Pharmacokinetics in Patients With Newly Diagnosed High-Grade Glioma Receiving Temozolomide and Radiation Therapy

OBJECTIVES:

- Compare the pharmacokinetic (PK) profiles of temozolomide (TMZ) in patients who develop
severe thrombocytopenia vs PK profiles in patients who do not develop severe
thrombocytopenia while receiving standard first-line therapy for management of newly
diagnosed high-grade gliomas.

- Determine if patients who develop thrombocytopenia have any single nucleotide
polymorphisms in the O6-methylguanine-DNA methyltransferase gene.

OUTLINE: This is a pilot, prospective, multicenter study.

Patients receive oral temozolomide once daily on days 1-42. Patients also undergo cranial
radiotherapy 5 days a week for 6 weeks in the absence of disease progression or unacceptable
toxicity.

Blood samples are collected periodically for pharmacokinetic and pharmacogenomic analysis,
genotype analysis, plasma temozolomide levels, and MGMT repair gene polymorphism analysis.

After completion of study treatment, patients are followed for 1 month.

PROJECTED ACCRUAL: A total of 150 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

- Histologically confirmed high-grade glioma (WHO grade III or IV)

- Must be scheduled to receive standard first-line therapy (cranial radiotherapy and
temozolomide)

PATIENT CHARACTERISTICS:

- ANC ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Creatinine ≤ 1.7 mg/dL

- Bilirubin ≤ 1.5 mg/dL

- Transaminases ≤ 4 times upper limit of normal

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No other malignancy within the past 5 years except curatively treated carcinoma in
situ or basal cell carcinoma of the skin

PRIOR CONCURRENT THERAPY:

- No prior hormonal therapy for brain tumor

- No prior biological agents (including immunotoxins, immunoconjugates, antisense
agents, peptide receptor antagonists, interferons, interleukins, tumor-infiltrating
lymphocytes, lymphokine-activated killer cells, or gene therapy)

- No prior immunotherapy

- No prior chemotherapy

- No prior radiotherapy, including cranial radiotherapy

- Concurrent glucocorticoid therapy allowed

- No concurrent carbamazepine

- No other concurrent experimental therapy

- No other concurrent cytotoxic therapy