RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining bone marrow or peripheral stem cell transplantation with chemotherapy may allow the doctor to give higher doses of chemotherapy drugs and kill more cancer cells. Interferon alfa may interfere with the growth of cancer cells. It is not yet known whether a more intensive chemotherapy regimen plus stem cell or bone marrow transplant is more effective than standard chemotherapy in treating patients with myeloma.