The impact of venous thrombotic events (VTE) on overall survival in patients with newly diagnosed multiple myeloma was examined in a study presented at the 2008 American Society of Hematology (ASH) meeting.

VTE occurs when a blood clot fully or partially blocks a vein, which carries blood back to the heart.  This can result in deep vein thrombosis (when a deep vein is blocked) or pulmonary embolism (when a clot dislodges and blocks an artery in the lungs).  VTE is a frequent complication of the Revlimid (lenalidomide)-dexamethasone combination treatment currently recommended as an initial therapy in newly diagnosed patients prior to stem cell transplantation.

Researchers studied the incidence of VTE after patients were treated with either Revlimid plus a standard dose of dexamethasone (Rev-dex) or Revlimid plus a lower dose of dexamethasone [Red-(ld)dex].

A total of 445 patients with previously untreated multiple myeloma were enrolled in the trial; 223 received the Rev-dex treatment while 222 received Red-(ld)dex.  Thromboprophylaxis—the administration of anti-clot medication when VTE risk factors are present—was required in the study after the first 264 patients were enrolled.  Average follow-up time was 30 months.

Overall, VTE occurred in 18.5 percent of patients.  Of those receiving the Rev-dex treatment 25.6 percent developed VTE, whereas only 11.4 percent of the Rev-(ld)dex group were similarly affected.

Patients with VTE also developed significant other side effects, including hyperglycemia (high blood sugar), cardiac ischemia (obstruction of blood flow to the heart), non-neuropathic weakness, pneumonia, and fatigue.  According to a statistical analysis the researchers performed, patients with VTE have a higher risk of death. 

The researchers concluded that VTE prevention is therefore critically important.  A lower dose of dex appears partially effective in reducing the incidence of VTE, but further studies exploring optimal thromboprophylaxis are needed. 

For more information, see abstract 1740 from ASH 2008.