Results of a recent Canadian study show that the use of novel agents, particularly Velcade and Revlimid, as salvage therapy after stem cell transplantation improves overall survival and post-relapse survival of multiple myeloma patients, including high-risk patients who relapsed early following transplantation.

Although multiple myeloma remains an incurable disease, the introduction of novel agents, such as thalidomide ^[1] (Thalomid), Velcade ^[2] (bortezomib), and Revlimid ^[3] (lenalidomide) has lead to significant improvements in disease outcomes.

In their analysis, the Canadian researchers sought to determine the effect of these novel agents on the outcomes of multiple myeloma patients who had relapsed after stem cell transplantation.

They also sought to determine if novel agent therapy has improved the outcomes for a subset of patients considered high-risk due to early relapse (less than 12 months) following transplantation.

The Canadian researchers analyzed data collected from 460 multiple myeloma patients who received an autologous stem cell transplant in British Columbia, Canada, between June 1988 and June 2008.

The novel therapeutic agents administered in the event of a relapse following transplantation (post-relapse, or salvage, therapy) were developed during the 20 year study period, which allowed the researchers to compare the relative efficacy of each drug.

Prior to 1999, post-relapse therapy in British Columbia was comprised of various chemotherapy regimens. Thalidomide was first available for post-relapse therapy in 1999, followed by Velcade in 2004, and Revlimid in 2005.

Of the 460 patients included in the study, 306 experienced relapse following stem cell transplantation. Among these relapsed patients, the overall survival was 59.6 months, and the median post-relapse survival was 31 months.

The analysis showed that there was little difference in the post-relapse survival between patients who received conventional chemotherapy and those who received thalidomide as post-relapse therapy.

The researchers therefore divided the relapsed patients into two groups: (1) those who relapsed prior to 2004 and received post-relapse chemotherapy or thalidomide, and (2) those who relapsed in 2004 or later and received the novel agents Velcade or Revlimid as part of post-relapse therapy.

Overall survival significantly improved for patients who relapsed in 2004 or later (71.8 months), compared to patients relapsing prior to 2004 (32 months).

Likewise, the post-relapse survival also improved in the more recently relapsed group, with a median of 42.8 months compared to 15.2 months in those relapsing prior to 2004.

Progression-free survival after transplantation was similar for the two groups (19.9 months versus 14.6 months), which according to the study authors is an indication that any potential changes that were made to transplantation procedures over time did not have an impact on outcome.

When researchers analyzed the relationship between early relapse following transplantation, overall survival, and post-relapse survival, they found that patients who relapsed early had lower overall survival times (26.8 months) compared to those with a later relapse (75 months).

Patients who relapsed early also had lower post-relapse survival times (16.3 months) than patients who relapsed later (37.2 months).

Early relapse patients who relapsed in 2004 or later did, however, experience an improvement in post-relapse survival time (33.4 months) compared to those who relapsed prior to 2004 (9.1 months).

For more information, see the research article in Leukemia & Lymphoma ^[4] (abstract).