RATIONALE: Giving antibiotics may be effective in preventing or controlling early infection in patients with multiple myeloma and may improve their response to chemotherapy.

PURPOSE: This randomized clinical trial is studying antibiotics to see how well they work compared to no antibiotics in preventing early infection in patients with multiple myeloma.

OBJECTIVES:

• Evaluate whether oral antibiotic prophylaxis with co-trimoxazole (TMP-SMX) versus ciprofloxacin (CPFX) or ofloxacin versus no prophylaxis will significantly reduce rates of serious bacterial infections during the first 3 months of chemotherapy in patients with multiple myeloma.
• Determine whether antibiotic prophylaxis with TMP-SMX or CPFX (or ofloxacin) is associated with an increased incidence of nonbacterial infection or an increased rate of infection from organisms resistant to prophylactic antibiotics.
• Evaluate whether oral antibiotic prophylaxis with CPFX or ofloxacin is as effective as TMP-SMX without the associated toxic effects.
• Evaluate whether protection against early infection in multiple myeloma patients can improve their response to initial chemotherapy.

OUTLINE: This is a randomized, multicenter study. Patients are stratified by participating center. Patients are randomized to 1 of 3 treatment arms.

• Arm I: Patients receive co-trimoxazole every 12 hours for 2 months followed by observation for 2 months.
• Arm II: Patients receive oral ciprofloxacin or ofloxacin every 12 hours for 2 months followed by observation for 1 month.
• Arm III: Patients receive no prophylactic antibiotics and are observed for 3 months.

Patients continue their randomly assigned treatment throughout any infection in addition to any treatment needed for infection. Patients also remain on their randomly assigned treatment if chemotherapy is discontinued, changed, or delayed during the 3 month study.

Patients are followed at 6 months, 1 year, and 2 years.

PROJECTED ACCRUAL: A total of 210 patients (70 per treatment arm) will be accrued for this study.

• Infection
• Multiple Myeloma and Plasma Cell Neoplasm

• Drug: ciprofloxacin
• Drug: ofloxacin
• Drug: trimethoprim-sulfamethoxazole

DISEASE CHARACTERISTICS:

• Diagnosis of multiple myeloma (MM) based on one of the following:

  • Bone marrow plasmacytosis with at least 10% abnormal plasma cells
  • Multiple biopsy-proven plasmacytomas

• At least 1 of the following required:

  • Myeloma protein in serum
  • Myeloma protein in urine, i.e., free monoclonal light chain

  • Radiologic evidence of osteolytic lesions

    • Generalized osteoporosis qualifies only if bone marrow aspirate contains at least 20% plasma cells
• No smoldering myeloma

• Planning to initiate 1 of the following regimens as primary therapy for MM within 3 days of study entry:

  • Myelosuppressive chemotherapy
  • High-dose dexamethasone
  • Dexamethasone and thalidomide

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Creatinine less than 5.0 mg/dL

• No requirement for dialysis at study entry

  • If required after entry, patients continue study with adjusted medication guidelines

Other:

• Not pregnant
• No history of hypersensitivity to fluoroquinolones or trimethoprim
• At least 7 days since prior active infection

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• See Disease Characteristics
• No bone marrow transplant or autologous stem cell rescue planned within first 2 months of myeloma chemotherapy
• No concurrent prophylactic filgrastim (G-CSF) during the first 2 months of study participation
• No concurrent intravenous immunoglobulins

Chemotherapy:

• See Disease Characteristics
• No prior chemotherapy (except mithramycin)

Endocrine therapy:

• See Disease Characteristics
• Prior corticosteroids allowed
• No prior high-dose dexamethasone

Radiotherapy:

• At least 10 days since prior radiotherapy
• No radiotherapy planned for near future

Surgery:

• Not specified

Other:

• At least 7 days since prior antibiotics
• No concurrent theophylline
• No concurrent sucralfate or oral antacids if receive ciprofloxacin or ofloxacin

• National Cancer Institute (NCI)
• Eastern Cooperative Oncology Group