A combination of cyclophosphamide, low-dose thalidomide, and dexamethasone is effective and well tolerated in multiple myeloma patients, according to a recent Polish study. Response rates were favorable for both newly diagnosed and relapsed or treatment-resistant multiple myeloma patients.

 “Low-dose thalidomide was well tolerated, and serious side effects described with high or even intermediate doses were diminished,” said Dr. Anna Dmoszynska, the lead author of the study, in an email to the Beacon.

In recent years, thalidomide ^[1] (Thalomid) has proven to be an effective therapy for multiple myeloma when given alone or in combination with other drugs. One such combination consists of cyclophosphamide ^[2], thalidomide, and dexamethasone ^[3] (Decadron).

The results of a study published in March showed that this therapy, commonly referred to as CTD, is effective for newly diagnosed multiple myeloma patients (see related Beacon ^[4] news).

However, treatment with thalidomide is associated with an increased risk of blood clot formation and nerve damage.

The goal of the Polish study was to determine the safety and efficacy of CTD with low-dose thalidomide as a therapy for newly diagnosed multiple myeloma patients prior to stem cell transplantation as well as salvage therapy in relapsed and treatment-resistant (refractory) myeloma patients.

Low-dose thalidomide (100 mg) was used in an attempt to decrease side effects observed at higher doses (300 mg to 800 mg).

A total of 132 patients were included in the study, 64 of whom were newly diagnosed and 68 of whom had received prior treatment.

Patients received cyclophosphamide (625 mg/m² orally on day 1), thalidomide (100 mg orally on days 1 to 28), and dexamethasone (20 mg orally on days 1 to 4 and 8 to 11) in 28-day treatment cycles. The median number of cycles administered was 6, ranging from 3 to 9 cycles.

Of the newly diagnosed myeloma patients receiving CTD, 74 percent achieved a partial response or better.  Forty nine percent of treatment resistant patients and 65 percent of relapsed myeloma patients also achieved a partial response or better during treatment.  

Complete remission was achieved in 9.4 percent of newly diagnosed patients and 3.9 and 5.9 percent of resistant and relapsed patients, respectively.

The median time to disease progression was significantly longer in newly diagnosed patients (21 months) compared to resistant and relapsed patients (15 months and 10 months, respectively).

At 20 months after start of treatment, 73 percent of both newly diagnosed and resistant myeloma patients were alive, compared to 51 percent of relapsed patients. 

CTD with low-dose thalidomide was well tolerated in most patients.  The most common side effect was nerve damage to the extremities, which was observed in 26 percent of patients. Nerve damage was severe enough to stop treatment in 3 percent of patients.

The researchers pointed out that more comparative research is necessary in order to optimize the dosages and administration of the CTD regimen.

However, Dr. Dmoszynska believes the therapy may become important in situations where cost is an issue. “It is not expensive in comparison to other protocols, but it is very effective. The three drugs are also administered orally, so it is ideal for outpatient treatment.”

For more information, please see the study in Leukemia Research ^[5] (abstract).