Work

Plerixafor Dosing in Obese Patients with Multiple Myeloma: A Single Center Experience

Year: 2025

Type: article

Abstract: Introduction Plerixafor , an inhibitor of CXCR4 chemokine receptor , is frequently given to patients with multiple myeloma (MM) for mobilization prior to autologous hematopoietic cell transplantation (HCT). Standard weight-based dosing is 0.24 mg/kg daily for up to 4 days with a maximum dose of 40 mg/day. Current practice at Moffitt Cancer Center is to administer a fixed (capped) dose of 24 mg in patients weighing more than 100 kg, however some patients received standard (higher) doses according to the label instructions. The optimal strategy for higher weight patients has not been defined. Here, we describe our experience and mobilization outcomes in a large MM HCT population, comparing those patients who received capped dosing (CD) and standard full dosing according to label (SD). Methods All consecutive MM patients weighing over 10 kg who received plerixafor between 2015 and 2023 were included in our analysis. Data collection included the following: disease state, age, gender, height, weight, serum creatinine, number of CD34 cells collected, GCSF dose, number of GCSF doses administered, plerixafor dose, and number of plerixafor doses administered. In patients weighing greater than 100 kg, comparisons were made between CD and SD patients. The final outcome for each group was successful collection, defined as meeting the target of greater than 4 × 10 6 CD34+ cells/kg. Results From 2015 to 2023, 177 patients were greater than 102 kg (Table 1). The majority received capped doses (n=161) while 16 patients received standard weight-based dosing. Most were male (78.5%), with a median age of 60 years (range, 32-74 years), and a median actual body weight of 113.8 kg (range, 102.1-161.9 kg). In SD patients, plerixafor doses varied from 25 mg to 40 mg/day (Table 2). The median number of plerixafor doses were similar between CD and SD patients (1 day, range 1-4, vs 1 day, range 1-2, respectively). The median number of apheresis collection days between groups was similar (CD 1 day, range 1-4, vs SD 1 day, range 1-2; respectively). In CD patients, the median final CD34 million cells/kg count was 6.18 (2.06 – 17.3). In the SD patients, the median final CD34 million cells/kg count was 5.93 (2.48 – 19.3). Regarding the proportion of successful collections, 95.7% of the CD patients and 100% of the SD patients achieved goal collection ( p =1) (Table 3). Conclusion We report plerixafor dosing on a large cohort of MM patients weighing greater than 102 kg undergoing apheresis prior to HCT. Our results indicate that our current strategy of capping plerixafor doses in patients above 102 kg results in similar collection outcomes to those who receive standard full weight-based dosing.

Source: Transplantation and Cellular Therapy

DOI: 10.1016/j.jtct.2025.01.299