Rituximab, Yttrium Y 90 Ibritumomab Tiuxetan, Melphalan, and Autologous Peripheral Stem Cell Transplant in Treating Patients With Previously Treated Multiple Myeloma

DISEASE CHARACTERISTICS:

* Diagnosis of multiple myeloma

  * Previously treated disease
* Candidate for high-dose chemotherapy with melphalan and autologous stem cell transplantation
* No definite evidence of myelodysplasia on pretreatment bone marrow by morphology or by chromosome analysis (e.g., monosomy 7)

  * Chromosome abnormalities from the myeloma clone allowed

PATIENT CHARACTERISTICS:

* ECOG performance status 0-2
* ANC ≥ 1,500/mm³
* Platelet count ≥ 100,000/mm³
* Bilirubin ≤ 2.0 mg/dL
* Alkaline phosphatase ≤ 3 times upper limit of normal (ULN)
* AST ≤ 3 times ULN
* Creatinine ≤ 2 times ULN
* LVEF ≥ 45%
* Corrected pulmonary diffusion capacity ≥ 50%
* No uncontrolled infection
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No other active malignancy (with the exception of nonmelanoma skin cancer) that requires myelosuppressive chemotherapy or radiation therapy
* No HIV positivity

PRIOR CONCURRENT THERAPY:

* More than 3 weeks since prior myelosuppressive chemotherapy, except cyclophosphamide pulsing for stem cell collection)
* No other concurrent immunotherapy, radiotherapy, chemotherapy or antimyeloma therapy
* Concurrent chronic corticosteroids at doses of prednisone ≤ 20 mg per day (or equivalent) allowed
* Concurrent adjuvant hormonal therapy (e.g., tamoxifen citrate or leuprolide acetate) allowed