A single subcutaneous injection of pegylated granulocyte colony-stimulating factor (Peg-G-CSF; pegfilgrastim) achieved rates of successful CD34-positive cell collection comparable to those with daily granulocyte colony-stimulating factor (G-CSF; filgrastim) for peripheral blood stem cell mobilization in healthy allogeneic hematopoietic stem cell transplantation (allo-HSCT) donors, according to data from a multicenter, randomized controlled trial (ChiCTR1800015716) published in Frontiers in Immunology.1
After a single apheresis, 83.3% of donors in the Peg-G-CSF group (n = 96) collected at least 4 × 10⁶ CD34-positive cells/kg of recipient body weight—the trial's primary end point compared with 79.2% in the G-CSF group (n = 96; P = .460). The median CD34-positive cell yield in the graft was 5.9 × 10⁶/kg (range, 1.5-43.3) with Peg-G-CSF vs 6.3 × 10⁶/kg (range, 1.5-23.6) with G-CSF (P = .987).
“Mobilization via a single injection of Peg-G-CSF can match traditional G-CSF mobilization in terms of efficacy and safety and is expected to provide a better alternative to traditional G-CSF mobilization,” lead study author Jiali Li, Sha Zhou, and colleagues wrote.
The authors are affiliated with the Medical Center of Hematology at the Second Affiliated Hospital of Army Medical University in Chongqing, China.
How was the mobilization trial designed?
The multicenter, open-label trial enrolled 192 healthy donors for patients with acute leukemia undergoing allo-HSCT and randomly assigned them 1:1 to receive either a single 12-mg subcutaneous injection of Peg-G-CSF on day 1 or G-CSF at 10 µg/kg per day beginning on day 1. Both agents were manufactured by Qilu Pharmaceutical. Eligible donors were 18 to 55 years of age, weighed 50 to 100 kg, had normal organ function, and were negative for infectious disease markers.
The primary end point was the percentage of donors who collected at least 4 × 10⁶ CD34-positive cells/kg of recipient weight after a single apheresis. Secondary end points included peripheral blood mobilization kinetics, graft composition, donor safety, and recipient transplant outcomes. The trial was conducted from May 2018 to April 2019, with a median recipient follow-up of 47 months (range, 1.1-93).
Single-Dose Peg-G-CSF vs Daily G-CSF for Donor Mobilization: Key Findings
- Single-injection Peg-G-CSF and daily G-CSF produced comparable rates of successful CD34-positive cell collection after one apheresis (83.3% vs 79.2%; P = .460).
- Median CD34-positive cell yields (5.9 vs 6.3 × 10⁶/kg) and overall adverse-effect rates (71.8% vs 74.2%) were similar between the arms.
- Recipient engraftment, GVHD, and 5-year survival outcomes did not differ significantly between the two donor-mobilization strategies.
What additional mobilization and graft data were reported?
On day 4 of mobilization, peripheral blood CD34-positive cell counts were higher with Peg-G-CSF than with G-CSF (47.7/µL vs 42.9/µL; P = .027), as were white blood cell counts (51.6 × 10⁹/L vs 41.2 × 10⁹/L; P < .01). By day 5, counts had peaked and were comparable between the arms, with CD34-positive counts of 60.1/µL vs 60.2/µL (P = .438). The median mononuclear cell yield in the graft was 10.3 × 10⁸/kg with Peg-G-CSF vs 9.7 × 10⁸/kg with G-CSF (P = .050).
Graft B-cell content was lower with Peg-G-CSF than with G-CSF (15.9 × 10⁹/L vs 18.9 × 10⁹/L; P = .047), whereas natural killer cells, regulatory T cells, and regulatory B cells did not differ significantly between the arms. In multivariate analysis, only the day-5 peripheral blood CD34-positive cell count independently predicted CD34-positive yield (P = .002).
How did transplant recipient outcomes compare?
Among the 192 recipients, the median time to neutrophil engraftment was 15 days in both arms, and the median time to platelet engraftment was 16 days with Peg-G-CSF vs 15 days with G-CSF. The 100-day cumulative incidence of any-grade acute graft-vs-host disease (GVHD) was 36.5% with Peg-G-CSF vs 39.7% with G-CSF (P = .560), and the cumulative incidence of chronic GVHD was 27.8% vs 36.0%, respectively (P = .360). Efforts to optimize allo-HSCT for patients with acute leukemia have also centered on conditioning intensity and GVHD control.2
The 5-year overall survival rate was 77.6% with Peg-G-CSF vs 70.6% with G-CSF (P = .246), and the 5-year progression-free survival rate was 57.9% vs 57.2% (P = .603). The 3-year non-relapse mortality rate was 6.76% with Peg-G-CSF vs 15.2% with G-CSF (P = .099), and the 3-year cumulative relapse incidence was 17.5% vs 15.5%, respectively.
What did the safety analysis show?
The overall incidence of adverse effects was 71.8% with Peg-G-CSF vs 74.2% with G-CSF (P = .624). Bone pain was the most common adverse effect, occurring in 67.7% of donors in the Peg-G-CSF arm vs 59.4% in the G-CSF arm and was mild in most cases; headache was reported in 42.7% vs 34.4%, respectively. Other effects included loss of appetite, fatigue, and sleeplessness.
Both agents were associated with transient increases in lactate dehydrogenase and alkaline phosphatase, and white blood cell counts recovered within 1 week in approximately 85% of donors in the Peg-G-CSF arm and 82% in the G-CSF arm. No serious adverse events, splenomegaly, or deaths attributed to mobilization were reported in either group.
References
- Li J, Zhou S, et al. Efficacy and safety of the single-dose pegylated G-CSF vs. daily G-CSF for peripheral blood stem cells mobilization in donors: a multicenter, randomized controlled trial. Front Immunol. 2026;17:1737252. doi:10.3389/fimmu.2026.1737252
- MBTF Before Allo-HSCT Produces Durable Efficacy and Manageable GVHD in R/R AML. OncLive. Published August 25, 2026. Accessed September 4, 2026. https://www.onclive.com/view/mbtf-before-allo-hsct-produces-durable-efficacy-and-manageable-gvhd-in-r-r-aml
