Dataset Information

The impact of bevacizumab on temozolomide concentrations in intracranial U87 gliomas.

ABSTRACT: An important question in the sequencing of anti-cancer therapies in patients with glioblastoma (GBM) is whether concurrent anti-angiogenesis therapies improve or impair brain concentrations of concomitantly administered cytotoxic therapies. The purpose of this study is to assess the intratumoral disposition of temozolomide (TMZ) via microdialysis before and after bevacizumab in an intracranial GBM xenograft model.Microdialysis probes were placed within tumor and contralateral brain in athymic rats bearing U87 intracerebral gliomas. TMZ (50 mg/kg oral) was administered 10 days thereafter. Extracellular fluid (ECF) was collected for 6 h. BEV was administered (10 mg/kg IV), and TMZ was re-dosed (50 mg/kg oral) 36 h thereafter with additional ECF collection. All ECF samples were assessed for TMZ concentration with liquid chromatography-tandem mass spectrometry.Tumor TMZ mean area under the concentration-time curve (AUC(0-?)) was 3.35 ?g h/mL pre-BEV. Post-BEV, tumor mean TMZ AUC(0-?) was 3.98 ?g h/mL. In non-tumor brain, mean TMZ AUC(0-?) pre-BEV was 3.22 ?g h/mL and post-BEV was 3.34 ?g h/mL.There were no statistically significant changes in TMZ pharmacokinetics before or after BEV in the athymic rat U87 intracranial glioma model. BEV and TMZ are being investigated as a combination therapy in several ongoing studies for patients with glioma. These data reassuringly suggest that BEV does not significantly change the ECF tumor concentrations of TMZ in either tumor-bearing or normal brain when dosed 36 h prior to TMZ.

SUBMITTER: Grossman R

PROVIDER: S-EPMC4005329 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The impact of bevacizumab on temozolomide concentrations in intracranial U87 gliomas.

Grossman Rachel R Rudek Michelle A MA Brastianos Harry H Zadnik Patti P Brem Henry H Tyler Betty B Blakeley Jaishri O JO

Cancer chemotherapy and pharmacology 20120527 1

<h4>Purpose</h4>An important question in the sequencing of anti-cancer therapies in patients with glioblastoma (GBM) is whether concurrent anti-angiogenesis therapies improve or impair brain concentrations of concomitantly administered cytotoxic therapies. The purpose of this study is to assess the intratumoral disposition of temozolomide (TMZ) via microdialysis before and after bevacizumab in an intracranial GBM xenograft model.<h4>Methods</h4>Microdialysis probes were placed within tumor and c ...[more]

PMID: 22644796

Similar Datasets

Project description:The prognosis for patients with glioblastoma (GB) remains grim. Concurrent temozolomide (TMZ) radiation-the cornerstone of glioma control-extends the overall median survival of GB patients by only a few months over radiotherapy alone. While these survival gains could be partly attributed to radiosensitization, this benefit is greatly minimized in tumors expressing O6-methylguanine DNA methyltransferase (MGMT), which specifically reverses O6-methylguanine lesions. Theoretically, non-O6-methylguanine lesions (i.e., the N-methylpurine adducts), which represent up to 90% of TMZ-generated DNA adducts, could also contribute to radiosensitization. Unfortunately, at concentrations attainable in clinical practice, the alkylation capacity of TMZ cannot overwhelm the repair of N-methylpurine adducts to efficiently exploit these lesions. The current therapeutic application of TMZ therefore faces two main obstacles: (i) the stochastic presence of MGMT and (ii) a blunted radiosensitization potential at physiologic concentrations. To circumvent these limitations, we are developing a novel molecule called NEO212-a derivatization of TMZ generated by coupling TMZ to perillyl alcohol. Based on gas chromatography/mass spectrometry and high-performance liquid chromatography analyses, we determined that NEO212 had greater tumor cell uptake than TMZ. In mouse models, NEO212 was more efficient than TMZ at crossing the blood-brain barrier, preferentially accumulating in tumoral over normal brain tissue. Moreover, in vitro analyses with GB cell lines, including TMZ-resistant isogenic variants, revealed more potent cytotoxic and radiosensitizing activities for NEO212 at physiologic concentrations. Mechanistically, these advantages of NEO212 over TMZ could be attributed to its enhanced tumor uptake presumably leading to more extensive DNA alkylation at equivalent dosages which, ultimately, allows for N-methylpurine lesions to be better exploited for radiosensitization. This effect cannot be achieved with TMZ at clinically relevant concentrations and is independent of MGMT. Our findings establish NEO212 as a superior radiosensitizer and a potentially better alternative to TMZ for newly diagnosed GB patients, irrespective of their MGMT status.

Dataset Information

The impact of bevacizumab on temozolomide concentrations in intracranial U87 gliomas.

Publications

The impact of bevacizumab on temozolomide concentrations in intracranial U87 gliomas.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets