This is a prospective, observational, non-interventional real-world study that will not alter participants' routine clinical care. Approximately 20 eligible patients with diffuse large B-cell lymphoma (DLBCL) will be enrolled. Treatment decisions will be made by the treating physician based on standard clinical practice and may include glofitamab monotherapy or glofitamab-based combination regimens, such as glofitamab plus gemcitabine and oxaliplatin (Glofit-GemOx) or glofitamab plus polatuzumab-based therapy (Glofit-Pola).

The study will collect baseline characteristics (including age, sex, medical history, and molecular subtype), treatment information, laboratory test results, adverse events, and survival follow-up data. Circulating tumor DNA (ctDNA) testing will be performed to assess minimal residual disease (MRD) in peripheral blood. When clinically indicated, cerebrospinal fluid samples may be collected to measure drug concentration.

All personal information will be kept strictly confidential. Identifiable information will be removed and replaced with coded study numbers. Medical records will be maintained at the study site and accessed only by authorized research personnel. Representatives from the sponsor, ethics committee, or regulatory authorities may review study records as required. Study results will be published in aggregated form without including any information that could identify individual participants. Study data and personal information will be used solely for research purposes.

Inclusion Criteria:

• Participants must meet all of the following criteria:

  1. Age ≥18 years at the time of treatment initiation.

  2. Histologically or pathologically confirmed diffuse large B-cell lymphoma (DLBCL).

  3. Patients with primary refractory disease or early relapse, defined as:

     Failure to achieve complete response (CR) after at least 4 cycles of first-line induction therapy, or

     Relapse confirmed by imaging within 12 months after achieving CR following first-line therapy.

  4. Patients who plan to initiate a glofitamab-containing treatment regimen (either monotherapy or combination therapy) within 12 months after study initiation.

  5. Willing and able to comply with study follow-up and data collection requirements.

Exclusion Criteria:

• Participants meeting any of the following criteria will be excluded:

  1. Currently participating in, or planning to participate in, any interventional clinical trial.
  2. Any condition that, in the investigator's judgment, would make the patient unsuitable for participation in this study (e.g., inability to complete follow-up, safety concerns, or significant comorbidities).

The study population will include adult patients (≥18 years) with histologically confirmed diffuse large B-cell lymphoma (DLBCL) who have primary refractory disease or early relapse after first-line therapy. Eligible patients are those who plan to initiate a glofitamab-containing treatment regimen (either as monotherapy or in combination with other agents) in routine clinical practice. Patients will be enrolled from participating centers and followed prospectively to evaluate treatment outcomes and safety in a real-world setting.