This is a prospective, single-arm, multi-center, phase II clinical study to evaluate the efficacy and safety of Trilaciclib in DLBCL patients treated with R-CHOP.

This is a prospective, single-arm, multi-center, phase II clinical study to investigate the myeloprotection efficacy, antitumor efficacy, and safety of Trilaciclib in DLBCL patients treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin or Epirubicin, vincristine, and prednisone). 38 eligible subjects who met the inclusion criteria were screened and given a treatment regimen of Trilaciclib before chemotherapy R-CHOP, after signing informed consent. The incidence of Grade ≥ 3 neutropenia was used as the primary endpoint to observe whether Trilaciclib could reduce the occurrence or degree of chemotherapy-induced myelosuppression (CIM). Researchers will monitor potential adverse events (AEs) throughout the entire trial and grade the severity of adverse events according to the guidelines of the National Cancer Institute (NCI) Common Terminology for Adverse Events (CTCAE) 5.0.

Inclusion Criteria:

1. Having sufficient understanding of this study and being willing to sign the informed consent form (ICF);
2. Age above 18 years old (including 18 years old)，regardless of gender;
3. Treatment-naive, histologically confirmed DLBCL, at least one tumor lesion that could be measured accurately at baseline according to RECIST1.1 criteria;
4. IPI score 0-2;
5. ECOG score of 0-2；
6. No prophylactic G-CSF, TPO, IL-11, ESA, iron within 1 week of screening hematology test, and no platelet transfusion or blood transfusion；
7. Estimated survival greater than 3 months；
8. Adequate organ function；
9. Being willing and able to comply with the visits, treatment plan, laboratory examinations and other study procedures scheduled in the study;
10. Women of childbearing potential must undergo a serum pregnancy test within 3 days prior to the first dose and the result must be negative. Female patients of childbearing potential and male subjects whose partners are women of childbearing potential must agree to use highly effective contraceptive methods during the study period and within 3 months after the last dose of study drug.

Exclusion Criteria:

1. The subject is participating in other interventional clinical studies;
2. The subject has previous or concurrent other malignancies;
3. Lymphoma bone marrow invasion;
4. The presence of symptomatic brain metastases requiring immediate radiotherapy or steroid therapy;
5. Known hypersensitivity to the applied drugs or any excipients；
6. Previous hematopoietic stem cell or bone marrow transplantation；
7. Active infection requiring systemic treatment;
8. Patients with uncontrolled cardiac clinical symptoms or diseases;
9. The subject has severe active infection or unexplained fever > 38.5 degrees during screening or before the first dose (the subject can be enrolled due to tumor fever as judged by the investigator);
10. Radiotherapy or radiotherapy at any site within 2 weeks before study medication;
11. Any investigational drug within 4 weeks before study medication;
12. Live attenuated vaccine within 4 weeks before study medication or possibly during the study period, influenza vaccine can be administered during the influenza season;
13. Pregnant or lactating women;
14. Any reasons that the investigator believes that it should be excluded from this study.