RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Combining more than one drug may kill more cancer cells.

PURPOSE: This phase I trial is studying the side effects and best dose of bryostatin-1 when given together with vincristine in treating patients with chronic lymphocytic leukemia, non-Hodgkin's lymphoma, or multiple myeloma.

OBJECTIVES: I. Determine the maximum tolerated dose of bryostatin 1 when combined with vincristine in patients with B-cell malignancies. II. Assess clinical responses in patients treated with this regimen.

OUTLINE: This is a dose-escalation study of bryostatin 1. Patients receive bryostatin 1 IV over 24 hours followed immediately by vincristine IV. Treatment repeats every 2 weeks in the absence of disease progression or unacceptable toxicity. Patients completing 6 courses of therapy may receive subsequent courses every 3 weeks and then every 4 weeks after 24 months of treatment. Patients may return to a 2- or 3-week treatment course at the discretion of the principal investigator. Cohorts of 3 patients receive escalating doses of bryostatin 1 until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which at least 1 of 3 patients experience dose-limiting toxicity. Patients are followed every 3 months.

PROJECTED ACCRUAL: Approximately 18 patients will be accrued for this study within 12-15 months.

• Leukemia
• Lymphoma
• Multiple Myeloma and Plasma Cell Neoplasm

• Drug: bryostatin 1
• Drug: vincristine sulfate

DISEASE CHARACTERISTICS: Histologically proven B-cell malignancies (e.g., chronic lymphocytic leukemia (CLL), non-Hodgkin's lymphoma (NHL), or multiple myeloma (MM)) Specific requirements for each disease: CLL patients must have failed prior chemotherapy with fludarabine and an alkylating agent Aggressive NHL patients must have failed all other possible curative therapies MM patients must have had at least 1 prior chemotherapy regimen and not be eligible for dose intensification treatment approach No brain metastasis or leptomeningeal involvement No primary CNS NHL, HIV-associated lymphoma, or acute leukemia

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: WBC at least 3,000/mm3 Granulocyte count at least 1,500/mm3 Platelet count at least 50,000/mm3 Hemoglobin greater than 8.5 g/dL Hepatic: Bilirubin no greater than 1.5 mg/dL AST and ALT no greater than 2 times normal No evidence of bleeding diathesis Renal: Creatinine no greater than 2.0 mg/dL OR Creatinine clearance at least 40 mL/min Neurologic: No clinically apparent neuropathy (grade 2 or greater neuropathy) Other: HIV negative Not pregnant or nursing Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics At least 3 weeks since prior chemotherapy (6 weeks for carmustine and mitomycin) and recovered Prior vincristine allowed Endocrine therapy: No concurrent steroids Radiotherapy: At least 4 weeks since prior large-field radiotherapy Surgery: Not specified