This study evaluates the effectiveness and safety of PEG-rhG-CSF injection for the reconstruction of neutrophil cells after autologous hematopoietic stem cell transplantation in lymphoma/multiple myeloma patients.

This study is a single-center, open-label clinical trial. Inclusion criteria involve patients with confirmed lymphoma or multiple myeloma receiving autologous hematopoietic stem cell transplantation for the first time. After calculating the sample size, an initial cohort of 40 trial patients is expected to be enrolled. Patients meeting the eligibility criteria will be assigned to receive PEG-rhG-CSF treatment on the second day after hematopoietic stem cell infusion, with a fixed dose of 6 mg. The primary outcome measure of this study is the median time for neutrophil cell reconstruction. Secondary study endpoints include safety indicators of the medication, the duration of neutrophil cell reduction (ANC≤2.0×10^9/L), the number of days patients spend in the laminar flow ward after transplantation, the usage of antibiotics, antifungal, or antiviral drugs, as well as patient expenditures, among other indicators.

Criteria for withdrawal/discontinuation of treatment:

(1) Subjects voluntarily request to withdraw from the trial;(2) Subjects who, although not explicitly requesting withdrawal from the trial, no longer adhere to the trial protocol for treatment and assessments, resulting in loss to follow-up; (3) Subjects with poor compliance who switch treatment regimens midway or use prohibited drugs within the protocol; (4) Subjects who were incorrectly enrolled; (5) Subjects experiencing intolerable allergic reactions or adverse events; (6) Subjects who pass away; (7) Other situations that meet the exclusion criteria arise.

Management of detachment cases:

When patients withdraw from the study due to allergic reactions or adverse events, researchers should take appropriate treatment measures based on the subject's condition. For mid-study withdrawal or loss to follow-up, researchers should actively take measures to complete the final assessment to analyze their efficacy and safety. All dropout cases should be documented in the case report form, and the trial conclusion form should be filled out along with the reasons for the subject dropout.

Inclusion Criteria:

1. Age 18-65, any gender;
2. Patients with lymphoma/multiple myeloma requiring autologous hematopoietic stem cell transplantation;
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 before transplantation;
4. Basic normal function of heart, lungs, liver, and kidneys (no severe heart disease, no severe lung disease; transaminases ≤ 3× upper limit of normal, blood bilirubin ≤ 2.0 mg/dl; blood creatinine ≤ 2× upper limit of normal);
5. Pre-transplant blood counts meet the following criteria: ANC (Absolute Neutrophil Count) ≥ 1.5×10^9/L, HGB (Hemoglobin) ≥ 90g/L, PLT (Platelets) ≥ 100×10^9/L;
6. No other severe diseases that conflict with this protocol;
7. Expected survival of ≥ 3 months and willingness to follow-up;
8. Voluntary participation in this clinical trial and signing of informed consent;
9. The investigator believes that the subject will benefit from participation.

Exclusion Criteria:

1. Patients with splenomegaly;
2. Individuals who have previously undergone allogeneic or autologous hematopoietic stem cell transplantation;
3. HIV antibody-positive, HbsAg-positive, or HCV antibody-positive;
4. Impaired liver or kidney function (transaminases >3× ULN or blood bilirubin >2.0 mg/dl; blood creatinine >2× ULN);
5. Decompensated heart failure, dilated cardiomyopathy, coronary artery disease with ST-segment depression on electrocardiogram, or myocardial infarction within the last Six months;
6. Clinical symptoms of cognitive impairment or severe mental illness;
7. Allergic reactions to polyethylene glycol recombinant human granulocyte colony-stimulating factor injection or recombinant human granulocyte colony-stimulating factor injection;
8. Pregnant or breastfeeding women;
9. Investigators believe participation in this clinical trial is unsuitable.