| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2755524 | Clinical Lymphoma Myeloma and Leukemia | 2010 | 7 Pages |
BackgroundAn unexplained survival difference was observed in the Nordic Myeloma Study Group (NMSG) high-dose therapy trial 5/94 in Denmark compared with Sweden and Norway; however, this difference was eliminated in the subsequent NMSG trial 7/98. It was hypothesized that a detailed analysis of potential explanations would reveal important information for future designs of clinical trials for multiple myeloma (MM) patients in Denmark.Patients and MethodsThe analysis is based on 3 consecutive clinical trials coordinated by NMSG from 1990 to 2000: NMSG 4/90 including 583 patients, NMSG 5/94 including 274 patients and NMSG 7/98 including 414 patients with newly diagnosed MM. Event-free and total survival rates were calculated according to the Kaplan-Meier method, and survival comparisons were made by the log-rank test. The Cox proportional hazards regression model was used to estimate the prognostic importance of selected variables.ResultsThe analysis revealed no differences in disease stages, prognostic variables, or inclusion bias at diagnosis between the 3 consecutive NMSG trials. However, the number of initial treatment failures was low, and post-relapse survival was superior in Swedish patients as compared to Danish patients. These differences were explained by a defensive clinical practice in Denmark during 1994-1997 for patients with poor risk refractory or relapsed disease.ConclusionThese initially observed differences were subsequently eliminated most likely as a consequence of international collaboration improving diagnosis, research infrastructure, clinical training, and education as planned within the European Myeloma Network (EMN).
