Introduction

Salvage autologous stem cell transplant (sASCT) may be associated with improved survival in multiple myeloma (MM) and is an option for patients with long time to relapse (TTR) after initial Autologous transplant (ASCT1). Due to potential mobilization failure after maintenance therapy (MT), adequate peripheral blood progenitor cells (PBPC) are frequently collected for later sASCT.

Objectives

Evaluate utilization of stored PBPC in MM. Provide a cost analysis of collecting and storing PBPC for sASCT. Determine utilization of sASCT in those eligible who had a prolonged TTR.

Methods

We included MM patients who received ASCT1 at our institution between 2009 and 2016. Extra day of collection (EDC) was defined as additional collection of ≥2 × 10⁶ cells/kg PBPC for a second transplant. TTR was calculated as months from ASCT1 to relapse. Eligibility for sASCT was defined as TTR ≥18 months without MT or ≥36 months on MT. Patients who underwent tandem transplant (tASCT) (defined as two transplants within 6 months) were excluded from relapse analysis. Patients with inadequate relapse data defined as death or lost to follow up (LTFU) at ≤36 months prior to relapse, or ≤6 months follow up after relapse were excluded. Costs were obtained from the institution charge master. Descriptive statistics were calculated for the final cost benefit analysis.

Results

154 MM patients received ASCT1 from 2009-2016. Median age was 59 years. Median follow up was 151 months. Median TTR was 20 months. 58% were male. Ethnicity was 76% Caucasian and 24% Black. 62% had IgG MM subtype, 23% IgA MM and 15% other. Majority (95%) were European Cooperative Oncology Group (ECOG) 0 or 1. 13% had high risk cytogenetics. 53% received MT.

137(89%) had PBSC stored for sASCT. 3 were used for sASCT and 10 for tASCT. 124 (90.5%) did not use stored cells. 54 (39%) met collection targets for two transplants in single collection while 83 (%) required ≥1 EDC with cumulative 108 EDC. (Figure 1)

Cumulative cost savings for plerixafor use, cell collection, processing, analysis and storage was estimated at $2,252,244. (Figure 2). Total 60 doses of plerixafor were used for EDC. (31 patients with 1EDC, 10 with 2EDC and 3 with 3 EDC).

97 patients were studied for relapses. 54 (77.5%) relapsed. 5 deaths and 8 LTFU occurred within ≤6 months of relapse. 42 patients were further analyzed. 25 of them met criteria for sASCT based on TTR and only 2 received sASCT.1 patient with sASCT did not have MT data and was excluded. (Figure 3)

Conclusion

Only 25% (24/98) patients who underwent ASCT1 were eligible for sASCT. Only 2% (2/98) received sASCT. Collecting and storing PBPC for sASCT is associated with high cost, but overall utilization at our institution is low. Our findings should be compared against practices at other institutions to help develop guidelines for selection of subset of MM where this practice may be of higher value.

中文翻译：

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在多发性骨髓瘤中保存外周血祖细胞用于自体干细胞移植的价值和成本效益

介绍

抢救自体干细胞移植（sASCT）可能与多发性骨髓瘤（MM）的存活率提高有关，对于初次自体移植（ASCT1）后复发时间长（TTR）的患者来说，这是一种选择。由于维持治疗（MT）后潜在的动员失败，经常需要收集足够的外周血祖细胞（PBPC）用于以后的sASCT。

目标

评估MM中存储的PBPC的利用率。提供为sASCT收集和存储PBPC的成本分析。确定在较长TTR的合格患者中使用sASCT。

方法

我们纳入了2009年至2016年间在我们机构接受ASCT1的MM患者。额外的收集日（EDC）定义为第二次移植时≥2×10 ⁶细胞/ kg PBPC的额外收集。TTR计算为从ASCT1到复发的月份。sASCT的资格定义为TTR≥18个月（无MT）或≥36个月（MT）。进行串联分析（tASCT）（定义为6个月内两次移植）的患者被排除在复发分析之外。复发数据不足（定义为死亡前≤36个月或复发后≤6个月的死亡或无法随访）的患者被排除。费用是从机构负责人那里获得的。计算描述性统计数据以进行最终成本收益分析。

结果

从2009年至2016年，有154例MM患者接受了ASCT1治疗。中位年龄为59岁。中位随访时间为151个月。TTR中位数为20个月。58％是男性。种族是76％的白人和24％的黑人。62％的患者患有IgG MM亚型，23％的IgA MM和其他15％的患者。多数（95％）为欧洲合作肿瘤小组（ECOG）0或1。13％的患者具有高风险的细胞遗传学。53％获得MT。

137（89％）人的PBSC被保存用于sASCT。sASCT使用3个，tASCT使用10个。124个（90.5％）未使用存储的单元格。54个（39％）达到了单次收集两次移植的收集目标，而83（％）要求≥1 EDC和累积108 EDC。（图1）

plerixa用于使用，细胞收集，处理，分析和存储的累计成本节省估计为2,252,244美元。（图2）。总共60剂量的plerixafor用于EDC。（31例1EDC，10例2EDC和3例3 EDC）。

研究了97例复发患者。复发54（77.5％）。复发≤6个月内发生5例死亡和8例LTFU。对42例患者进行了进一步分析。其中25个符合基于TTR的sASCT标准，只有2例接受了sASCT。1例sASCT患者没有MT数据，被排除在外。（图3）

结论

接受ASCT1的患者只有25％（24/98）有资格参加sASCT。只有2％（2/98）接受了sASCT。用于sASCT的PBPC的收集和存储成本较高，但是我们机构的总体利用率较低。应该将我们的发现与其他机构的实践进行比较，以帮助制定选择MM子集的准则，而该准则可能具有更高的价值。