A systematic review of phase II trials of thalidomide/dexamethasone combination therapy in patients with relapsed or refractory multiple myeloma.
Topic: Immunotherapy

Thalidomide monotherapy in relapsed/refractory multiple myeloma (MM) has a response rate of 30%. The combination of thalidomide with dexamethasone (Thal/Dex) is expected to improve responses, but it is unknown if the combination increases the rate of adverse events. Here, we conducted a systematic review of studies evaluating Thal/Dex in relapsed/refractory MM. Twelve studies were included, comprising 451 patients. The response rate (CR and PR) was 46% (95% CI 42-51%). Therapy-related toxicity was comparable to thalidomide monotherapy and included somnolence (26%, 95% CI 22-31%), constipation (37%, 95% CI 32-42%) and peripheral neuropathy (27%, 95% CI 23-32%). Only venous thromboembolism appeared to occur more often with Thal/Dex (5%, 95% CI 3-8%). Thus, using Thal/Dex results in an improved response rate in relapsed/refractory MM, with a toxicity rate comparable to thalidomide monotherapy.

PICO
Population: Patients with relapsed or refractory multiple myeloma
Intervention: Thalidomide with dexamethasone combination therapy
Comparison: Thalidomide monotherapy
Outcomes: Improved response rate and comparable toxicity rate

Included studies:
title: Thalidomide and dexamethasone combination for refractory multiple myeloma.
abstract: Thalidomide is effective in approximately 30% of patients with refractory multiple myeloma. Dexamethasone is active in 25% of patients with disease resistant to alkylating agents. We investigated the combination of thalidomide with dexamethasone as salvage treatment for heavily pretreated patients with multiple myeloma, in order to assess its efficacy and toxicity.
title: Low-dose thalidomide plus low-dose dexamethasone therapy in patients with refractory multiple myeloma.
abstract: We report the results of a non-randomized phase II study of low-dose thalidomide plus low-dose dexamethasone therapy in 66 patients with refractory multiple myeloma. The overall response rate (near complete, partial and minimal response) was 63.6%, and progression-free and overall survival periods were 6.2 and 25.4 months. In adverse events, the incidence of peripheral neuropathy and deep vein thrombosis was lower than the data reported in USA and Europe. On the other hand, leukopenia was observed in 41% of patients, including 11% of those with Grade 3. Leukopenia was closely related to pretreatment pancytopenia, especially thrombocytopenia. The incidence of adverse events related to dexamethasone was low. In conclusion, low-dose thalidomide plus low-dose dexamethasone therapy was as effective as high-dose thalidomide plus high-dose dexamethasone therapy in patients with refractory multiple myeloma. Leukopenia is one of the most serious adverse events in Japanese patients, especially in patients with pretreatment pancytopenia.
title: Efficacy of low-dose thalidomide and dexamethasone as first salvage regimen in multiple myeloma.
abstract: The efficacy of low-dose thalidomide (THAL) plus dexamethasone (DEX) has been evaluated in myeloma. The clinical outcome of patients treated with THAL-DEX was compared with that of a control group treated with conventional chemotherapy (CC).
title: The combination of intermediate doses of thalidomide with dexamethasone is an effective treatment for patients with refractory/relapsed multiple myeloma and normalizes abnormal bone remodeling, through the reduction of sRANKL/osteoprotegerin ratio.
abstract: The aim of this study was the evaluation of the effect of intermediate doses of thalidomide with dexamethasone (Thal/Dex) on disease course and bone disease in patients with refractory/relapsed myeloma who were under zoledronic acid therapy. We studied 35 patients, who received thalidomide at a dose of 200 mg/daily. We measured, pre-, 3 and 6 months post-treatment soluble receptor activator of nuclear factor-kappaB ligand (sRANKL), osteoprotegerin (OPG), osteopontin (OPN), markers of bone resorption and formation. Before treatment, patients had increased levels of sRANKL/OPG ratio, bone resorption markers and OPN, while they had suppressed bone formation. The pretreatment sRANKL/OPG ratio correlated with the extent of bone disease. Thal/Dex administration resulted in a significant reduction of sRANKL/OPG ratio, and bone resorption. Bone formation, OPG and OPN did not show any alteration. Changes of sRANKL/OPG ratio correlated with changes of bone resorption markers. Thal/Dex was given for a median time of 10 months and the median follow-up period was 22 months. The response rate was 65.7%. The median survival was 19.5 months. beta2-microglobulin, type of response and International Staging System predicted for survival. These results suggest that the combination of intermediate dose of Thal/Dex is effective in patients with refractory/relapsed myeloma and improves abnormal bone remodeling through the reduction of sRANKL/OPG ratio.
title: Thalidomide in combination with dexamethasone for pretreated patients with multiple myeloma: serum level of soluble interleukin-2 receptor as a predictive factor for response rate and for survival.
abstract: The aim of this study was to assess the side effects and the efficacy of thalidomide alone or in combination with dexamethasone in relapsed multiple myeloma (MM) and to evaluate possible predictive factors for response rate and survival. Twenty-nine pretreated patients were enrolled, including 13 patients with a relapse after high-dose chemotherapy. The median number of relapses was 3 (range: 1-7). Twenty-two patients received thalidomide in combination with dexamethasone and seven patients thalidomide alone. The dosage of thalidomide was 400 mg/day and the dosage of dexamethasone 20 mg/m2 daily for 4 consecutive days every 3 weeks. Cycles of dexamethasone were given until maximal decline of myeloma protein was achieved, whereas therapy with thalidomide was maintained until disease progression. Responses occurred in 62% of patients, including 5 (17%) complete remissions and 13 (45%) partial remissions. The median event-free survival (EFS) was 7.2 months and the median overall survival (OS) 26.1 months. In multivariate analysis, pretreatment serum levels of soluble interleukin-2 receptor (sIL-2R) were a significant prognostic factor for EFS, and those of beta2-microglobulin (beta2M) and sIL-2R for OS. Serum levels of sIL-2R significantly increased after 3 weeks of treatment in 89% of patients, possibly representing lymphocyte activation induced by thalidomide. Two patients died of septic complications within 3 months after starting treatment with thalidomide and dexamethasone and one patient of herpes encephalitis after 26 months of treatment with thalidomide alone. Also, one case of pneumonia and one case of deep venous thrombosis of the lower limb occurred. Other side effects were somnolence, peripheral neuropathy, and bradycardia occurring in 35, 55, 38 and 55% of patients, respectively. The combination of thalidomide and dexamethasone is an effective therapy in heavily pretreated myeloma patients with a high response rate and acceptable toxicities. A powerful predictive factor both for EFS and OS was the pretreatment serum level of sIL-2R.
title: Dose-dependent effect of thalidomide on overall survival in relapsed multiple myeloma.
abstract: Although thalidomide (Thal) was introduced successfully in the treatment of multiple myeloma (MM), the optimal Thal dosage and schedule are still controversial. The aim of this study was to analyze whether the effect of Thal in MM is dose dependent and whether the outcome might be improved when the Thal dosage is adjusted to parameters reflecting body size.