Influence of Race on Outcomes in Multiple Myeloma Patients with Renal Dysfunction Undergoing High Dose Therapy Followed By Autologous Stem Cell Transplant
Authors: Nandagopal Lakshminarayanan , Ye J. Christine , Ventimiglia Marie , Abidi Muneer H. , Ayash Lois , Zonder Jeffrey , Lum Lawrence G , Uberti Joseph P. , Ratanatharathorn Voravit , Bhutani Divaya , Deol Abhinav 
Published: October 2019

Abstract
Approximately 20% of Multiple Myeloma (MM) patients (pts) have renal dysfunction(RD) at the time of diagnosis and some more may develop it during the course of their disease. Autologous stem cell transplant (ASCT) is a treatment modality for this incurable malignancy and there are ongoing studies to determine the optimal timing of ASCT in this disease. There are conflicting data regarding the outcomes among different racial groups with regards to ASCT in MM. In this restrospective review we studied outcomes in pts of different races with RD undergoing ASCT for MM.
Between June 2005 and December 2013, we identified 107 pts with MM with RD (creatinine clearance < 60 ml/min/1.73 m2) who were not on hemodialysis and underwent ASCT at our institution. Of the 107 pts, 76 were caucasian(C) pts and 31 were identified as other (O) races (25 African American, one Hispanic, two Middle-eastern, three Asian). The patient characteristics of both groups are shown in Table 1. There were no statistically significant differences in the characteristics between the 2 groups. Approximately a quarter of the pts received their melphalan dose on the inpatient unit in both groups. During the hospitalization all pts received G-CSF from Day +6 till absolute neutrophil count ≥ 1500/µl and antimicrobial prophylaxis with norfloxacin, acyclovir and fluconazole.
The median follow up was 35.9 months (range, 5.1-106.3). One patient in the C group died 98 days after ASCT and had evidence of disease progression. There were no deaths in the O group during the 100 days after ASCT. Table 2 shows post ASCT disease status and details about post ASCT maintenance therapy. There were no statistically significant differences between the groups in disease status or change in disease status at day 100 post ASCT. Although more patients in the C group received maintenance therapy post ASCT, this difference was not statistically significant. Figures 1 and 2 show the relapse free survival (RFS)and overall survival (OS) of both groups. The median RFS for C and O groups were 32.3 and 20.9 months (p =0.63, log rank), respectively. The median OS of the C and O groups were 73.1 and 47.8 month (p=0.31, log rank), respectively.
Our limited experience suggests that there was no effect of race in the post ASCT outcomes for MM pts with RD. ASCT was safe with acceptable transplant related mortality and good long -term outcomes for MM pts with renal dysfunction.
Table 1: Patient Characteristics (N=107) Patient Characteristics Caucasians (n=76) Others (n=31) Median Age (range) 63 (36-73) 64(28-73) 0.58 Gender Male 42 (55%) 17 (55%) 0.9 Females 35 (45%) 14 (45%) Chemo regimens prior to ASCT 1 51 (67%) 21 (68%) 0.95 ≥ 2 25 (33%) 10 (32%) Agents used prior to ASCT IMid 12 (16%) 4 (13%) 0.85 PI 18 (24%) 9 (29%) Both 46 (60%) 18 (58%) Disease status at time of ASCT PD 7 (10%) 5 (16%) 0.35 SD 9 (12%) 4 (13%) PR 20 (26%) 11 (35%) VGPR 20 (26%) 8 (26%) CR 20 (26%) 3 (10%) Median creatinine clearance (range) 45.5 (15-60) 43 (21-60) 0.35 Subtype* IgG Kappa 29 (34%) 18 (58%) 0.25 IgG Lambda 18 (24%) 6 (19%) Ig A Kappa 9 (12%) 2 (6%) Ig A Lambda 5 (7%) 3 (10%) K Light Chain 6 (8%) 0 L Light Chain 5 (7%) 0 Non- Secretory 3 (4%) 2 (6%) Cytogenetic Risk Standard 65 (85%) 18 (58%) 0.67 High Risk 5 (7%) 2 (6%) Median Melphalan Dose mg/m2 (range) 140 (140-200) {140(58),160(5), 180(4),200(9)}® 140 (100-200) {100(2),140(25), 200(9)} 0.89 Administration of Melphalan Inpatient 18 (24%) 9 (29%) 0.56 Outpatient 58 (76%) 22 (71%) Median CD 34 Cell dose x106/kg (range) 3.3 (2 -10.1) 3.9 (2.3-9.5) 0.34 Median Engraftment Day (range) Neutrophil 12 (11-20) 12(10-27) 0.86 Platelets 18(11-88) 17 (11-42) 0.10 Median Days of Hospitalization (range) 15 (9-65) 16 (12-55) 0.96
* 1 pt each in the caucasian group had IgD Lambda and IgM Kappa paraprotein
® Pts received 160 and 180 mg doses as part of a study
PI: proteosome inhibitors, PD: progressive disease, SD: stable disease, PR: partial response, VGPR: very good partial response, CR: Complete response
Table 2: Disease status at Day 100 post ASCT Caucasian (N=76) Other (N=31) P Value Disease Status CR 26 (34%) 6 (19%) 0.5 VGPR 20 (26%) 12 (38%) PR 17 (22%) 6 (19%) SD 7 (9%) 4 (13%) PD 2 (3%) 2 (7%) Not available 4 (6%) 1 (3%) Change in Disease Status Improved 23 (30%) 13 (42%) 0.66 Unchanged 45 (59%) 15 (48%) Worsened 4 (6%) 2 (7%) Not available 4 (6%) 1 (3%) Maintenance Therapy IMid 40 (53%) 9 (29%) 0.15 PI 2 (3%) 1 (3%) None 29 (38%) 19 (61%) Not Known 5 (7%) 2 (7%)
Figure 1 Figure 1.
Figure 2 Figure 2.

Disclosures
No relevant conflicts of interest to declare.