Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of myelofibrosis with myeloid metaplasia, including any of the following
subtypes:

- Agnogenic myeloid metaplasia

- Post-polycythemic myeloid metaplasia

- Post-thrombocythemic myeloid metaplasia

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- ECOG 0-2

Life expectancy

- Not specified

Hematopoietic

- Absolute neutrophil count ≥ 1,000/mm^3

- Platelet count ≥ 100,000/mm^3

- Hemoglobin ≤ 10 g/dL OR

- Transfusion dependent

Hepatic

- Total or direct bilirubin ≤ 2.0 mg/dL

- AST ≤ 3 times upper limit of normal (unless due to hepatic extramedullary
hematopoiesis)

- No hepatitis A, B, or C infection

Renal

- Creatinine ≤ 2.0 mg/dL

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No known HIV positivity

- No condition or laboratory abnormality that would preclude study participation

- No other active malignancy

- No known hypersensitivity to thalidomide or lenalidomide

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No prior lenalidomide

- At least 28 days since prior interferon alfa, thalidomide, or growth factors

- No concurrent growth factors

Chemotherapy

- At least 28 days since prior chemotherapy

- At least 28 days since prior hydroxyurea

Endocrine therapy

- At least 28 days since prior systemic corticosteroids

Radiotherapy

- Not specified

Surgery

- Not specified

Other

- Recovered from prior therapy

- At least 28 days since prior anagrelide or other myelosuppressive agents

- At least 28 days since prior experimental therapy