Bryostatin 1 in Treating Patients With Stage IV Breast Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die.

PURPOSE: Phase II trial to study the effectiveness of bryostatin 1 in treating patients with stage IV breast cancer.

OBJECTIVES:

* Determine the clinical response of patients with stage IV breast cancer to bryostatin 1.
* Determine the efficacy of this regimen in these patients.
* Estimate the pharmacokinetic parameters of bryostatin 1 when given as 24 hour infusion.
* Determine the ability of this regimen to regulate lymphocyte function in these patients.
* Determine the effect of this regimen on platelet function and protein kinase C activity in these patients.

OUTLINE: Patients receive bryostatin 1 IV over 24 hours. Treatment continues weekly in the absence of disease progression or unacceptable toxicity.

Patients are followed every 4-8 weeks for tumor response.

PROJECTED ACCRUAL: A total of 14-25 patients will be accrued for this study.

Eligibility Criteria:
DISEASE CHARACTERISTICS:

* Unequivocal diagnosis of metastatic breast cancer
* Bidimensionally measurable disease
* No uncontrolled CNS metastases
* No disease that is evaluable only, including blastic bone disease, malignant ascites, and malignant pleural effusion
* Hormone receptor status:

  * Not specified

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Menopausal status:

* Not specified

Performance status:

* SWOG 0-2 OR
* Karnofsky 60-100%

Life expectancy:

* At least 18 weeks

Hematopoietic:

* Platelet count at least 50,000/mm\^3
* PT and PTT within normal limits
* Neutrophil count at least 2,000/mm\^3

Hepatic:

* Bilirubin no greater than 1.2 mg/dL
* Transaminases no greater than 3 times normal

Renal:

* Creatinine no greater than 1.6 mg/dL OR
* Creatinine clearance at least 70 mL/min

Other:

* No active infections requiring antibiotics
* No viral hepatitis allowed
* Seronegative for hepatitis B or C
* Not pregnant or nursing
* Fertile patients must use effective contraception during and for 2 months following study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* No concurrent immunotherapy

Chemotherapy:

* 2 prior chemotherapy regimens for metastatic disease allowed as adjuvant therapy or for advanced disease (may include high dose chemotherapy with stem cell support)
* At least 4 weeks since prior chemotherapy
* At least 6 weeks since prior nitrosourea or mitomycin therapy
* No other concurrent chemotherapy

Endocrine therapy:

* 2 prior hormonal therapy regimens for metastatic disease as adjuvant therapy or for advanced diseases allowed
* At least 2 weeks since prior hormonal therapy (at least 4 weeks in case of disease progression while receiving hormonal therapy after initial response)
* No concurrent hormonal therapy except oral contraceptives
* No concurrent use of steroids except for management of severe or life- threatening toxic effects arising from bryostatin 1

Radiotherapy:

* At least 2 weeks since prior radiotherapy
* No concurrent radiotherapy

Surgery:

* Not specified

Other:

* No concurrent use of drugs known to interfere with platelet function, such as aspirin or NSAIDs (including ibuprofen)
* No concurrent use of anticoagulants
* At least 2 weeks since prior use of aspirin
* At least 2 days since prior use of NSAIDS
* Concurrent use of acetaminophen to control pain is allowed
* If acetaminophen inadequate for pain control, concurrent use of oral narcotics such as codeine or oxycodone is allowed