Changes in survival rate of multiple myeloma after the introduction of bortezomib: a single institutional experience over 20 years.

The data of factors on the changes in survival before and after the introduction of bortezomib in unselected multiple myeloma (MM) patients is scarce in Asian population. We analyzed the clinical features and treatment outcomes of 270 consecutive MM patients admitted to our hospital between January 1995 and August 2014. The patients were divided into two groups, 1995–2005 (n=106) and 2006–2014 (n=164), based on bortezomib availability. There were no differences in baseline characteristics between the groups, except age and percentage of patients receiving autologous stem cell transplantation (auto-SCT). The proportion of patients obtaining ≥very good partial response (VGPR) was higher in the recent cohort, which was translated as better overall survival in both younger and older patients (36.1 vs. 79.8 months, P=0.024, and 40.0 vs. 110.7 months, respectively). Patients receiving bortezomib early after diagnosis showed significantly better survival. However, there was no difference in survival between patients obtaining ≥VGPR in the two groups. On multivariate analysis, age ≥75 and lactate dehydrogenase (LDH) >normal were associated with shorter survival, while early bortezomib use and auto-SCT were associated with longer survival. On Cox regression analysis, International Staging System (ISS) stage III, LDH, and treatment response <VGPR in the previous cohort and ISS stage III, creatinine ≥2.0 mg/dL, and treatment response <VGPR in the recent cohort were associated with poorer survival. Our observations indicated marked improvement of survival in MM patients diagnosed from 2006 to 2014 mainly due to the availability of bortezomib in Japan.