AZD2281 and Irinotecan in Treating Patients With Locally Advanced or Metastatic Colorectal Cancer

OBJECTIVES: * To determine the recommended phase II dose of AZD2281 and irinotecan hydrochloride in patients with locally advanced or metastatic colorectal cancer. * To determine the safety, tolerability, toxicity profile, dose-limiting toxicities, and pharmacokinetic profile of this regimen. * To assess the correlation, if any, between the toxicity profile and pharmacokinetics of this regimen. * To assess, preliminarily, the antitumor activity of this regimen in patients with measurable disease. * To demonstrate the pharmacodynamic activity of this regimen by establishing its effects in tumor biopsies, cheek swabs, and blood samples. * To assess the correlation, if any, between patients with tumors demonstrating microsatellite instability and antitumor activity and pharmacodynamic effects of this regimen. * To investigate the impact of common genetic polymorphisms of genes of relevant pathways (drug metabolism, DNA repair, and apoptosis) on outcome and toxicity as well as other pharmacodynamic effects. OUTLINE: This is a multicenter, dose-escalation study of AZD2281 and irinotecan hydrochloride. * Part I: Patients receive oral AZD2281 twice a day on days -7 to 21 in course 1 and on days 1-21 in all subsequent courses. Patients also receive irinotecan hydrochloride IV over 90 minutes on day 1. Courses repeat every 21 days (course 1 is 28 days) until the maximum tolerated dose is determined in the absence of disease progression or unacceptable toxicity. * Part II: Patients then receive oral AZD2281 once daily on days 1-5 and irinotecan hydrochloride IV over 90 minutes on day 3 at the maximum tolerated dose determined in Part I. Courses repeat every 14 days in the absence of disease progression or unacceptable toxicity. Patients undergo cheek swabs, tumor tissue, and blood sample collection periodically for pharmacokinetic, pharmacodynamic, and correlative studies. After completion of study treatment, patients are followed at 4 weeks and then every 3 months thereafter.