PFS is defined as the duration from the date of randomization to the date of disease progression determined per Lugano 2014 criteria as assessed by an independent review committee (IRC), or death, whichever occurs first.

CR30 will be determined by positron emission tomography-computerized tomography (cat scan) \[PET-CT\] per Lugano 2014 criteria, as assessed by independent review committee (IRC).

PFS is defined as the time from randomization until disease progression determined by Lugano 2014 criteria per IRC, or death, whichever occurs first.

BOR is defined as Complete Response (CR) or Partial Response (PR), determined by Lugano criteria, as assessed by an IRC.

PFS is defined as duration from the date of randomization to the date of disease progression determined by Lugano criteria by independent review committee (IRC) or death (whichever occurs first).

The number of participants experiencing Cytokine Release Syndrome (CRS) toxicity associated with Epcoritamab therapy will be reported, including Grades 2, 3 and 4. CRS-related toxicity will be assessed according to American Society for Transplantation and Cellular Therapy (ASTCT) criteria.

The number of participants experiencing Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS)-related toxicity including Grades 2, 3 and 4. ICANS-related toxicity will be assessed according to American Society for Transplantation and Cellular Therapy (ASTCT) criteria.

The number of participants experiencing neurologic toxicities associated with Epcoritamab therapy will be reported, including Grades 2, 3 and 4. Neurologic toxicities will be assessed using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, per physician discretion.

The number of participants experiencing fluid accumulation associated with Loncastuximab therapy will be reported, including Grades 2, 3 and 4. Fluid accumulation toxicities will be assessed using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, per physician discretion.

The number of participants experiencing hepatotoxicity (liver-related toxicity) associated with Loncastuximab therapy including Grades 2, 3 and 4 toxicity. Hepatotoxicity will be assessed using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, per physician discretion.

The proportion of participants achieving a best overall response of complete response (CR) after Cycle 12 of study therapy will be reported. Response will be assessed using modified Cheson criteria, if disease is not fluorodeoxyglucose (FDG)-avid in initial Screening; or by revised Lugano criteria if Screening FDG-positron emission tomography (PET)/ computed tomography (CT) demonstrated FDG avid disease. For Lugano criteria, CR will be defined by a Deauville score of ≤3.

uMRD CR as defined by negative leukemia cells to the 10\^6 after 12 cycles of consolidative therapy with epcoritamab measured by Adaptive's NGS MRD assay (ClonoSEQ) in patients who have attained a partial response or better with detectable disease after acalabrutinib or zanubrutinib +/- obinutuzumab treatment for a minimum of 12 cycles of therapy

The overall response rate (ORR) was defined as the proportion of participants achieving complete response (CR) or partial response (PR) based on modified IWWM6 criteria.

CMR will be assessed by PET-CT using the Deauville 5-point scale and Lugano 2014 criteria. Patients who die from any cause or relapse/progress prior to this time-point will be considered non-responders. Patients who don't have a PET-CT scan within the protocol defined window or withdraw from the trial prior to this time-point will be considered non outcome evaluable. Patients who undergo stem-cell transplant (SCT) within 24 weeks of randomisation, patients who fail to start treatment and patients whose ineligibility is deemed to impact upon response to treatment will be replaced and hence not included in the analysis of this outcome

EOT CMR rate defined as the proportion of participants achieving CR per PET/CT Lugano 2014 criteria (protocol appendix B) at the EOT assessment: PET-CT, score 1, 2, or 3 with or without a residual mass on a 5-point scale (5PS) among all patients and separately in Cohorts A and B.

Cytokine Release Syndrome events will be graded using American Society for Transplantation and Cellular Therapy (ASTCT), with a higher grade indicating higher severity.

ICANS events will be graded using ASTCT, with a higher grade indicating higher severity.

Ntox is defined as the percentage of participants who developed at least 1 Grade 3 or higher Ntox since the initiation of epcoritamab treatment.

DLT events are defined as clinically significant adverse events or abnormal laboratory values assessed as unrelated to disease progression, underlying disease, intercurrent illness, or concomitant medications.

Will be assessed using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and American Society for Transplantation and Cellular Therapy (ASTCT) grading for cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The dose limiting toxicity period will be the first 28 days after the first dose of epcoritamab.

AEs will be tabulated by type and grade using the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0 and displayed in summary form. The maximum grade for each type of toxicity will be recorded for each patient, and frequency tables will be reviewed to determine toxicity patterns.

CRS severity will be graded using American Society for Transplantation and Cellular Therapy Cytokine Release Syndrome criteria. The CRS rate will be calculated together with 95% one-sided confidence intervals among evaluable patients.

Kaplan-Meier estimates will be provided. 95% confidence intervals will be generated.

An AE is defined as any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment.

Maximum observed concentration.

AUC from time 0 to time of last measurable concentration within the dosing interval.

Best overall response (BOR) is defined as the percentage of participants in Cohort 1 Part 2 third line plus (3L) R/R DLBCL who achieved best overall response of complete response (CR) or partial response (PR) by Lugano 2014 criteria as assessed by independent review committee (IRC).

DLT events are defined as clinically significant adverse events or abnormal laboratory values assessed as unrelated to disease progression, underlying disease, intercurrent illness, or concomitant medications.

DLT events were defined as clinically significant adverse events (AEs) or abnormal laboratory values assessed as unrelated to disease progression, underlying disease, intercurrent illness, or concomitant medications as assessed per Common Terminology Criteria for Adverse Events (NCI-CTCAE) criteria version 5.0.

CRS and ICANS will be graded based on American Society for Transplantation and Cellular Therapy (ASTCT) criteria. CTLS will be graded according to Cairo-Bishop criteria.

R/R CLL participants will be assessed according to International Workshop on Chronic Lymphocytic Leukemia (iwCLL) criteria and the RS participants according to Lugano criteria. ORR based on the Lugano criteria is defined as the percentage of participants who achieve a response of PR or complete remission (CR), prior to initiation of subsequent therapy. The ORR based on the iwCLL criteria is defined as the percentage of participants who achieve a response of PR, CR with incomplete bone marrow recovery (CRi), or CR, prior to the initiation of subsequent therapy.

DLT events are defined as clinically significant adverse events (AEs) or abnormal laboratory values assessed as unrelated to disease progression, underlying disease, intercurrent illness, or concomitant medications as assessed per Common Terminology Criteria for Adverse Events (NCI-CTCAE) criteria version 5.0.

An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign. (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product.

ORR is defined as the percentage of participants achieving complete response (CR) or partial response (PR) based on Lugano criteria.

To determine the MTD and/or RP2D to be studied in the Expansion part. DLT will be graded according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0.

An AE is any untoward medical occurrence in a clinical trial participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product.

ORR is defined as the percentage of participants achieving complete response (CR) or partial response (PR) based on Lugano criteria.

CRS will be graded based on American Society for Transplantation and Cellular Therapy (ASTCT) criteria.