Inclusion Criteria

DISEASE CHARACTERISTICS:

- New or prior diagnosis of 1 of the following:

- Monoclonal gammopathy of undetermined significance

- Bone marrow plasma cells of less than 10%

- Monoclonal gammopathy of borderline significance

- Bone marrow plasma cells of 10-30%

- Serum IgG or IgA at least 1.5 g/dL

- Bone marrow plasmacytosis no greater than 30%

- No multiple myeloma, amyloidosis, or B-cell neoplasm

- No evidence of bone lesions

- Prostate-specific antigen less than 4 ng/mL

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- ECOG 0-1

Life expectancy:

- Not specified

Hematopoietic:

- See Disease Characteristics

Hepatic:

- Bilirubin no greater than 1.5 times upper limit of normal (ULN) (unless history of
Gilbert's disease)

- AST and ALT no greater than 1.5 times ULN (unless history of Gilbert's disease)

Renal:

- Creatinine no greater than 1.8 mg/dL

Cardiovascular:

- No New York Heart Association class III or IV heart disease

- No prior thromboembolic event within the past 5 years

Other:

- No prostate cancer or clinically significant benign prostatic hypertrophy

- No prior malignancy within the past 5 years except nonmelanoma skin cancer or
carcinoma in situ of the cervix

- No malignancy suspected on mammogram

- No hypersensitivity to DHEA, clarithromycin, or any macrolide antibiotic (e.g.,
erythromycin)

- No insulin-dependent diabetes

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective barrier method of contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- Not specified

Endocrine therapy:

- At least 30 days since prior DHEA or other steroids that may affect M protein

Radiotherapy:

- Not specified

Surgery:

- Not specified

Other:

- At least 30 days since prior clarithromycin

- At least 30 days since any other prior agents that may affect M protein

- No concurrent cisapride, terfenadine, pimozide, astemizole, or loratadine