Autologous Hematopoietic Cell Transplantation in Patients With Multiple Myeloma: Effect of Age

Abstract

Background: In the novel and pre-novel agent era, high-dose therapy, followed by autologous hematopoietic cell transplantation (AHCT), has been shown to prolong survival in patients with multiple myeloma (MM) in randomized trials. However, these trials only included patients aged ≤ 65 years. Given that the median age at diagnosis is 66 years, it is important to know the outcomes of AHCT in older patients. Similarly, definite outcomes of AHCT in very young patients (aged < 50 years) are also lacking because they represent a very small proportion of patients in clinical trials.

Materials and methods: We analyzed a consecutive cohort of patients with MM receiving AHCT from 2000 to 2015 in 2 different age groups, older (> 70 years) and younger (≤ 50 years), and compared the outcomes. The primary objectives were to assess overall survival, progression-free survival (PFS), and nonrelapse mortality in these 2 groups.

Results: Of the 191 patients, 86 were young (age ≤ 50 years) and 105 were old (age > 70 years). The younger patients had better performance status and a lower comorbidity index, and most of the older patients had received a melphalan dose of 140 to 180 mg/m². The median follow-up period for the young group was 33 months (range, 2-164 months) compared with 22.5 months (range, 3-133 months) in the old group (P = .02). The PFS rate at 1 year was 60% (95% confidence interval [CI], 46%-72%) for the young group and 58% (95% CI, 45%-69%) for the old group. The overall survival rate at 1 year was 92% (95% CI, 84%-96%) for the young group and 85% (95% CI, 76%-91%) for the old group. On multivariate analysis, age did not have any effect on survival (P = .82); however, the patients with high-risk cytogenetics (hazard ratio [HR], 2.2; 95% CI, 1.06-4.6; P = .04) had worse overall mortality. High-risk cytogenetics (HR, 1.2; 95% CI, 1.1-3.5; P = .004) and no disease response or progressive disease at transplantation (HR, 5.0; 95% CI, 1.8-13.5; P = .02) were significantly associated with worse PFS.

Conclusion: Age should not be a limiting factor in considering the modality of AHCT. However, younger patients might also benefit from additional novel treatment approaches in the setting of clinical trials, given their similar outcomes with the older patients in our study.

Keywords: AHCT; MM; Old patients; Outcomes; Young patients.