Thalidomide and its analogues in the treatment of Multiple Myeloma

Multiple myeloma is a mature B-cell neoplasm characterized by a monoclonal expansion of plasma cells in the bone marrow often accompanied by hemocytopenias, immunodeficiency, osteolytic lesions, hypercalcemia and renal failure. Myeloma accounts for about 10% of all hematological malignancies and 1% of all cancers [1]. In United States alone an estimated 20,520 new cases (11,400 men and 9120 women) will be diagnosed in 2011 and 10,610 people will die of myeloma [2]. Ever since the first reported case of ‘mollities ossium’ described in 1844 [3], the disease has remained incurable, despite a better understanding of its pathogenesis and recent advancements in therapeutics. Prior to the advent of alkylating agents, the median survival for multiple myeloma was 1–1.5 years [4]. Following the introduction of L-phenylalanine mustard or melphalan in 1958 [5] and prednisone in 1962 [6], the combination of these two drugs remained the cornerstone of therapy for more than two decades, even though the complete remission rate remained less than 5% and the median survival with this treatment did not exceed 3 years [7]. Since the late 1990s, a number of new classes of drugs have been incorporated in the treatment of multiple myeloma and additional agents are under investigation (Figure 1). The present paper will review the clinical data for the use of thalidomide and its analogs, collectively referred as immunomodulatory drugs or IMiDs in multiple myeloma.Thalidomide was first introduced as an oral sedative and anti-emetic in 1957, but was quickly abandoned due to its profound teratogenic effects. Almost four decades passed before studies demonstrated thalidomide to have anti-cancer properties, specifically showing significant in vitro anti-myeloma activity. It found its use as a novel anti-myeloma drug for relapsed and refractory disease in 1999 [8], later yielding impressive overall response rates of up to 50% when used in combination with dexamethasone and up to 65% when combined