CHRONO-MOBILIZE: Chronotherapy of G-CSF for CD34+ Mobilization in Healthy Donors (CHRONO-MOBILIZ)

Effect of Different Administration Timing of G-CSF on Peripheral Blood CD34+ Cell Mobilization in Healthy Donors: A Prospective Multicenter Randomized Controlled Trial

Healthy donors are commonly mobilized with granulocyte colony-stimulating factor (G-CSF) to collect peripheral blood stem cells for allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the efficiency of mobilization varies among donors, and suboptimal mobilization may require additional collection procedures or rescue strategies.

This prospective, multicenter, randomized trial evaluates whether the timing of daily G-CSF administration (morning vs evening) affects the level of circulating CD34+ cells prior to apheresis in healthy donors. Participants will be randomly assigned to receive subcutaneous G-CSF 10 μg/kg once daily for 5 consecutive days either at 08:00 (±15 minutes) or at 20:00 (±15 minutes). The primary endpoint is the peripheral blood CD34+ cell count measured approximately 12 hours after the last G-CSF dose and within 60 minutes before the start of the first apheresis session. Secondary endpoints include collection efficiency and CD34+ yield metrics, the proportion of donors achieving the target CD34+ dose on the first collection day, the need for a second collection day, and donor safety outcomes.

The goal of the study is to identify a practical dosing schedule that may improve stem cell mobilization and streamline donor collection procedures.

Study Overview

• Status: Not yet recruiting
• Conditions: Granulocyte Colony-Stimulating Factor (G-CSF) Mobilization
• Intervention / Treatment: Drug: G-CSF (Granulocyte colony-stimulating factor)

Detailed Description

Background and Rationale

Peripheral blood stem cell collection after G-CSF mobilization is the most widely used donation approach for allo-HSCT. Donor mobilization outcomes exhibit inter-individual variability, and donors with lower circulating CD34+ levels may require longer processing volumes, additional collection days, or rescue mobilization. Circadian biology may influence hematopoietic cell trafficking and cytokine responses, suggesting that the administration timing of G-CSF could affect mobilization intensity and collection efficiency. This trial tests whether a simple, operational change in dosing time can improve pre-apheresis CD34+ levels in healthy donors.

Objectives

Primary Objective: To compare the pre-apheresis peripheral blood CD34+ cell count between donors receiving G-CSF in the morning versus the evening.

Secondary Objectives: To compare collection efficiency and CD34+ yield measures, the need for additional collection days, target attainment on day 1, and donor safety outcomes between study groups.

Study Design

This is a prospective, multicenter, stratified randomized controlled trial with two parallel arms. The study is open-label due to the nature of the intervention (fixed dosing times), while the statistician will remain blinded to group allocation until database lock.

Randomization is conducted via a central interactive web response system (IWRS) using block randomization. Allocation is stratified by donor age (<40 vs ≥40 years) and sex to balance key donor characteristics across arms.

Interventions and Procedures

Eligible healthy donors will receive subcutaneous G-CSF at 10 μg/kg once daily for 5 consecutive days (Day 1 to Day 5), assigned to one of the following schedules:

Morning group: 08:00 (±15 minutes) each day

Evening group: 20:00 (±15 minutes) each day

The first apheresis session is scheduled to begin approximately 12 (±1) hours after the final G-CSF dose, and the primary endpoint blood sample is obtained within 60 minutes prior to the start of apheresis. Collection targets are based on recipient weight, with standard operational procedures for conducting a second collection day if the first-day yield does not meet the target. If peripheral blood CD34+ is low after the final G-CSF dose, centers may apply rescue mobilization per local practice, and such use will be recorded for sensitivity analyses.

Outcome Measures

Primary Outcome: Peripheral blood CD34+ cell count (cells/μL) measured approximately 12 (±1) hours after the last G-CSF dose and within 60 minutes before the first apheresis session, assessed by standardized flow cytometry procedures.

Key Secondary Outcomes:

Collection efficiency (CE2)

CD34+ yield normalized to processed blood volume

Proportion of donors achieving the target CD34+ dose on the first collection day

Need for a second collection day

Donor safety outcomes, including adverse events during mobilization, collection, and follow-up

Sample Size and Analysis Overview

A total of 160 donors (80 per group) will be enrolled to provide adequate power for detecting clinically meaningful differences in the primary endpoint while allowing for non-evaluable cases. The primary analysis will follow the intention-to-treat principle, with additional per-protocol and sensitivity analyses as appropriate, including analyses accounting for rescue mobilization when applicable.

Safety Monitoring and Follow-up

Donors will be monitored with clinical assessment and routine laboratory testing during the mobilization period and on collection days. Adverse events commonly associated with G-CSF (e.g., bone pain) and donation-related events will be recorded and managed per standard-of-care practices. Donors will be followed through approximately Day 30 to capture delayed or persistent adverse events.

• Study Type: Interventional
• Enrollment (Estimated): 160
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hengwei Wu, MD; Phone Number: +8619858162455; Email: cctv3194495@163.com

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310000
      • The First Affiliated Hospital of Zhejiang University School of Medicine
      • Contact: Hengwei Wu; Phone Number: 19858162455; Email: wuhengwei@zju.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Age 18-55 years
2. HLA matching appropriate for intended allo-HSCT recipient and meets donor medical evaluation criteria
3. Body weight ≥35 kg and adequate blood volume/BSA for apheresis
4. Karnofsky score ≥80
5. Screening labs meet thresholds (Hb/platelets/ANC, liver/renal/coagulation), no splenomegaly, pregnancy test negative if applicable
6. Written informed consent
7. Stable circadian rhythm before mobilization (no night shift/no ≥3 time-zone travel; avoid melatonin/sedatives or other agents affecting sleep/circadian rhythm)

Exclusion Criteria:

1. Prior/current hematologic or immune diseases (e.g., aplastic anemia, leukemia, lymphoma, autoimmune disease)
2. Significant cardiovascular/structural heart disease, uncontrolled hypertension, uncontrolled diabetes
3. Neurologic/psychiatric disorders affecting adherence
4. Sleep/circadian disorders; recent night shift or ≥3 time-zone travel
5. Prohibited medications (e.g., beta-blockers, systemic steroids >10 mg prednisone-equivalent ≥7 days, melatonin/psychotropics; recent G-CSF/GM-CSF/CXCR4 inhibitor use)
6. Severe allergy to G-CSF or components

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Morning G-CSF Dosing; 10 μg/kg subcutaneous once daily for 5 days at 08:00 ± 15 min	Drug: G-CSF (Granulocyte colony-stimulating factor); Subcutaneous recombinant human G-CSF (10 μg/kg once daily) administered for 5 consecutive days. Participants are assigned to a fixed dosing time: 08:00 (±15 minutes) or 20:00 (±15 minutes). Peripheral blood CD34+ is measured approximately 12 (±1) hours after the last dose and within 60 minutes before the first apheresis. The first apheresis begins ~12 (±1) hours after the final G-CSF dose. A second collection day may be performed per standard practice if the first-day yield does not meet the target; rescue mobilization (e.g., plerixafor) may be used per center practice when pre-defined low CD34+ criteria are met and will be recorded.
Experimental: Evening G-CSF Dosing; 10 μg/kg subcutaneous once daily for 5 days at 20:00 ± 15 min	Drug: G-CSF (Granulocyte colony-stimulating factor); Subcutaneous recombinant human G-CSF (10 μg/kg once daily) administered for 5 consecutive days. Participants are assigned to a fixed dosing time: 08:00 (±15 minutes) or 20:00 (±15 minutes). Peripheral blood CD34+ is measured approximately 12 (±1) hours after the last dose and within 60 minutes before the first apheresis. The first apheresis begins ~12 (±1) hours after the final G-CSF dose. A second collection day may be performed per standard practice if the first-day yield does not meet the target; rescue mobilization (e.g., plerixafor) may be used per center practice when pre-defined low CD34+ criteria are met and will be recorded.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pre-Apheresis Peripheral Blood CD34+ Cell Count	Peripheral blood CD34+ cell count (cells/µL) measured by flow cytometry (ISHAGE single-platform method). Blood is drawn approximately 12 (±1) hours after the last G-CSF dose and within 60 minutes before the start of the first apheresis session.	On the day of first apheresis: approximately 12 (±1) hours after the final G-CSF dose and within 60 minutes prior to apheresis start.

Collaborators and Investigators

• Sponsor: First Affiliated Hospital of Zhejiang University
• Collaborators: Tongji Hospital; Ruijin Hospital; The First Affiliated Hospital of Zhengzhou University; The Children's Hospital of Zhejiang University School of Medicine; Union Hospital, Tongji Medical College, Huazhong University of Science and Technology

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 30, 2027

Study Registration Dates

• First Submitted: February 13, 2026
• First Submitted That Met QC Criteria: February 19, 2026
• First Posted (Actual): February 20, 2026

Study Record Updates

• Last Update Posted (Actual): February 20, 2026
• Last Update Submitted That Met QC Criteria: February 19, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: G-CSF; Allo-HSCT; CD34
• Additional Relevant MeSH Terms: Peptides; Amino Acids, Peptides, and Proteins; Proteins; Biological Factors; Carbohydrates; Intercellular Signaling Peptides and Proteins; Glycoproteins; Glycoconjugates; Colony-Stimulating Factors; Hematopoietic Cell Growth Factors; Cytokines; Granulocyte Colony-Stimulating Factor
• Other Study ID Numbers: ZJUFAH-CHRONOMOB

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared because the study involves healthy donors and contains potentially identifiable information. De-identified, aggregate results will be reported in publications and presentations. Reasonable requests for additional information may be considered by the study team on a case-by-case basis, subject to ethics approval and data governance requirements.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No