Thalidomide-Dexamethasone vs Interferon-α-Dexamethasone as Maintenance Treatment after ThaDD Induction for Multiple Myeloma (MM): Final Analysis of a Prospective, Randomized Study.

Maintenance therapy with Thalidomide in MM offer controversial results. De novo or relapsing MM patients presenting at least a minor response after ThaDD were randomized to receive Interferon 3 MU x 3/week or thalidomide 100 mg /d. Both groups were given also Dexamethasone 20 mg/d x 4 days every month. Actually, we have randomized 50 patients in both treatment arms. The two groups were matched for main prognostic factors and response. During maintenance, both the ID and TD regimens improved response obtained by induction in only 10% and 11% of patients, respectively (p=0.832). After a median 2-years maintenance follow-up for both arms, 30 ID patients (60%) relapsed vs 17 (33%) TD ones (p=0.009). Time-to-progression (TTP) was significantly higher in the TD group vs the ID one (p= 0.024). So that TTP amounted to 23% in the ID group vs the 44% in the TD one. In addition, 3-years overall survival (OS) was significantly better in the TD arm with a value of 67% vs 46% of ID (p = 0.030). Both treatment arms were overall fairly well tolerated: fever, anorexia, weight loss, fatigue, liver and heart function abnormalities and hematologic toxicities were significantly more frequent in the ID cohort whereas neurotoxicity was somewhat more frequent in the TD one. This turned into a rate of therapy dropouts rate significantly higher in the ID group than in the TD one (26% vs 8%; p=0.017). Anyway, estimated risk for treatment interruption due to side effects in a 3-years period with thalidomide was only 21% vs 44% for interferon (p =0.014). We concluded that, in MM patients responding to standard induction therapy, low-dose Thalidomide maintenance therapy is feasible even in the long run and offers a significantly longer control over residual disease when compared to standard maintenance regimen.