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Plerixafor, G-CSF may serve as preferred stem cell mobilization for multiple myeloma
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The use of cyclophosphamide or plerixafor, in combination with granulocyte colony–stimulating factor, facilitated robust stem cell mobilization in patients with multiple myeloma, according to data presented at the BMT Tandem Meetings.
However, the combination of plerixafor (Mozobil, Genzyme) and G-CSF appeared better tolerated and had a more predictable course, which suggested that it should be considered the preferred stem cell mobilization regimen, according to the researchers.
Chemomobilization with cyclophosphamide serves as the most common regimen for stem cell mobilization in patients with multiple myeloma, according to study background. However, recent studies have suggested that plerixafor and G-CSF may be equally effective, if not superior, in this patient population.
Thus, Carlyn Rose C. Tan, MD, fellow in training at Fox Chase Cancer Center, and colleagues sought to compare the safety and efficacy of both mobilization regimens.
The researchers evaluated data from 80 patients who underwent stem cell mobilization at their institution between January 2012 and May 2015. All but one patient went on to receive high-dose melphalan (Alkeran, GlaxoSmithKline) with autologous stem cell transplant.
Thirty-five patients received cyclophosphamide (3 gm/m2) on day 1, followed by G-CSF on day 2. The other 45 patients received G-CSF on day 1, followed by plerixafor (0.24 mg/kg per day) beginning on day 4.
The researchers evaluated apheresis on day 12 of treatment in patients treated with cyclophosphamide and on day 5 for patients treated with plerixafor. They measured demographics, CD34-positive cell yield on day 1, total CD34-positive cell yield, toxicities and time to engraftment.
On day 1, both groups had similar median CD34-positive cell yield (cyclophosphamide, 10.6; plerixafor, 8.65) and median total yield (cyclophosphamide, 10.6; plerixafor, 8.7).
The researchers observed one poor mobilizer (< 2 x 106 cells per kg in ≤ 3 aphereses) in the cyclophosphamide arm and none in the plerixafor arm.
Comparable numbers of good mobilizers (≥ 5 x 106 cells per kg in ≤ 2 days; 32 vs. 42) and rapid mobilizers (≥ 4 x 106 cells per kg on day 1; 32 vs. 40) were seen in both arms.
Eighty-three percent of patients treated with cyclophosphamide and 87% of patients treated with plerixafor completed stem cell mobilization in one treatment session.
However, treatment with cyclophosphamide and G-CSF appeared associated with significantly higher rates of severe neutropenia (86% vs. 0; P < .001), hospitalization (11% vs. 0; P = .02) and delay in apheresis (14% vs. 0; P = .009).
Additionally, five patients treated with cyclophosphamide developed febrile neutropenia, compared with none treated with plerixafor.
Patients treated with cyclophosphamide had a mean time to neutrophil recovery (10.8 vs. 11.4; P = .005); however, platelet recovery did not significantly differ (13.6 vs. 15).
“Our next step is to evaluate the cost-effectiveness of these two mobilization regimens and to look into any differences in outcomes based on the mobilization regimen used,” Tan told HemOnc Today. “Given its effectiveness, safety profile and predictable course, upfront plerixafor/G-CSF may be considered the preferred mobilization regimen for multiple myeloma patients.” – by Cameron Kelsall
Reference:
Tan CRC, et al. Abstract 160. Presented at: BMT Tandem Meetings; Feb. 18-22, 2016; Honolulu.
For more information:
Carlyn Rose C. Tan, MD, can be reached at carlyn.tan@fccc.edu.
Disclosure: HemOnc Today was unable to confirm the researchers’ relevant financial disclosures at the time of reporting.