ORLANDO – Collecting and storing extra stem cells on the off chance that a patient with multiple myeloma will need a salvage autologous stem cell transplant may not be worth the money or effort, investigators say.
Among patients with multiple myeloma who had adequate collection of mobilized and stored cells, only 3 of 146 eligible patients were given the stored cells in a second autologous stem cell transplant (ASCT), reported, from the Case Western Reserve Cancer Center and University Hospitals Seidman Cancer Center, both in Cleveland.
“We found overall low utilization of salvage transplants and storage stem cells at our institution, which may not justify the strategy of early collection for all patients fit for transplant,” she said at the Transplantation and Cellular Therapy Meetings.
Get them while they’re fresh
The rationale for collecting and storing extra cells is the risk that mobilization will fail in the future following prolonged maintenance with immunomodulatory agents such as lenalidomide (), and the risk for genetic or epigenetic damage to cells from high-dose melphalan used in transplant-conditioning regimens, Dr. Ahmed noted at the meeting held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research.
“However, there are potential issues with early mobilization and storage, including cost, resources, apheresis scheduling, uncertainty of cell viability, and liability. There’s also risk of side effects with filgrastim and plerixafor use [for mobilization],” she said.
Dr. Ahmed and colleagues conducted a study to determine how stored stem cells for second ASCT were used, describe how second ASCTs are used in patients who meet the Mayo Consensus Stratification for Myeloma & Risk-Adapted Therapy () criteria, and the costs of mobilizing and storing stem cells for a second ASCT.
They took a retrospective look at all adults aged 18 years and older with a diagnosis of multiple myeloma who received a first ASCT at their institution from 2009 to 2017. They excluded patients who had amyloidosis without myeloma or(polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma proliferative disorder, skin changes) syndrome.
Patients were considered eligible for a second ASCT based on mSMART recommendations if they had a relapse either 18 or more months without maintenance therapy or after at least 36 months on maintenance. The investigators defined an extra day of collection as an additional day of apheresis to obtain 2 million or more CD34 cells/kg for storage only.
They estimated costs from the institution’s charge master as the sum of cell processing, leukapheresis costs, additionalcosts, and storage costs, and calculated the total duration of storage as months from the date of collection until the last follow-up.
The median age of the total study population of 179 patients was 61 years, with a majority of male and white patients. Of this group, 98% had an Eastern Cooperative Oncology Groupof 0-1. In all, 63.7% of the patients had standard-risk cytogenetics, 22.4% had high-risk disease, and the remainder had unknown cytogenetic risk.
At a median follow-up of 56.5 months, 95 patients (53.1%) had experienced a relapse after transplant with a median time to progression of 47.5 months. The majority of patients (166; 92.7%) had received a single transplant, 10 (5.6%) had received tandem transplants, and only 3 (1.6%) had a second transplant at relapse.
Looking at the use of second transplant in patients who met the criteria for salvage transplant based on mSMART (excluding patients who had undergone tandem transplant) and whose maintenance status was known, they identified 61 patients on maintenance therapy and 24 with no maintenance. A total of 31 patients (18 in the maintenance group and 13 in the no-maintenance group) met mSMART criteria for salvage ASCT.
Dr. Ahmed and colleagues next looked at the 146 patients who had at least 2 million stored cells/kg, and found that the stored cells were used for only three patients. Of the 146 patients, 66 had 1 extra collection day, 17 had 2 extra days, and 4 had 3 extra days, for an average additional cost per patient of $16,859.