Presenting Authors: Hoim Kim, PharmD, BCOP, BCPS, City of Hope National Medical Center, Duarte, CA; Shelley Chang, MD, PhD, University of Southern California School of Medicine, Los Angeles, CA
Co-Authors: Shan Yuan, MD, and Shirong Wang, MD, City of Hope National Medical Center, Duarte, CA
BACKGROUND: Plerixafor is an adjunct agent for peripheral blood stem cell (PBSC) mobilization with well-demonstrated safety and efficacy since its FDA approval in 2009. Until recently, plerixafor was solely available in the United States under the brand name of Mozobil (Sanofi-Aventis; France), and its widespread use has been limited by cost. Our institution recently switched from using Mozobil to generic plerixafor (Meitheal Pharmaceuticals; Chicago, IL) with a much lower cost.
OBJECTIVE: This retrospective, observational study was conducted to compare the mobilization efficacy of generic and brand-name plerixafor in patients with multiple myeloma (MM).
METHODS: Two cohorts of consecutive patients with MM who underwent PBSC mobilization immediately before (n=64) and after (n=61) the switch from brand-name to generic plerixafor were identified. All were mobilized with filgrastim at 10 µg/kg/day for 4 days, with plerixafor given subcutaneously either upfront in the evening of day 4 prior to starting collection on day 5 or added just in time on day 5 following low peripheral blood CD34 counts or collection yields. Injections and apheresis collections continued until 2-3 × 10e6 or 4-6 × 10e6 CD34+ cells/kg for single and double transplant candidates, respectively, were collected.
RESULTS: The 2 cohorts had no significant difference in sex (brand-name, 65.5% male; generic, 60.7% male; P=.70), median age (brand-name, 61.5; generic, 64; P=.30), and mean weight (brand-name, 82 kg; generic, 86.86 kg; P=.20), previous radiation therapy (brand-name, 14.1%; generic 9.84%; P=.59), previous number of therapy lines (brand-name: 70% 1 line, 28.1% 2 lines, 1.56% 3 lines; generic: 67.2% 1 line, 32.8% 2 lines, 0% 3 lines; P=.70), upfront (vs just-in-time), or plerixafor use (brand-name, 62.5%; generic, 73.8%; P=.250). Patients required a lower median number of plerixafor doses and collection days in the generic arm (1; interquartile range [IQR], 1-2) versus brand arm (2; IQR, 1-2; P<.05). Only 31% of patients in the generic arm required more than 1 dose versus 59% of patients in the brand-name arm (P<.05). There is a significantly higher post-plerixafor day-1 yield (10e6 CD34+ cells/kg) in the generic versus brand-name cohorts (4.79 vs 3.78, respectively; P<.05). There were no significant differences in the median total yield after treatment with plerixafor (brand-name, 5.38; generic 5.47; P=.441) and the median overall cumulative total yield (brand-name, 5.91; generic, 5.80; P=.505). Only 4.69% and 3.28% in the brand-name and generic cohorts did not collect 2 × 10e6 CD34+ cells/kg (P=1).
CONCLUSION: Generic plerixafor produced similar cumulative collection yields with fewer doses and collection days compared to brand-name plerixafor.
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