LME-Guided Precision Combination Therapy in B-cell Lymphoma Patients After CD19 CAR-T Failure

An Exploratory, Two-Arm Study of LME Subtype-Guided Precision Combination Therapy Strategies in Patients With B-Cell Lymphoma After CD19 CAR-T Therapy Failure

This study evaluates a personalized treatment strategy for patients with large B-cell lymphoma (LBCL) whose disease has relapsed or not responded after CD19 CAR-T cell therapy. Researchers believe that the area surrounding the tumor, called the lymphoma microenvironment (LME), plays a major role in why treatments fail.

In this study, researchers will classify patients into four different LME subtypes (GC, IN, ME, or DE) using a standard lab test on their tumor samples. Patients will then be randomly assigned to one of two groups. The control group will receive a standard single-drug therapy (glofitamab). The experimental group will receive a tailored combination therapy based specifically on their tumor's LME subtype. The main hypothesis of this study is that customizing the treatment based on the tumor's microenvironment will significantly improve how long patients live without their disease getting worse (progression-free survival) compared to the standard single-drug approach.

Chimeric antigen receptor T-cell (CAR-T) therapy targeting CD19 has significantly improved outcomes for patients with relapsed or refractory large B-cell lymphoma (R/R LBCL). However, a substantial number of patients still experience treatment failure, and their prognosis is historically very poor, with limited standard treatment options available. Recent scientific evidence suggests that the tumor microenvironment-a complex ecosystem of immune cells, structural cells, and signals surrounding the lymphoma-acts as a critical barrier that drives resistance to CAR-T and other immunotherapies.

This prospective, open-label, randomized clinical trial introduces a "microenvironment-guided" precision immunotherapy approach. Researchers utilize a practical immunohistochemistry (IHC)-based classification system to categorize the lymphoma microenvironment (LME) of each patient into four distinct subtypes: Germinal Center-like (GC), Interstitial (IN), Mesenchymal (ME), and Depleted (DE). Each subtype corresponds to a specific immune suppression mechanism or survival pathway.

Participants will be randomly assigned in a 1:1 ratio to either an experimental group or a control group.

Control Group: Participants will receive monotherapy with glofitamab, a CD3xCD20 bispecific antibody.

Experimental Group: Participants will receive a tailored combination regimen built upon a glofitamab backbone. The additional therapies are specifically matched to their LME subtype to overcome their unique resistance mechanisms. The regimens include:

GC Type: Glofitamab + a BCL-2 inhibitor IN Type: Glofitamab + a PD-1 inhibitor + Lenalidomide ME Type: Glofitamab + local radiotherapy + a BTK inhibitor DE Type: Glofitamab + Chidamide (an HDAC inhibitor) By systematically matching therapies to the specific vulnerabilities of the patient's tumor microenvironment, this study aims to break CAR-T resistance, achieve deeper remissions, and establish a new biomarker-driven treatment paradigm for this challenging clinical scenario.

Inclusion Criteria:

• Age ≥ 18 years, regardless of gender.
• Histologically confirmed large B-cell lymphoma (LBCL), including diffuse large B-cell lymphoma (DLBCL, not otherwise specified) or high-grade B-cell lymphoma.
• Received prior CD19-targeted chimeric antigen receptor (CAR) T-cell therapy.
• Confirmed stable disease (SD) or progressive disease (PD) at the most recent imaging assessment (according to Lugano 2014 criteria) following CAR-T therapy.
• Able to provide a formalin-fixed paraffin-embedded (FFPE) tumor tissue sample (fresh biopsy or archival specimen obtained before CAR-T therapy or after recent progression) with sufficient quantity and quality for immunohistochemistry (IHC) testing.
• Confirmed CD20-positive tumor cells by central laboratory IHC testing.
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2.
• Adequate organ function (including bone marrow, liver, kidney, and heart).
• Women of childbearing potential must agree to use highly effective contraception during the study and for a specified period after the last dose of study drug; male patients must agree to use effective contraception during the study and for a specified period after the last dose.
• Voluntarily agreed to participate in the study, signed the written informed consent form, and willing to comply with the study visit schedule and other protocol requirements.

Exclusion Criteria:

• Prior treatment with glofitamab resulting in disease progression.
• Known severe allergic reactions to any components of the study drugs.
• Active central nervous system (CNS) lymphoma involvement.
• Presence of a severe, uncontrolled active infection.
• Presence of severe cardiovascular or cerebrovascular diseases, uncontrolled diabetes, or uncontrolled hypertension that, in the investigator's judgment, makes the patient unsuitable for study participation.
• History of or current other malignancies (exceptions: adequately treated basal cell carcinoma of the skin, carcinoma in situ of the cervix, etc.).
• Pregnant or breastfeeding women.
• Positive for human immunodeficiency virus (HIV) antibody, or active hepatitis B virus (HBV) infection (HBsAg positive with HBV-DNA > 1x10^3 copies/mL), or active hepatitis C virus (HCV) infection (HCV antibody positive and HCV-RNA positive).
• Any medical or psychiatric condition that might interfere with study execution or result interpretation, or place the patient at unacceptable risk.
• Received other anti-tumor therapies (including chemotherapy, radiotherapy, immunotherapy, etc.) within 2 weeks prior to study enrollment, or have not recovered from toxicities of prior therapies to ≤ Grade 1 or baseline levels (excluding alopecia or other irreversible but non-clinically significant toxicities).