The Efficacy and Safety of Glofitamab in Combination With PD-1 Antibody and Lenalidomide in Patients With Relapsed/Refractory Large B-cell Lymphoma (LBCL) With TP53 Aberrations: A Prospective, Multicenter, Phase II Clinical Study

This is a Phase II, open-label, single-arm, multicenter study designed to evaluate the safety and efficacy of the Glofitamab-PD-1 inhibitor-Lenalidomide combination therapy (Glofit-PD-1-Len) in patients with TP53-aberrant relapsed or refractory large B-cell lymphoma (R/R LBCL). The study aims to investigate whether this novel therapeutic combination can effectively address the high unmet medical need in this patient population, characterized by poor prognosis and resistance to standard treatments.

The study employs a Simon two-stage design, enrolling a total of 24 participants. In Stage I, an initial cohort of 9 patients will be treated and evaluated. If fewer than 2 patients achieve complete response (CR) per 2014 Lugano criteria (as verified by FDG-PET imaging), the study will be terminated early. If the threshold is met, an additional 15 patients will be recruited in Stage II for further evaluation, bringing the total to 24 patients. The primary endpoint is the best complete response rate (BCR) achieved during the treatment cycle. Secondary endpoints include overall response rate (ORR), progression-free survival (PFS), overall survival (OS), duration of response (DoR), duration of complete remission (DoCR), transplantation rate, and minimal residual disease (MRD)-negative rate at the end of treatment.

The treatment process consists of an induction stage following a screening period of up to 28 days. On Day 1 of the first treatment cycle, patients will receive pretreatment with Obinutuzumab, followed by Glofitamab with stepwise dose escalation, combined with the PD-1 inhibitor and Lenalidomide. Efficacy assessments will occur at predefined time points using Lugano response criteria. The safety of the Glofit-PD-1-Len regimen will be closely monitored, and adverse events will be recorded and graded per CTCAE version 5.0.

Patients will be excluded if they meet criteria such as prior organ transplant, recent exposure to other investigational treatments, or significant comorbid conditions, including active infections and uncontrolled autoimmune diseases. Concomitant therapies, such as corticosteroids (except for specific indications), experimental therapies, and live vaccines, are prohibited. Prophylactic measures for tumor lysis syndrome (TLS), nausea, vomiting, and diarrhea, as well as granulocyte colony-stimulating factor (G-CSF) support, will be implemented as per institutional guidelines.

The risk-benefit profile of this combination is supported by prior studies demonstrating the efficacy and acceptable safety of Glofitamab in combination therapies for LBCL. Given the significant treatment gap for TP53-aberrant R/R LBCL patients, this research seeks to advance outcomes through an innovative therapeutic approach.

Inclusion criteria

• Signed informed consent form before any study-specific procedures.
• Age ≥ 18 years at the time of consent.
• Histologically confirmed large B-cell lymphoma (LBCL) with CD20 expression, including but not limited to:Diffuse large B-cell lymphoma not otherwise specified (DLBCL-NOS),Transformed follicular lymphoma (tFL),Grade 3B follicular lymphoma (3B FL),High-grade B-cell lymphoma (HGBCL),Intravascular large B-cell lymphoma (IVLBCL),Primary mediastinal large B-cell lymphoma (PMBCL),Epstein-Barr virus-positive LBCL (EBV+ LBCL).
• Relapsed or refractory (R/R) LBCL defined as:

Relapsed: Disease recurrence after achieving remission for longer than 6 months after completing the last line of therapy.

Refractory: Failure to achieve remission or progression within 6 months after completing the last line of therapy.

• Confirmed TP53 deletion or mutation via FISH or NGS.
• Not eligible for autologous stem cell transplantation (ASCT) per any of the following criteria: Age ≥ 70 years, End-stage organ dysfunction, ECOG performance status of ≥ 2,Patient decision to decline ASCT, Other investigator-determined comorbidities (e.g., severe heart or lung disease, active infections) per local clinical practice standards.
• Measurable disease at baseline, with at least:

One lymph node lesion ≥ 1.5 cm (in the longest diameter), or One extranodal lesion ≥ 1.0 cm (in the longest diameter).

• ECOG performance status of 0, 1, or 2.
• Life expectancy of ≥ 12 weeks, as assessed by the investigator.
• Adequate hematologic function unless due to extensive bone marrow involvement or spleen-related complications caused by lymphoma, defined as:

Absolute neutrophil count (ANC) ≥ 1.0 × 10⁹/L,Platelets ≥ 50 × 10⁹/L,Hemoglobin ≥ 80 g/L.

-Willingness to adhere to the study procedures, including contraception requirements during the trial for participants of reproductive potential.

Exclusion criteria

• Prior allogeneic stem cell transplantation or organ transplantation. Active central nervous system involvement by lymphoma. Active autoimmune diseases requiring immune suppressive therapy. Uncontrolled systemic infections, including active hepatitis B, hepatitis C, or HIV infection.

Previous treatment with Glofitamab, another bispecific antibody targeting CD20 and CD3, or PD-1 inhibitors combined with Lenalidomide.

History of severe hypersensitivity to monoclonal antibodies or any components of the study drugs.

Concurrent participation in another investigational study. Use of systemic immunosuppressive therapy within 14 days prior to enrollment (excluding corticosteroids for lymphoma treatment or prevention of adverse effects).

Pregnant or breastfeeding women. Any psychological, social, or medical condition that, in the investigator's opinion, could interfere with study compliance or compromise the participants' safety or outcome.