RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining chemotherapy with peripheral stem cell transplantation may allow the doctor to give higher doses of chemotherapy drugs and kill more tumor cells. Interleukin-2 may stimulate a person's white blood cells to kill multiple myeloma cells. Interferon alfa may interfere with the growth of cancer cells.

PURPOSE: Phase II trial to study the effectiveness of melphalan, peripheral stem cell transplantation, and interleukin-2 followed by interferon alfa in treating patients who have advanced multiple myeloma.

OBJECTIVES:

• Determine initial response to therapy, time to disease progression, and overall survival of patients with advanced multiple myeloma treated with autologous or syngeneic peripheral blood stem cell transplantation, melphalan, and interleukin-2 followed by interferon alfa.
• Compare the toxic effects encountered by patients under age 56 (closed to accrual as of 9/1/03) vs patients age 56 and over treated with this regimen.

OUTLINE: Patients are stratified according to age (18 to 55 [closed to accrual as of 9/1/03] vs 56 and over).

Patients receive melphalan IV over 2-3 hours on day -2 and an infusion of interleukin-2 (IL-2)-treated autologous or syngeneic peripheral blood stem cells on day 0. Beginning on day 0, patients also receive IL-2 IV continuously over 5 days. Treatment with IL-2 repeats weekly for 4 weeks.

Maintenance therapy begins 1 month after IL-2 treatment. Patients receive interferon alfa subcutaneously 3 times a week in the absence of disease progression or unacceptable toxicity.

Patients are followed every 3 months for 3 years and then annually thereafter.

PROJECTED ACCRUAL: A total of 40 patients (20 per stratum) (age 18 to 55 stratum closed to accrual as of 9/1/03) will be accrued for this study within 3 years.

• Biological: aldesleukin
• Biological: recombinant interferon alfa
• Drug: melphalan
• Procedure: in vitro-treated peripheral blood stem cell transplantation

DISEASE CHARACTERISTICS:

• Diagnosis of advanced multiple myeloma meeting 1 of the following staging criteria:

  • Diagnosis of stage II or III disease initially
  • Stage I disease refractory to or progressed after initial therapy

• Meets 1 of the following criteria:

  • Has an identical syngeneic twin
  • Meets eligibility requirements for mobilization/debulking with cyclophosphamide/etoposide/filgrastim (G-CSF), cyclophosphamide/G-CSF, or cyclophosphamide/paclitaxel/G-CSF (protocol FHCRC-506STP)
• No pleural or pericardial effusion or ascites

PATIENT CHARACTERISTICS:

Age:

• 18 to 69 (age 18 to 55 stratum closed to accrual as of 9/1/03)

Performance status:

• Karnofsky 80-100%

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Bilirubin no greater than 1.5 mg/dL (unless there is a history of Gilbert's disease)
• SGOT or SGPT no greater than 2 times upper limit of normal
• Hepatitis C or B negative

Renal:

• Creatinine no greater than 2.0 mg/dL OR
• Creatinine clearance at least 60 mL/min

Cardiovascular:

• LVEF at least 50%
• No congestive heart disease
• No prior myocardial infarction
• No coronary artery disease
• No prior arrhythmia

Pulmonary:

• DLCO at least 60%
• FEV1 at least 65% of predicted

Other:

• No other malignancies within the past 5 years except basal cell skin cancer or carcinoma in situ
• No history of seizures
• No active connective tissue disease
• No allergy to gentamicin
• No hypersensitivity to E. coli-derived preparations
• No systemic infection
• Not pregnant or nursing
• Fertile patients must use effective contraception
• HIV negative

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent growth factors

Chemotherapy:

• See Disease Characteristics
• At least 30 days since prior chemotherapy

Endocrine therapy:

• No concurrent corticosteroids

Radiotherapy:

• Not specified

Surgery:

• Not specified

Other:

• No concurrent medications (e.g., haloperidol) for controlling mental disorders
• No contrast dyes during and for 3 weeks after study participation