High-dose melphalan (MEL) based autotransplants (AT) for multiple myeloma (MM): The Arkansas experience since 1989 in more than 2,800 patients
8043 Background: The dose-response effect for MEL has been safely exploited through the use of AT. Long-term follow-up studies from large centers are critical to understand who benefits most and who should be considered for alternative treatment approaches. Methods: 2,836 patients receiving at least one MEL AT were considered. Kaplan-Meier analysis was used to estimate median event-free survival (EFS) and overall survival (OS). Cox regression was used to evaluate independent prognostic factors of EFS and OS from AT. Results: Of the 2,836 patients, 979 were enrolled into front-line Total Therapy protocols 1/2/3 (TT); 1,064 were entered on protocols for previously treated patients (non-TT); and 793 were treated off protocol (non-P). Overall median EFS and OS from 1st AT are 31mo and 53 mo; 10-yr EFS and OS were 19% and 24%; 15% survived >15 yr. The 5 strongest favorable OS features included TT (HR 0.46, p<0.001), absence of cytogenetic abnormalities (no CA) (HR 0.48, p<0.001), B2M <3 mg/L (HR 0.46, p<0.001), albumin >=3g/dL (HR 0.45, p<0.001) and platelet count >=100.000/microL (HR 0.41, p<.001), so that 10-yr OS rates were 58% with 5, 24% with 4, 16% with 3, 4% with 2 and 0% with =<1 favorable parameter (p<0.0001). The corresponding median durations of EFS were 80 mo, 37 mo, 27 mo, 18 mo and 7 mo (p<0.0001). Conclusion: This large single institution experience demonstrates that > 10 yr OS can be accomplished in over one-half of the 16% of all patients presenting without CA, with low levels of B2M and albumin, high platelet count and receiving TT. The worst constellation affected 3% of all patients presenting with at most 1 good-risk feature whose 5-yr survival was only 7%. These data should serve as guidepost for MM investigators and patients alike, against which newer treatments should be measured. No significant financial relationships to disclose.