AE-941 in Treating Patients With Relapsed or Refractory Multiple Myeloma

DISEASE CHARACTERISTICS: * Diagnosis of multiple myeloma (MM) according to the Durie and Salmon criteria * Refractory to or in early relapse after standard chemotherapy with or without stem cell transplantation * Measurable disease * Quantifiable IgM, IgG, or IgA paraprotein in serum AND/OR * Bence-Jones protein in urine * No plasma cell leukemia (more than 20% plasma cells in peripheral blood and an absolute plasma cell count of at least 2,000/mm3) * No nonsecretory MM * No spinal cord compression PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-2 Life expectancy: * More than 6 months Hematopoietic: * No clinical symptoms of hyperviscosity Hepatic: * Not specified Renal: * Creatinine no greater than 2 times upper limit of normal * Calcium no greater than 11 mg/dL Other: * No other prior malignancy within the past 5 years except basal cell carcinoma of the skin or carcinoma in situ of the cervix * No severe allergy to fish or seafood * No medical condition that would interfere with intake and/or absorption of study medication (e.g., gastrectomy or major intestinal resection) * No significant medical or psychiatric condition that would preclude study participation * Not pregnant * Negative pregnancy test * Fertile patients must use adequate contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * See Disease Characteristics * No prior history of treatment with thalidomide for more than 14 days duration * At least 4 weeks since prior biological therapy for MM * Concurrent epoetin alfa allowed Chemotherapy: * See Disease Characteristics * At least 4 weeks since prior chemotherapy for MM Endocrine therapy: * At least 4 weeks since prior steroid therapy for MM * No prednisone maintenance therapy Radiotherapy: * At least 4 weeks since prior radiotherapy * No concurrent palliative or curative radiotherapy Surgery: * Not specified Other: * At least 28 days since other prior shark cartilage products * At least 28 days since other prior experimental therapeutic agents * Concurrent monthly bisphosphonate (pamidronates) infusions allowed * No other concurrent anticancer treatment * No other concurrent shark cartilage products * No other concurrent therapies for MM