Study was closed at the suggestion of DSMB prior to obtaining target enrollment

RATIONALE: Drugs used in chemotherapy, such as pentamidine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing.

PURPOSE: This phase II trial is studying how well pentamidine works in treating patients with relapsed or refractory melanoma.

OBJECTIVES:

Primary

• To determine the response rate in patients with relapsed or refractory melanoma that expresses wild-type p53 and S100 calcium binding protein B (S100B) treated with pentamidine.

Secondary

• To observe the effect of this drug on the expression of S100B and p21 in tumor biopsy samples.
• To observe the effect of this drug on S100B detectable in serum.
• To observe the time to progression in these patients.
• To assess the toxicities associated with the administration of this drug in these patients.

OUTLINE: Patients receive pentamidine IV over 2 hours 5 days a week for 2 weeks. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.

Patients undergo tumor tissue and blood sample collection periodically for correlative laboratory studies. Samples are assessed for p53 status and S100B, p53, and p21 expression by immunohistochemistry, polymerase chain reaction, western blotting, luminescence assay, and ELISA.

After completion of study treatment, patients are followed for 30 days.

DISEASE CHARACTERISTICS:

• Histologically confirmed melanoma

  • Relapsed or refractory disease

• Tumor expresses wild-type p53

• Measurable S100B by immunohistochemistry

• Measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded) as ≥ 20 mm by conventional techniques or as ≥ 10 mm by spiral CT scan

• Tumor amenable to biopsy

• Must have been evaluated for potentially curative resection

• No unstable or symptomatic brain metastases (e.g., seizures, headache related to tumor, or presence of neurologic deficits attributable to tumor)

  • Patients with stable brain metastases (by CT scan or MRI) are eligible provided they were treated with local therapy > 4 weeks ago AND do not require maintenance steroid treatment

PATIENT CHARACTERISTICS:

• Eastern Cooperative Oncology Group (ECOG) performance status 0-2

• Life expectancy > 12 weeks

• White Blood Cell count (WBC) ≥ 3,000/mcL

• Absolute Neutrophil Count (ANC) ≥ 1,500/mcL

• Platelet count ≥ 80,000/mcL

• Hemoglobin ≥ 8 g/dL

• Total bilirubin ≤ 1.5 times normal

• aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 times upper limit of normal

• Creatinine ≤ 1.5 times normal or creatinine clearance ≥ 60 mL/min

• Not pregnant or nursing

• Fertile patients must use effective contraception during and for ≥ 3 months after completion of study treatment

• Able to take oral medications on a regular basis

• No history of allergic reactions attributed to pentamidine

• Mean Corrected QT Interval (QTc) ≤ 470 msec (with Bazett's correction) on screening ECG

• No history of familial long QT syndrome

• Proteinuria ≤ 1 on two consecutive dipsticks taken ≥ 1 week apart

• No concurrent uncontrolled illness including, but not limited to, any of the following:

  • Hypertension
  • Ongoing or active infection
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Renal failure
  • Cardiac arrhythmia
  • Psychiatric illness/social situations that would limit compliance with study requirements

PRIOR CONCURRENT THERAPY:

• Recovered from all prior therapy
• Any number of prior chemotherapy regimens allowed
• More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C)
• More than 4 weeks since prior radiotherapy or major surgery
• More than 30 days since prior participation in an investigational trial
• No concurrent medication that may markedly affect renal function (e.g., vancomycin, amphotericin, zoledronic acid)
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No other concurrent investigational agents

Unable to reach the target number of participants needed before study was closed at the suggestion of DSMB