Results of a Canadian retrospective analysis indicate that multiple myeloma patients who develop one or more new monoclonal proteins (M-spikes) after stem cell transplantation may have improved progression-free and overall survival compared to those without a new M-spike.

Myeloma cells overproduce a single type of antibody, known as a monoclonal or M-protein. Different types of myeloma are classified according to the type of M-protein the patient’s myeloma cells produce.

When a patient’s original M-spike disappears and an M-spike of a different monoclonal protein appears, this is known as monoclonal banding.  When the original M-spike disappears and several new M-spikes appear simultaneously, this is known as oligoclonal banding.

"Oligoclonal and monoclonal banding are associated with better overall survival and progression-free survival ... and are also associated with a better quality of response, with most patients achieving VGPR [a very good partial response] after an autologous stem cell transplant," said Dr. Victor Hugo Jimenez-Zepeda from the Princess Margaret Hospital in Toronto, Canada, who presented the findings at the American Society of Hematology (ASH) annual meeting in Atlanta last month.

He noted that the cause of new M-spikes after transplantation is still under investigation and recommended that the impact of new M-spikes on clinical outcomes in multiple myeloma should be further evaluated.

Dr. Jimenez-Zepeda explained that while more than one M-spike may be present at diagnosis and a switch from one M-protein type to another may occur at disease relapse, the type of M-protein normally stays constant throughout the disease.

He added that if a change in M-protein occurs, the change was thought to be transient. However, there has been increasing evidence that the change can last for years.

He also mentioned that a change in M-protein type has frequently been observed with the use of Revlimid ^[1] (lenalidomide) and has been associated with a high degree of response.

In the current study, Dr. Jimenez-Zepeda and his colleagues examined the presence of new M-spikes in patients who underwent stem cell transplantation.

The study included 788 multiple myeloma patients who received a stem cell transplant at Princess Margaret Hospital between January 2000 and December 2007. The median patient age was 58 years.

Overall, 12 percent of patients developed new M-spikes within three months post-transplant. Of these patients, 67 percent developed a single new M-spike, and 33 percent developed several new M-spikes.

New M-spikes of both types emerged after stem cell transplantation in 14 percent of patients who were treated with a combination of vincristine ^[2] (Oncovin), doxorubicin ^[3] (Adriamycin), and dexamethasone ^[4] (Decadron), 7 percent of patients who received Velcade ^[5] (bortezomib), and 9 percent of patients who received a thalidomide ^[6] (Thalomid) regimen. None of the patients included in the analysis had received treatment with Revlimid.

Patients who developed new protein bands within three months after transplantation achieved a higher rate of a very good partial response or better (38 percent), compared to patients who did not develop new bands (28 percent). At 100 days post-transplant, this rate increased to 79 percent in patients with new protein bands, compared to 58 percent for patients without new bands.

In addition, the median progression-free and overall survival times for patients who developed new protein bands (29 months and 116 months, respectively) were significantly longer than those of patients who did not develop any new bands (23 months and 75 months, respectively).

This link between new protein bands and improved survival is statistically significant, the researchers found, even after taking into account patient characteristics at the time of diagnosis, such as each patient's albumin, creatinine, and LDH (lactate dehydrogenase) levels.

For more information, please see abstract 595 ^[7] on the ASH meeting website.