Safety, Feasibility and Healthcare Cost Differences between Inpatient and Outpatient Mobilization Chemotherapy for Autologous Hematopoietic Stem Cell Transplantation in Multiple Myeloma: A Single Center Experience
Authors: Thong Edwin , Poon Michelle , Lim Pamela , Kumari Shikha , Yelly . , Lim Hui Li , Lieow Jedidah , Lee Yee Mei , Tan Lip Kun , Koh Liang Piu , Chng Wee Joo , Lee Joanne 
Published: November 2021

Abstract
Introduction
The standard of care for patients with multiple myeloma (MM) involves autologous hematopoietic stem cell transplantation (ASCT). Pre-ASCT mobilization chemotherapy for MM, vinorelbine and high dose cyclophosphamide (VC), has been historically given in the inpatient (IP) setting. Due to rising bed occupancy rates and patients' preferences for treatment in the ambulatory setting, our team has offered eligible patients an option to receive VC outpatient (OP) since 2018. Our study aims to audit the feasibility and safety of this initiative, and review potential healthcare-related cost savings.
Methods
Eligibility criteria for OP chemotherapy were developed by a multidisciplinary team based on patients' age, functional status, medical comorbidities and social factors (Figure 1). The chemotherapy regimen was modified for an OP setting (Figure 2), of which the main alteration involved changing the route of administration of intravenous (IV) mesna to a combination of IV and oral. A retrospective review was conducted for 35 MM patients (18 IP and 17 OP) who received VC for mobilisation at our center from 2018 to 2019. The patient characteristics were similar between the two groups (Table 1). Patient data were analyzed from the day of admission for VC (IP) or day 1 of VC (OP), to the day before admission for stem cell harvesting. Clinical charts were reviewed for unexpected complications and unplanned admissions. Costs incurred were calculated using the value-driven-outcome (VDO) informatics analysis of the hospital.
Results
There were no unexpected clinical complications or unplanned admissions in both groups . The median length of hospital stay for the IP cohort was 3 days, amounting to a saving of 51 hospital days over 2 years in the OP cohort. Median costs were 73% lower in the OP cohort (Figure 3). The difference was mainly due to certain costs not incurred in the OP setting. These included room charges and daily treatment fees (which accounted for an average of 46% and 19% of IP charges respectively). Investigation costs were also 55% lower in the OP cohort, which could be attributed to more investigations being performed in the IP setting such as screening for methicillin-resistant Staphylococcus aureus and nonurgent radiographs ordered after hours by the on-call physician upon admission.
Conclusions
Our findings show that OP mobilization chemotherapy for MM is safe, feasible and associated with improved bed utilization and cost savings. Other components of the stem cell transplantation process are also increasingly being transitioned from the IP to OP setting in our center as part of an ongoing paradigm shift in right-siting treatment services, which has been accelerated by the COVID-19 pandemic's strain on inpatient capacity. These results provide an affirmation of our efforts to optimize the utilization of healthcare resources.
Figure 1 Figure 1.

Disclosures
Chng: Takeda: Consultancy; GlaxoSmithKline: Consultancy; Johnson & Johnson: Consultancy, Research Funding; Aslan: Research Funding; Antengene: Consultancy; Abbvie: Consultancy; Pfizer: Consultancy; Novartis: Research Funding; Sanofi: Consultancy; Amgen: Consultancy; BMS/Celgene: Consultancy, Research Funding.