DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed adenocarcinoma of the pancreas

* Locally advanced or metastatic disease
* Unidimensionally measurable disease

* At least 1 lesion that is at least 20 mm with conventional techniques or at least 10 mm with spiral CT scan
* Must have progressed after chemotherapy with a gemcitabine-containing regimen
* No known brain metastases

PATIENT CHARACTERISTICS:

Age

* Over 18

Performance status

* ECOG 0-1

Life expectancy

* Not specified

Hematopoietic

* WBC at least 3,000/mm\^3
* Absolute neutrophil count at least 1,500/mm\^3
* Platelet count at least 100,000/mm\^3

Hepatic

* Bilirubin no greater than 1.5 mg/dL
* AST/ALT no greater than 5 times upper limit of normal

Renal

* Creatinine no greater than 1.5 mg/dL OR
* Creatinine clearance at least 60 mL/min

Cardiovascular

* QTc less than 500 msec at baseline by EKG
* No New York Heart Association class III or IV heart failure
* No symptomatic congestive heart failure
* No unstable angina pectoris
* No cardiac arrhythmia

Other

* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No prior allergic reactions attributed to compounds of similar chemical or biological composition to arsenic trioxide
* No other active malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix
* No ongoing or active infection
* No psychiatric illness or social situation that would preclude study compliance
* No other uncontrolled illness

PRIOR CONCURRENT THERAPY:

Biologic therapy

* No concurrent immunotherapy
* No concurrent colony-stimulating factors during the first course of the study

Chemotherapy

* See Disease Characteristics
* At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered
* No prior arsenic trioxide
* No other concurrent chemotherapy
* No more than 1 prior chemotherapy regimen for metastatic disease

Endocrine therapy

* No concurrent hormonal therapy

Radiotherapy

* At least 4 weeks since prior radiotherapy and recovered
* No concurrent therapeutic radiotherapy

Surgery

* At least 4 weeks since major surgery

Other

* No other concurrent investigational or commercial anticancer agents or therapies
* No other concurrent investigational agents
* No concurrent antiretroviral therapy in HIV-positive patients
* No concurrent medications for other comorbid conditions that are known to prolong the QT interval