Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically proven multiple myeloma Initial diagnosis must
have been confirmed by one of the following prior to initial treatment for multiple
myeloma: Biopsy of an osteolytic lesion or soft tissue tumor composed of plasma cells Bone
marrow aspirate and/or biopsy demonstrating at least 10% plasmacytosis Bone marrow
containing less than 10% plasma cells but with at least 1 bony lesion and the M-protein
criteria outlined below Measurable serum M-component of IgG, IgA, IgD, or IgE at initial
diagnosis OR If only light chain disease (urine M-protein only) present, then the urinary
excretion of light chain (Bence Jones) protein must have been at least 1.0 g/24 hours at
time of initial diagnosis Must have undergone autologous stem cell transplantation within
1 year of beginning initial chemotherapy for multiple myeloma Must be randomized 60-100
days after autologous stem cell infusion No evidence of progressive disease

PATIENT CHARACTERISTICS: Age: 16 and over Performance status: ECOG 0-2 Life expectancy: At
least 6 months Hematopoietic: See Disease Characteristics Granulocyte count at least
1,000/mm3 Platelet count at least 100,000/mm3 Hepatic: AST and/or ALT no greater than 1.5
times upper limit of normal (ULN) Alkaline phosphatase no greater than 1.5 times ULN
Renal: Creatinine no greater than 3 times ULN Cardiovascular: No uncontrolled hypertension
Other: Not pregnant or nursing Negative pregnancy test Fertile female patients must use 2
effective methods of contraception (1 barrier and 1 hormonal) during and for 1 month after
study Fertile male patients must use effective barrier contraception during and for 1
month after study No other medical condition that would preclude long term use of
prednisone or thalidomide No other malignancy within the past 5 years except adequately
treated squamous cell or basal cell skin cancer or carcinoma in situ of the cervix No
diabetes with end stage organ damage No history of gastric ulceration or bleeding No
avascular necrosis of the hips No peripheral neuropathy causing symptomatic dysfunction
Sensory symptoms induced by vincristine allowed No demonstrated hypersensitivity to
thalidomide or its components No other major medical illness that would increase risk or
preclude study No employment that prohibits the use of sedatives (due to known effect of
thalidomide)

PRIOR CONCURRENT THERAPY: Biologic: See Disease Characteristics No prior thalidomide
Chemotherapy: See Disease Characteristics Endocrine: Not specified Radiotherapy: Not
specified Surgery: Not specified Other: No other concurrent anticancer treatment No other
concurrent investigational therapy