and therapeutic safety. RESULTS: Thirty-four of the 37 patients enrolled in the current study (92%) were diagnosed with recurrent GBM and 3 patients (8%) were diagnosed with recurrent anaplastic astrocytoma (AA). Twenty-one patients were receiving EIAEDs and 16 patients were not. The median follow-up time was 76.9 weeks. Concomitant CPT-11 plus celecoxib was found to be well tolerated and safe. Hematologic toxicities of >/= Grade 3 (according the second version of the Common Toxicity Criteria of the National Cancer Institute) reportedly complicated 8.6% of treatment courses. Grade 3 diarrhea, the most commonly reported nonhematologic toxicity, occurred with equal frequency (8%), regardless of whether the patient was receiving EIAED. Six patients (16%), all whom were diagnosed with recurrent GBM, achieved an objective radiographic response whereas an additional 13 patients (35%) achieved stable disease. The median PFS was 11.0 weeks and the 6-month PFS was reported to be 25.1%. The median OS was 31.5 weeks. CONCLUSIONS: The results of the current study confirm that CPT-11 plus celecoxib can be safely administered concurrently at full dose levels, and that this regimen has encouraging activity among heavily pretreated patients with recurrent MG.     

Prognostic relevance of mutations and copy number alterations assessed with targeted next generation sequencing in IDH mutant grade II glioma

Prognosis of recurrent glioblastoma (GBM) is poor with 6-month progression-free survival (PFS6) ranging from 9 to 48% depending on the treatment regimen and use of anti-angiogenic therapies. We sought to study vorinostat (VOR), a histone deacetylase inhibitor, in combination with bevacizumab (BEV) and daily metronomic temozolomide (TMZ) in a Phase I/II trial in recurrent high-grade gliomas (HGGs). This was a Phase I/II open-label, single-arm study in recurrent HGG patients. Phase I primary endpoint was to determine the maximum tolerated dose (MTD) of VOR with BEV and daily TMZ. Phase II primary endpoint was PFS6. Regimen was BEV 10 mg/kg iv every 2 weeks, TMZ 50 mg/m² po daily, and VOR 200 or 400 mg po alternating 7 days on then 7 days off throughout a 28-day cycle. Phase I portion enrolled nine subjects with three receiving VOR 200 mg and 6 receiving VOR 400 mg. With no dose-limiting toxicities (DLTs) at 200 mg and one DLT (thrombocytopenia, Grade 3) at 400 mg, the MTD was 400 mg. Phase II portion enrolled 39 GBM subjects, and PFS6 was 53.8% (95% CI 37.2–67.9%). Of note, 14 subjects had received prior BEV and all had received prior 5-day TMZ. Combination therapy with VOR, BEV, and daily TMZ was well tolerated and safe. While PFS6 was not statistically improved beyond historical controls, it is important to note that this was a heavily pretreated GBM population and further consideration is warranted in a less pretreated group.     

Phase I study of arsenic trioxide and temozolomide in combination with radiation therapy in patients with malignant gliomas

To evaluate the toxicity and maximum tolerated dose (MTD) of arsenic trioxide (ATO) in combination with temozolomide (TMZ) and radiation therapy (RT) in malignant gliomas. A 3?+?3 dose escalation study was performed in patients with newly diagnosed glioblastoma, anaplastic astrocytoma (AA), and anaplastic oligoastrocytoma (AOA). All patients received RT 59?C61?Gy in 28?C33 fractions, TMZ for 42?days, and ATO 1?C2?h prior to RT for 5?days during the first week, then twice weekly until completing RT. Dose levels (DL) were: (1) TMZ 60?mg/m²/ATO 0.2?mg/kg; (2) TMZ 75?mg/m²/ATO 0.2?mg/kg; (3) TMZ 75?mg/m²/ATO 0.25?mg/kg. Dose-limiting toxicity (DLT) was defined as grade 3 non-hematologic toxicity or grade 4 toxicity of any type from enrollment until 3?weeks after finishing RT. 17 patients (13 glioblastoma, 4 AA/AOA) were accrued. Median age was 52 (range 25?C80). Median KPS was 90?%. DLT??s occurred at DL 2 (grade 4 transaminase elevation) and DL 3 (grade 4 neutropenia and grade 3 QTc prolongation). The MTD of TMZ 75?mg/m²/ATO 0.2?mg/kg was safe and well tolerated. A phase II study evaluating the efficacy of this combination is underway.     

Phase I/II study of imatinib mesylate for recurrent malignant gliomas: North American Brain Tumor Consortium Study 99-08.

PURPOSE: Phase I: To determine the maximum tolerated doses, toxicities, and pharmacokinetics of imatinib mesylate (Gleevec) in patients with malignant gliomas taking enzyme-inducing antiepileptic drugs (EIAED) or not taking EIAED. Phase II: To determine the therapeutic efficacy of imatinib. EXPERIMENTAL DESIGN: Phase I component used an interpatient dose escalation scheme. End points of the phase II component were 6-month progression-free survival and response. RESULTS: Fifty patients enrolled in the phase I component (27 EIAED and 23 non-EIAED). The maximum tolerated dose for non-EIAED patients was 800 mg/d. Dose-limiting toxicities were neutropenia, rash, and elevated alanine aminotransferase. EIAED patients received up to 1,200 mg/d imatinib without developing dose-limiting toxicity. Plasma exposure of imatinib was reduced by approximately 68% in EIAED patients compared with non-EIAED patients. Fifty-five non-EIAED patients (34 glioblastoma multiforme and 21 anaplastic glioma) enrolled in the phase II component. Patients initially received 800 mg/d imatinib; 15 anaplastic glioma patients received 600 mg/d after hemorrhages were observed. There were 2 partial response and 6 stable disease among glioblastoma multiforme patients and 0 partial response and 5 stable disease among anaplastic glioma patients. Six-month progression-free survival was 3% for glioblastoma multiforme and 10% for anaplastic glioma patients. Five phase II patients developed intratumoral hemorrhages. CONCLUSIONS: Single-agent imatinib has minimal activity in malignant gliomas. CYP3A4 inducers, such as EIAEDs, substantially decreased plasma exposure of imatinib and should be avoided in patients receiving imatinib for chronic myelogenous leukemia and gastrointestinal stromal tumors. The evaluation of the activity of combination regimens incorporating imatinib is under way in phase II trials.     

Phase II study of Gleevec® plus hydroxyurea (HU) in adults with progressive or recurrent meningioma

We prospectively evaluated the efficacy and safety of imatinib plus hydroxyurea in patients with progressive/recurrent meningioma. A total of 21 patients with progressive/recurrent meningioma were enrolled in this dual center, single-arm, phase II trial. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 400 mg/day for patients not on CYP3A enzyme inducing anti-epileptic drugs (EIAEDs) and at 500 mg twice a day for patients on EIAEDs. The primary endpoint was progression-free survival at 6 months (PFS-6) and secondary endpoints were safety, radiographic response rate, and overall survival (OS). Best radiographic response was stable disease and was observed in 14 patients (67%). PFS-6 for all patients, those with grade I tumors (n = 8) and those with grade II or III tumors (n = 13) was 61.9, 87.5 and 46.2%, respectively. Patients with grade II or III tumors had poorer PFS and OS than those with grade I tumors, (P = 0.025 and P = 0.018) respectively. The only grade 3 or greater adverse event occurring in ≥ 10% of patients was anemia (10%). Imatinib plus hydroxyurea is well tolerated among patients with meningioma but has modest anti-tumor activity for this indication.     

U.S. Food and Drug Administration Drug Approval Summary: conversion of imatinib mesylate (STI571; Gleevec) tablets from accelerated approval to full approval.

Imatinib mesylate (Gleevec, Novartis Pharmaceuticals East Manruer, NJ) received accelerated approval on May 10, 2001 for the treatment of patients with chronic myeloid leukemia (CML) in (a) chronic phase after failure of IFN-alpha therapy, (b) accelerated phase, and (c) blast crisis. The accelerated approval was accompanied by a postmarketing commitment by Novartis Pharmaceuticals to continue patient follow-up to determine duration of treatment response and survival. The present review, based on a safety and efficacy report submitted on December 20, 2002, summarizes data applicable to the conversion of these three CML indications to full approval status. RESULTS: Chronic phase CML: Five hundred thirty-two chronic phase CML patients who had not benefited from prior IFN therapy were treated at a starting imatinib mesylate dose of 400 mg p.o. qd; dose escalation to 800 mg p.o. qd was allowed. Patients had received a median of 14 months of IFN therapy at doses > or =25 million IU/wk and were all in late chronic phase, with a median time from diagnosis of 32 months. Median duration of imatinib mesylate treatment was 29 months, with 81% of patients treated for > or =24 months (maximum 31.5 months). Initial favorable treatment responses were sustained. An estimated 87.8% of patients who had a major cytogenetic response maintained their response 2 years after their initial response. After 2 years of treatment, an estimated 85.4% of patients were free of progression to accelerated phase or blast crisis, and the estimated overall survival was 90.8% (95% confidence interval, 88.3-93.2). Accelerated phase CML: Patients enrolled totaled 293: 235 with CML accelerated phase, 48 with relapsed/refractory acute lymphocytic leukemia, 2 with relapsed/refractory acute myelocytic leukemia, and 8 with relapsed/refractory CML in lymphoid blast crisis. Patients received imatinib mesylate 400 or 600 mg p.o. qd. Dose escalation was permitted, to a maximum of 800 mg/d, taken as 400 mg bid. Efficacy results were improved in patients receiving imatinib mesylate 600 mg qd versus patients receiving 400 mg qd. The median duration of hematologic response was 29 versus 17 months and the estimated 24-month maintained hematologic response rate was 61% versus 42%. The median survival of patients treated with imatinib mesylate 600 mg qd was not reached versus 20.9 months for patients receiving 400 mg qd. Estimated 24-month survival rate was 66% versus 46%. The median survival in the advanced leukemia population (acute lymphocytic leukemia, acute myelocytic leukemia, and lymphoid blast crisis) was only 5 months, and only two patients are still on treatment. Blast crisis CML: A total of 260 patients were recruited. The imatinib mesylate dose was initially 400 mg qd (37 patients) but was subsequently increased to 600 mg qd (223 patients). Patients receiving imatinib mesylate 600 mg qd had a higher hematologic response rate than did patients receiving 400 mg (33% versus 16%). Major cytogenetic responses occurred in 15% of the 260 study patients. The overall median survival was 6.9 months: 7.1 months for patients treated with imatinib mesylate 600 mg and 4.7 months for patients receiving imatinib mesylate 400 mg. Estimated 12-month survival rate for all study patients was 32.1% and estimated 24-month survival rate was 18.3%. Safety: Imatinib mesylate was generally well tolerated, but relatively frequent reports of common toxicity criteria grade 3/4 neutropenia and thrombocytopenia were encountered. The most frequently reported adverse events included gastrointestinal disturbances, edema, rash, and musculoskeletal complaints. These rarely led to discontinuation of therapy. CONCLUSIONS: The results confirm those of the interim analysis and suggest that imatinib mesylate represents an effective therapeutic agent for the treatment of patients with CML in chronic phase after failure of IFN-alpha therapy, in blast crisis, and in accelerated phase.     

Phase 1 trial of irinotecan plus BCNU in patients with progressive or recurrent malignant glioma

Irinotecan is a topoisomerase I inhibitor previously shown to be active in the treatment of malignant glioma. We now report the results of a phase 1 trial of irinotecan plus BCNU, or 1,3-bis(2-chloroethyl)-1-nitrosourea, for patients with recurrent or progressive MG. Irinotecan dose escalation occurred independently within 2 strata: patients receiving enzyme-inducing antiepileptic drugs (EIAEDs) and patients not receiving EIAEDs. BCNU was administered at a dose of 100 mg/m2 over 1 h every 6 weeks on the same day as the first irinotecan dose was administered. Irinotecan was administered intravenously over 90 min once weekly. Treatment cycles consisted of 4 weekly administrations of irinotecan followed by a 2-week rest with dose escalation in cohorts of 3 to 6 patients. Seventy-three patients were treated, including 49 patients who were on EIAEDs and 24 who were not on EIAEDs. The maximum tolerated dose for patients not on EIAEDs was 125 mg/m2. The maximum tolerated dose for patients on EIAEDs was 225 mg/m2. Dose-limiting toxicity was evenly distributed among the following organ systems: pulmonary, gastrointestinal, cardiovascular, neurologic, infectious, and hematologic, without a clear predominance of toxicity involving any one organ system. There was no evidence of increasing incidence of toxicity involving one organ system as irinotecan dose was escalated. On the basis of these results, we conclude that the recommended doses of irinotecan for a phase 2 clinical trial when given in combination with BCNU (100 mg/m2) are 225 mg/m2 for patients on EIAEDs and 125 mg/m2 for patients not on EIAEDs.     

Phase I trial of tipifarnib in patients with recurrent malignant glioma taking enzyme-inducing antiepileptic drugs: a North American Brain Tumor Consortium Study.

PURPOSE: To determine the maximum-tolerated dose (MTD), toxicities, and clinical effect of tipifarnib, a farnesyltransferase (FTase) inhibitor, in patients with recurrent malignant glioma taking enzyme-inducing antiepileptic drugs (EIAEDs). This study compares the pharmacokinetics and pharmacodynamics of tipifarnib at MTD in patients on and off EIAEDs. PATIENTS AND METHODS: Recurrent malignant glioma patients were treated with tipifarnib using an interpatient dose-escalation scheme. Pharmacokinetics and pharmacodynamics were assessed. RESULTS: Twenty-three assessable patients taking EIAEDs received tipifarnib in escalating doses from 300 to 700 mg bid for 21 of 28 days. The dose-limiting toxicity was rash, and the MTD was 600 mg bid. There were significant differences in pharmacokinetic parameters at 300 mg bid between patients on and not on EIAEDs. When patients on EIAEDs and not on EIAEDs were treated at MTD (600 and 300 mg bid, respectively), the area under the plasma concentration-time curve (AUC)(0-12 hours) was approximately two-fold lower in patients on EIAEDs. Farnesyltransferase inhibition was noted at all tipifarnib dose levels, as measured in peripheral-blood mononuclear cells (PBMC). CONCLUSION: Toxicities and pharmacokinetics differ significantly when comparing patients on or off EIAEDs. EIAEDs significantly decreased the maximum concentration, AUC(0-12 hours), and predose trough concentrations of tipifarnib. Even in the presence of EIAEDs, the levels of tipifarnib were still sufficient to potently inhibit FTase activity in patient PBMCs. The relevance of these important findings to clinical activity will be determined in ongoing studies with larger numbers of patients.     

A phase I trial to determine the safety of imatinib in combination with vatalanib in patients with advanced malignancies

The role of tyrosine kinase inhibitors (TKIs) in the treatment of advanced malignancies is well established. Imatinib and vatalanib are oral TKIs with different mechanisms of action. This trial sought to establish the safety, tolerability, and maximum tolerated dose (MTD) of the two agents in combination. Secondary objectives included determination of potential pharmacologic interactions among vatalanib and imatinib and observation of antitumor activity. Patients with biopsy-proven advanced refractory solid tumors were enrolled in this single-center dose-escalation trial. Patients initially received imatinib and vatalanib once daily following a 14-day run-in period of daily oral vatalanib only, and were observed for a full 28-day treatment cycle prior to dose escalation. An amendment divided the vatalanib dose into two daily doses and gradually escalated the dose over a 2-3 week period. Patients continued combination therapy until disease progression or intolerable toxicity. Forty-five patients were enrolled between September 2004 and November 2007. As of September 2009, a total of 247 cycles of treatment had been administered (range: 1 -44+, median = 2 ). The MTD was determined to be vatalanib 1250 mg daily and imatinib 400 mg daily. Thirty-five patients (78%) were evaluable for response; 2 patients achieved PR, while 14 patients had SD ( 10 had stable disease ≥ 6 cycles). The combination of vatalanib and imatinib was well tolerated. Twice-daily vatalanib dosing improved tolerability and ease of full-dose administration. These results suggest that vatalanib-containing combinations may be active and tolerable, warranting further study.     

Pharmacokinetics and pharmacodynamics of imatinib in a phase I trial with chronic myeloid leukemia patients.

PURPOSE: To evaluate the basic pharmacokinetic (PK) characteristics of imatinib mesylate and assess the relationship between the PK and pharmacodynamic (PD) properties of the drug. PATIENTS AND METHODS: The PK and PD properties of imatinib were investigated during a phase I trial that included 64 adult patients with Philadelphia chromosome-positive leukemias. Patients received imatinib orally once or twice daily. PK parameters of imatinib, derived from the plasma concentration-time curves, were determined. PD response, defined as the WBC after 1 month of treatment with imatinib, was used to develop an efficacy model. A maximum inhibition-effect model was used to describe the relationship between reduction in WBC and drug exposure parameters. RESULTS: Imatinib exposure was dose proportional after oral administration for the dose range of 25 to 1,000 mg. There was a 1.5- to three-fold drug accumulation after repeated once-daily dosing. Mean plasma trough concentration was 0.57 microg/mL (approximately 1 micromol/L) 24 hours after administration of 350 mg of imatinib at steady-state, which exceeds the 50% inhibitory concentration required to inhibit proliferation of Bcr-Abl-positive leukemic cells. Analysis of PK/PD relationships indicates that the initial hematologic response depends on the administered dose for patients with chronic myeloid leukemia. CONCLUSION: Drug exposure (area under the concentration-time curve) is dose proportional for the dose range of 25 to 1,000 mg, and there is a 1.5- to three-fold drug accumulation at steady-state after once-daily dosing. Analysis of the relationship between PD (WBC reduction) and PK parameters at steady-state indicates that a dose of 400 mg or greater is required for maximal PD effect.