• Men and women ≥18 years of age and ≤60 years of age on the day of signing the informed consent form (or the legal age of consent in the jurisdiction in which the study is taking place).

• Patients must have histologic confirmation of classical Hodgkin Lymphoma (cHL) defined by the World Health Organization (WHO) classification.

• Baseline Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) Computed Tomography (CT) must demonstrate Fluorodeoxyglucose (FDG) avid lesions compatible with computed tomography (CT)-defined anatomical tumor sites. Patients should have at least 1 measurable site of disease per Lugano classification in Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG-PET/CT) or CT scans.

• Patients must have a clinical stage consistent with:

• a. Stage 2 B cHL with one or both of the following risk factors: i. Large mediastinal mass (≥1/3 of the maximum transverse thoracic diameter) ii. Extranodal disease b. Stage III or Stage IV cHL based on Lugano criteria based on FDG-PET/CT.

• Eastern Cooperative Oncology Group (ECOG) performance score (PS)≤ 2, except due to lymphoma involvement.

• Life expectancy ≥3 months.

• Women should avoid becoming pregnant for the full duration of chemotherapy and for up to 6 months after ending treatment. Therefore, women of childbearing potential must use highly effective contraceptive measures during treatment and for up to 6 months after stopping treatment. It is currently unknown whether brentuximab vedotin may reduce the effectiveness of hormonal contraceptives, and therefore, women using hormonal contraceptives should add a barrier method. Pregnancy testing is recommended for women of reproductive potential prior to initiating therapy.

• Agreement to use contraception during study participation.

‣ Female patients of childbearing potential must use highly effective methods of contraception.

‣ Patients using hormonal contraceptives (eg, birth control pills or devices) must use a barrier method of contraception (eg, condoms) as well.

‣ A woman is considered of childbearing potential, ie, fertile, following menarche and until becoming postmenopausal, unless permanently sterile. Permanent sterilization methods include hysterectomy, bilateral salpingectomy, and bilateral oophorectomy.

‣ A post-menopausal state is defined as no menses for 12 months without an alternative medical cause.

• Male patients with a female partner of childbearing potential are eligible if they abstain from sexual intercourse, are vasectomized, or if they agree to the use of barrier contraception with other methods described above during the study treatment period and for 120 days after the last dose of brentuximab vedotin.

• Patients must have normal organ and marrow function as defined below:

∙ Absolute neutrophil count (ANC) \>1,000 cells/mm3 independent of growth factor support within 7 days of study entry (≥750 cells/mm3 if lymphoma involvement of the bone marrow or spleen).

‣ Platelets ≥75,000 platelets/mm3 independent of transfusion support within 7 days of study entry (≥50,000 platelets/mm3 independent of transfusion support within 7 days of study entry if lymphoma involvement of the bone marrow or spleen).

‣ Hemoglobin \>9 g/dL or \>8 g/dL in case of bone marrow involvement by lymphoma independent of transfusion support within 7 days of study entry.

‣ Serum total bilirubin ≤2x upper limit of normal (ULN; except patients with Gilberts syndrome).

‣ Aspartate aminotransferase (AST; serum glutamic-oxaloacetic transaminase) and alanine transaminase (ALT; serum glutamic-pyruvic transaminase) ≤2.5x institutional ULN (≤3x institutional ULN if lymphoma involvement of the liver).

‣ Creatinine within normal institutional limits or creatinine clearance ≥40 mL/min (as estimated by the Cockcroft-Gault equation or alternative formula according to institutional guidelines) for patients with creatinine levels above institutional normal.

⁃ Able to provide written informed consent and can understand and agree to comply with the requirements of the study and the schedule of assessments (SoA).