A Randomized, Double-Blind, Placebo-Controlled Trial of Thalidomide Plus Dexamethasone Versus Dexamethasone Alone as Primary Therapy for Newly Diagnosed Multiple Myeloma.

Purpose: Updated results, including response rate data, from a randomized, double-blind, placebo-controlled study comparing thalidomide plus dexamethasone versus dexamethasone alone as primary therapy for newly diagnosed multiple myeloma (MM).

Methods: Patients (pts) with previously untreated, symptomatic MM were eligible. Pts were randomized to Thal/Dex (Arm A) or placebo plus Dex (Arm B). Pts in Arm A received Thal 50 mg PO daily, escalated to 100 mg on day 15, and to 200 mg from day 1 of cycle 2; Dex 40 mg PO was given on days 1–4, 9–12, and 17–20. Pts in Arm B received placebo instead of Thal, and Dex as in Arm A. Each cycles was 28 days long. Treatment was continued until progression or undue toxicity. The primary endpoint was time to progression (TTP) defined using EBMT criteria. All analyses were conducted on an intent to treat basis. An independent data monitoring committee recommended release of results.

Results: 470 pts were enrolled: 235 were randomized to Thal/Dex and 235 to placebo/Dex. Median follow up is 18 months. Median age was 65 yrs. The response rate (CR+PR) was significantly higher with Thal/Dex compared to placebo/Dex, 59% vs 42%, respectively, P<0.001. Eighty-two percent of patients have gone off-study. TTP was significantly superior with Thal/Dex vs placebo/Dex, median TTP not reached with Thal/Dex versus 8.1 months (95% CI: 6.5–12.8 months) with placebo/Dex, P<0.001. Major grade 3–4 events are summarized in the Table below. Deep vein thrombosis (DVT) was higher with Thal/Dex vs placebo/Dex, 15.4% vs 4.3%, respectively.

Conclusions: Thal/Dex yields superior response rates and TTP compared to Dex alone when used as first-line therapy for multiple myeloma.