Successful treatment of marrow failure after CARTs for myeloma by the infusion of cryopreserved stem cells

tional study to determine risk factors of venous thromboembolism in patients with multiple myeloma treated with immunomodulatory drugs. Thromb Haemost. 2013;110(4):844-851. 5. Chalayer E, Tardy-Poncet B, Karlin L, et al. Thrombin generation in newly diagnosed multiple myeloma during the first three cycles of treatment: An observational cohort study.Res Pract ThrombHaemostasis. 2019;3(1):89-98. 6. Chalayer E, Chapelle C, Leleu X, Elalamy I, Laporte S, Tardy B. Does the choice of thrombotic prophylactic drug depend on the known risk factors of patients with multiple myeloma in clinical practice? Thromb Res. 2016;143:101-102.


Successful treatment of marrow failure after CARTs for myeloma by the infusion of cryopreserved stem cells
To the Editor: Chimeric antigen receptor transduced T cell (CART) therapy has demonstrated clinical activity in multiple malignant tumors. 1 In 2017, the United States Food and Drug Administration approved CD19-targeted CART cells (CARTs) as a salvage treatment for recurrent and/or refractory patients with B cell malignancies. 2,3 In recent years, several CART clinical trials for multiple myeloma (MM) conducted worldwide have shown good clinical response, with target antigens including BCMA, CD19, and others. [4][5][6][7][8][9] In addition to the clinical efficacy of CART therapy, it is important to pay attention to the possible adverse reactions, to reduce the severe, irreversible treatment-related mortality and to ensure that toxicity is managed well. Prolonged pancytopenia should also be a focus beyond unique acute cytokine release syndrome (CRS). 1 Such complications may bring the risk of fatal infection and bleeding, and could increase the hospital stay and economic burden of patients. Here, we report one patient with relapsed and refractory MM who developed bone marrow failure and severely prolonged pancytopenia after receiving sequential CD19and BCMA-specific CARTs. His hematopoiesis was successfully restored by the infusion of cryopreserved autologous stem cells.
Case presentation: A 41-year-old male was diagnosed multiple myeloma with IgG lambda in March 2018 after presenting with anemia, mildly elevated creatinine and multiple bone lesions. He received induction therapy with four cycles of bortezomib, thalidomide and dexamethasone (BTD), which resulted in maximum efficacy of partial remission according to the International Myeloma Working Group (IMWG) response criteria. 10 At this time, the patient was determined to have developed the complication of grade 2 peripheral neuropathy with pain. Autologous stem cells were collected after the administration of high-dose cyclophosphamide However, the response was poor, and the disease continued to progress.
In September 2018, high-dose conditional chemotherapy (busulfan 9.6 mg/m 2 and cyclophosphamide 3.6 g/m 2 ) was followed by salvage ASCT. The graft for ASCT was half the amount of the collection. The ASCT resulted in stable disease for 2 months. Considering this poor prognostic finding, the patient was later enrolled in the reported CART trial in our center in December 2017. 11 A bone marrow aspirate showed weak CD19 expression (0.08%) and strong positive BCMA expression (94.5%) on the clonal plasma cells by flow cytometry. The patient's treatment and administration schedule is shown in Figure 1A.
The patient presented a fever of 38.8°C ten hours after infusion of the first dose of CARTs-CD19, and the peak of temperature was 39.8°C on day two, and lasted for a total of 9 days. The peak serum ferritin level was also nearly four times higher compared to the baseline ( Figure 1B This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. stem cells, containing 3.05*10 6 /kg CD34-positive cells, were infused considering the limited value of tandem ASCT. As expected, the patient's hematopoietic function was gradually reconstructed on the 11th day after infusion of autologous stem cells ( Figure 1D).
The trends of the patient's serum IgG concentration and the serum monoclonal protein concentration (M spike) throughout the treatment are shown in Figure 1E. The serum monoclonal protein became undetectable 4 months postinfusion and remained undetectable until July 2019. After CART therapy, bone marrow aspirate and biopsy also confirmed that the patient achieved stringent complete remission ( Figure 1F), including minimal residual disease negative by flow cytometry. The laboratory characteristics of the patient's bone marrow before and after CART treatment are shown in Table 1. The CARTs maximum amplified 16.34-fold on day eight postinfusion, and sustained for 29 days by quantitative PCR using a transgene-specific primer/probe pair.
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Note, CART therapy is associated with unique CRS toxicities.
Higher peak in vivo proliferation of CARTs is possibly associated with a clinical response, but it has also been associated with CRS grade. 3,14,15 Thus, CRS is an inflammatory syndrome caused by multiple cytokines produced by the CARTs themselves and by other cells, and can induce damage to multiple systems, including the hematopoietic system.

CONFLICT OF INTEREST
All authors declare that they have no conflicts of interest. The research protocol referenced in this manuscript has been approved by the Ethics Committee of the First Affiliated Hospital of Soochow The treatment medication protocol and clinical and laboratory parameters relative to the timing of CART therapy. A, Chemotherapy for lymphocyte depletion included fludarabine and cyclophosphamide. CARTs were infused at a single 1 × 107/kg dose of CD19-CARTs on day 01 and a split-dose of BCMA-CARTs infusion, 40% on day 02 and 60% on day 03 (total 5 × 107/kg dose). B, The patient's temperature rapidly rose post-CARTs, and his serum ferritin level gradually rose to reach a peak level on day 4 post-CARTs. The red line represents the patient's maximum temperature in degrees centigrade (°C) per 24-hour period, with squares demarcating each day. The black line represents the patient's serum ferritin in ng/mL, with circles showing tested values each day. Both parameters returned to baseline on day 9 post-CARTs. C, The trends of IL-6, IL-10 and IFNγ concentrations are shown during the course of CART therapy. The red line represents the patient's serum IL-6 concentration (pg/ml), with circles showing tested values each day. The black line represents the patient's IL-10 concentration in pg/mL with squares representing the tested values each day. The blue line represents the patient's IFNγ concentration in pg/mL, with triangles showing the tested values each day. Time on vasoactive medications (norepinephrine) is indicated by a black line under "vasoactives" (days 03 to 8). D, The trends of blood cell count are exhibited during and after CART treatment. The black, red, blue and green lines respectively represent the levels of white blood cells, hemoglobin, platelets and neutrophils. The initiation of each treatment regimen is depicted by an arrow. E, IgG and serum M protein levels are shown throughout the treatment course. The initiation of each treatment regimen is depicted by an arrow. F, Hematoxylin and eosin staining and immunohistochemical (IHC) staining for CD138. Bone marrow cells were 50% clonal plasma cells, as shown by CD138 staining before CARTs infusion (original magnification, × 100). Bone marrow examination showed severe aplastic cellularity, and no plasma cells could be detected 1 month post-CARTs T A B L E 1 Laboratory characteristics of the patient's bone marrow before and after CART treatment