Multiple myeloma patients on various thalidomide ^[1] (Thalomid) combination regimens may develop infections despite preventative drug measures, according to a data analysis performed by Italian researchers. The analysis also identified which factors increase a patient’s likelihood of experiencing severe infection. Researchers presented the results on December 6 at the 51st annual meeting of the American Society of Hematology (ASH) in New Orleans.

In the process of treating multiple myeloma, patients often experience a weakening in their immune system which makes them more susceptible to infection. Serious infections can lower a patient’s quality of life, require doctors to reduce treatment to a less toxic but less effective level, and even cause death.

Doctors can treat infection as it occurs or anticipate and prevent it. Prophylaxis refers to any medication used to prevent illness from developing as opposed to fighting it once it has arisen.

In their analysis, researchers examined how effective antibacterial prophylaxes were in preventing infection in patients on various thalidomide combination regimens.

The researchers analyzed the data of 224 patients, 168 of whom received medication to prevent infections. Patients received any one of the following five thalidomide combination regimens: thalidomide, dexamethasone ^[2] (Decadron), and Doxil ^[3] (pegylated liposomal doxorubicin); thalidomide, dexamethasone, and Doxil plus Velcade ^[4] (bortezomib); thalidomide and dexamethasone; thalidomide and dexamethasone plus Velcade; or a combination of Velcade, melphalan ^[5], prednisone ^[6], and thalidomide. Participants ranged in age from 31 to 90, with a median age of 70.

Of the 224 patients, 86 (38.5 percent) developed infection, and 39 (17.5 percent) experienced severe infections. Severe infections included pneumonia (59 percent), unidentifiable fevers (23 percent), bacteria in the blood (15 percent), and swelling of eye tissue (3 percent). One patient with bacteria in the blood died of septic shock.

Out of the 168 patients given prophylaxis, 15 percent developed infection. In contrast, 25 percent of the 56 patients not given preventative medication experienced infection.

Upon analysis of the patient data, researchers pinpointed factors that were associated with an increased risk of severe infection. These factors included having an increased monoclonal protein (M protein) count (> 2 g/mL of blood) and a decreased platelet count (< 130 cells/mL). Patients with neither of these factors were at a 4 percent chance of developing severe infection. Patients with one factor faced a 17 percent risk, and patients with both factors had a 32 percent chance of acquiring severe infection. Factors that did not affect risk of infection included type and stage of multiple myeloma; haemoglobin, albumin, and other protein levels; and prior experience with stem cell transplantation.

Patients who experienced severe infection were more likely to suffer from deep vein thrombosis, or blood clotting in the deep veins of the body.

Researchers concluded that antibacterial prophylaxis did not completely prevent the risk of developing infection, but antibiotic treatment could be used to fight infection once it occurred. They also recommended that patients with the two identified risk factors be treated with antimicrobial prophylaxes, which fight not only bacteria, but also fungi and viruses.

For more information, please see abstract 2828 ^[7] at the ASH meeting Web site.