Patients with asymptomatic myeloma (smoldering, indolent, and asymptomatic Durie-Salmon Stage I disease) are usually observed without treatment until evidence of disease progression. Because many of these patients eventually progress, studies are being conducted to determine if treatment of asymptomatic disease may delay progression to symptomatic disease.

Results of a study that included 10 patients with indolent myeloma and 19 patients with smoldering myeloma suggested that thalidomide (200-800 mg/day) has significant activity in early stage myeloma. (Rajkumar et al. Leukemia. 2003;17(4):775-779.) Ten patients (34%) had a reduction of M protein of at least 50% and 9 additional patients had a reduction between 25% and 50%, leading to an overall response rate of 66%.

Weber et al also investigated the use of thalidomide (200-600 mg/day) in 28 previously untreated asymptomatic patients who were considered at high risk for disease progression. A total of 36% of patients achieved disease remission (≥75% reduction in M protein) with the agent. (Weber et al. J Clin Oncol. 2003;21(1):16-19.)

Trial summaries, including common side effects and serious adverse events, are noted in the table below. The doses of thalidomide used in these two trials may be considered high by current standards considering the asymptomatic status of the patients evaluated.

It is important to recognize that these patients may remain asymptomatic for long periods of time. Thus, the risks of chronic administration of a drug with significant cumulative toxicity may outweigh the unproven benefits in these types of myeloma patients.