Rosiglitazone in Treating Patients With Pituitary Tumors

OBJECTIVES:

* To assess the effect of rosiglitazone maleate on the core biochemical parameter, 24-hour urinary free cortisol levels, in patients with recurrent or uncured pituitary-dependent Cushing disease. (Group 1) * To assess the effect of this drug on corticotropin-releasing hormone-stimulated pituitary tumor ACTH secretion in patients with recurrent or uncured pituitary-dependent Cushing disease. (Group 1) * To assess the effect of this drug on tumor growth in patients with non-secreting pituitary macroadenoma (\> 10 mm) using RECIST criteria. (Group 2) * To assess the effect of this drug on pituitary tumor gonadotropin (i.e., follicle-stimulating hormone, leuteinizing hormone, and alpha-subunit) secretion in patients with non-secreting macroadenoma. (Group 2) * To assess the overall safety and tolerability of this drug in both cohorts of patients. * To assess the overall quality of life, in terms of performance status during treatment, of both cohorts of patients using the Karnofsky performance index.

OUTLINE: Patients are grouped according to adrenocorticotropic hormone (ACTH)-secreting status (yes \[Group 1\] vs no \[Group 2\]).

* Group 1 (ACTH-secreting adenomas): Patients receive 4 mg oral rosiglitazone maleate once daily in week 1 and then 8 mg once daily beginning in week 2 and continuing for up to 6 months in the absence of disease progression or unacceptable toxicity. * Group 2 (non-secreting macroadenomas): Patients receive 4 mg oral rosiglitazone maleate once daily in week 1 and then 8 mg once daily beginning in week 2 and continuing for up to 12 months in the absence of disease progression or unacceptable toxicity.

Patients undergo collection of blood and urine samples at baseline and after completion of study therapy to assess pituitary function, thyroid function, and 24-hour urinary free cortisol levels. Additional assessments include corticotrophin-stimulation testing, dynamic pituitary function testing (i.e., arginine/growth-hormone releasing-hormone testing) to measure growth hormone secretion, and overnight 1 mg dexamethasone suppression testing to measure 8 a.m. serum cortisol levels. Patients also undergo MRI at baseline and after completion of study therapy to examine the effects of rosiglitazone maleate treatment on pituitary tumor size.

Patients complete a questionnaire at baseline and monthly during study for evaluation of headaches.

PROJECTED ACCRUAL: A total of 15 patients with ACTH-secreting pituitary tumor and 15 patients with non-secreting pituitary macroadenomas will be accrued for this study.