Forging a Treatment Path for Multiple Myeloma With ASCT

Multiple Myeloma: © David A Litman - stock.adobe.com

Stem cell collection in patients with newly diagnosed multiple myeloma (MM) undergoing anti-CD38 monoclonal antibody-based induction therapy is possible in both chemotherapy-based and steady-state protocols, but each carries their own burdens, according to a recent retrospective study.¹

Out of 42 steady-state and 48 chemotherapy-based mobilization attempts, there was no notable difference in the median concentration of CD34-positive (CD34+) cells in peripheral blood before apheresis (61/μL vs 55.4/μL; P = .60), and no difference was observed with or without plerixafor (Mozobil). A target yield of ≥4 × 106 CD34+ cells/kg body weight was achieved in 88% of the chemomobilization arm and 86% of the steady-state arm, with 76% and 75%, respectively, achieving the target yield after 1 apheresis session.

Of the 83 patients who underwent autologous stem cell transplantation (ASCT), all were engrafted, regardless of the mobilization protocol. Sex, disease subtype, previous radiation therapy, baseline plasma cell level, R-ISS stage, or timing of apheresis also did not appear to affect CD34+ cell concentration.

Previous findings have held that chemomobilization delivers superior yield rates²; however, this study’s findings present the need for further trials to evaluate this issue more fully and precisely.

Median collection efficiency was also consistent between groups, with the steady-state arm at 46.7% (range, 16.7%-73.9%) and chemomobilization arm at 45.6% (range, 17.2%-79.7%; P =.43).¹ The median graft total cell count was higher in steady-state collections compared with chemomobilization (763 × 108 v 379 × 108; P < .01), respectively.

Before apheresis, 82% of patients had already achieved a very good partial response (VGPR) or better, and the remaining 18% had a less deep response by International Myeloma Working Group criteria. Higher CD34+ counts were observed in patients with a VGPR, with a median of 63.0 μL in patients with a VGPR vs 45.0 μL in patients without.

In the steady-state arm, plerixafor was used in 57% of patients compared with 23% in the chemomobilization arm (P <.01) and was more often given as a preemptive treatment rather than in response to the first apheresis. While the administration of plerixafor adds to treatment costs, steady-state mobilization still has some advantages over chemomobilization.

“The more common application of plerixafor in the steady-state cohort clearly carries an extra financial burden. However, steady-state mobilization does not require an inpatient stay and offers better scheduling of stem cell collections, reducing the necessity of performing the collections on weekends. These factors may outweigh the higher costs associated with more frequent use of plerixafor,” according to the authors of the study published in Transfusion.

Plerixafor can be administered up to 4 consecutive days with a maximum administration of 40 mg or 2 vials per day.^3,4A study from the Zheijang University School in Zheijang, China found that even 1 vial of plerixafor throughout the entire mobilization process yielded a higher success rate and quicker apheresis times, partially minimizing the financial burden while maintaining mobilization benefits.⁵

“New cellular treatment options in MM, including chimeric antigen receptor (CAR) T-cell therapy and bispecific antibodies, are leading to profound changes in the treatment landscape of relapsed/refractory myeloma. Currently, enrolling clinical trials have begun to study CAR T-cells and bispecific antibodies in the context of frontline treatment. It will be of particular interest if these new therapeutic options lead to a practice change in transplant-eligible patients, especially regarding the necessity of a (tandem) ASCT. This could eventually lead to a reduction of ASCT and reduce target collection goals accordingly,” study authors wrote.¹

REFERENCES:

1. Teipel R, Rieprecht S, Trautmann-Grill K, et al. Steady-state versus chemotherapy-based hematopoietic cell mobilization after anti-CD38-based induction therapy in newly diagnosed multiple myeloma. Transfusion. 2023; 63(11): 2131–2139. doi:10.1111/trf.17566

2. Hübel K. Mobilization and Collection of HSC. In: Carreras E, Dufour C, Mohty M, et al., editors. The EBMT Handbook: Hematopoietic Stem Cell Transplantation and Cellular Therapies [Internet]. 7th edition. Cham (CH): Springer; 2019. Chapter 15. doi:10.1007/978-3-030-02278-5_15

3. Plerixafor (Rx). Medscape. Accessed November 20, 2023. https://tinyurl.com/4kznakuu

4. Plerixafor prices, coupons and patient assistance programs. Drugs.com. Accessed November 20, 2023. https://tinyurl.com/28jrnvxv

5. Han X, Huang X, Zheng G, et al. Application of first-line steady-state mobilization vs. conventional chemotherapy mobilization for peripheral hematopoietic stem cell mobilization in newly diagnosed multiple myeloma patients. ClinOncol. 2022;7(1):1977. doi:10.25107/24741663