A recent study conducted in China demonstrated that the addition of Velcade to initial thalidomide-dexamethasone treatment confers a low risk of blood clot complications to newly diagnosed multiple myeloma patients.

The researchers suggested that medication for the prevention of blood clots is not needed in newly diagnosed multiple myeloma patients receiving the combination treatment. However this recommendation was limited to Chinese patients only because the study was conducted in a population of Chinese patients.  

The findings cannot be conclusively applied to other ethnicities because the rate of complications resulting from blood clots varies greatly among different ethnicities.

African American patients are at the greatest risk for blood clot-related events, followed by Caucasians and Hispanics. 

Asians and Pacific Islanders, however, have a significantly lower risk of blood clot-related events. In one study, Asian and Pacific Islander cancer patients were 60 to 80 percent less likely to be diagnosed with a blood clot-related event than their Caucasian counterparts (for more information about ethnicity and blood clot complications, please refer to the abstract in Thrombosis Research).

The reason for these differences between ethnicities is still not entirely understood, but is likely a combination of environmental and genetic factors.

Dr. Hongfeng Guo, lead investigator of the study, explained that the increased risk of blood clot complications in Caucasian patients may be at least partially explained by specific genetic mutations in clotting factors. These mutations are very rare in the Chinese population, and, therefore, decrease the risk of blood clot formation.

The study findings do, however, confirm earlier studies conducted in Caucasian populations that suggest Velcade (bortezomib) provides protection against blood clots in multiple myeloma patients (for more information about these earlier studies, please refer to the British Journal of Haematology).

In addition, Dr. Guo further clarified in email correspondence with the Myeloma Beacon that the researchers’ findings may also be applied to other Asian populations and Asian Americans.

Patients with multiple myeloma have an increased risk of developing complications due to the formation of blood clots. Furthermore, the use of some multiple myeloma drugs, such as thalidomide (Thalomid) and Revlimid (lenalidomide), significantly increases the risk of blood clot complications.

The combination of thalidomide and dexamethasone (Decadron) is a common initial, or induction, therapy for myeloma patients. However, this treatment is known to greatly increase a patient’s risk for blood clot-related events.

Previous studies have shown that the rate of blood clot complications was low in myeloma patients who received Velcade in combination with dexamethasone. Although Velcade appears to lower the risk of blood clot complications, the mechanism by which Velcade accomplishes this is not fully understood.

In their study, the researchers sought to determine the effect of the addition of Velcade to thalidomide-dexamethasone induction therapy on the development of complications related to blood clots. 

A total of 32 Chinese patients who received Velcade-thalidomide-dexamethasone (VTD) therapy were included in the study.  Velcade was administered at a dose of 1.3 mg/m² on days 1, 4, 8, and 11 of a 21-day cycle. Dexamethasone, at a dose of 20mg/day, was given on days 1 through 4 and 8 through 11. Thalidomide, at a dose of 100-1200mg/day, was administered daily. 

Anticoagulants, given to prevent the formation of blood clots, were not administered to patients in this study. 

Ninety-one percent of patients responded to the treatment. Nineteen percent of patients achieved a complete response, 13 percent achieved a very good partial response, and 59 percent achieved a partial response.

Complications resulting from blood clots were very low. Only one patient (3 percent) enrolled in the study experienced these complications.

Researchers added that further research is needed to fully understand how Velcade protects against blood clot-related events in multiple myeloma patients.

For more information, please see the study in Leukemia Research (abstract).