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

DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed colorectal cancer

  * Locally advanced and/or metastatic disease
  * Disease considered incurable
* Suitable for treatment with single agent irinotecan hydrochloride as a palliative intervention, as determined by the investigator
* Must have clinically and/or radiologically documented disease

  * Patients whose only evidence of disease progression is tumor marker elevation are not eligible
* Must have received no more than one prior oxaliplatin- and/or irinotecan hydrochloride-based chemotherapy regimen given either with adjuvant, neoadjuvant, or palliative intent

  * One additional adjuvant fluoropyrimidine (fluorouracil or capecitabine) regimen may have been given for relapsed or metastatic disease
* No untreated brain or meningeal metastases (CT scan required if there is a clinical suspicion of CNS disease)

PATIENT CHARACTERISTICS:

* ECOG performance status 0-2
* Absolute granulocyte count ≥ 1,500/mm³
* Platelet count ≥ 100,000/mm³
* Bilirubin ≤ 1.5 times upper limit of normal (ULN)
* ALT and AST ≤ 2 times ULN (≤ 5 times ULN if liver metastasis is present)
* Serum creatinine ≤ 1.5 x ULN OR creatinine clearance ≥ 50 mL/min
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception during and for 90 days after completion of study therapy
* Must reside within a 1½ hour drive from participating center
* No other invasive malignancies, unless curatively treated with no evidence of disease
* No GI tract disease resulting in an inability to absorb oral medication, including the following:

  * Uncontrolled inflammatory GI disease (e.g., Crohn's disease or ulcerative colitis)
  * Post-surgical malabsorption characterized by uncontrolled diarrhea that results in weight loss and vitamin deficiency or requires IV hyperalimentation

    * Pancreatic enzyme supplementation is allowed
* No untreated and/or uncontrolled hypertension, cardiovascular conditions, and/or symptomatic cardiac dysfunction
* No active or uncontrolled infections
* No serious illnesses or medical conditions that would preclude study participation
* No known hypersensitivity to the study drugs or their components, atropine, or loperamide
* Not known to be homozygous for the UGT1A1\*28 allele
* No known deficiency in glucuronidation of bilirubin, such as Gilbert's syndrome
* No neuropathy ≥ grade 2

  * Patients with persistent, stable, grade 3 sensory neuropathy, who meet other eligibility criteria may be allowed at the discretion of the investigator

PRIOR CONCURRENT THERAPY:

* Recovered from all prior therapy
* No prior PARP inhibitor
* No prior radical pelvic irradiation
* No prior radiotherapy to ≥ 25% of bone marrow stores
* Prior irinotecan hydrochloride allowed provided the drug was not discontinued due to toxic effects and the patient did not have severe irinotecan hydrochloride-related toxicity (grade 4 or requiring hospitalization)
* At least 21 days since prior radiotherapy (exceptions may be made for low-dose, nonmyelosuppressive radiotherapy)
* At least 30 days since prior chemotherapy
* At least 21 days since prior hormonal, immunologic, biologic, or signal transduction inhibitor therapies
* More than 3 weeks since prior and no other concurrent investigational drugs or anticancer therapy
* At least 14 days since prior major surgery

  * Wound healing must have occurred
* At least 14 days since prior and no concurrent CYP3A4 enzyme-inducing or -inhibiting drugs, including enzyme-inducing anticonvulsants, rifampin, rifabutin, St. John's wort, atazanavir, or ketoconazole

  * Dexamethasone is allowed for antiemetic prophylaxis