Study on the Safety and Effectiveness of Pembrolizumab with Chemotherapy in Children and Young Adults with Classical Hodgkin Lymphoma

Inclusion Criteria

• Newly diagnosed with classical Hodgkin Lymphoma (cHL) at specific stages: Group 1 (Stages IA, IB, IIA without large tumors) or Group 2 (Stages IIEB, IIIEA, IIIEB, IIIB, IVA, IVB).
• Have measurable disease as determined by the study doctor.
• Male participants must agree to avoid donating sperm and use contraception or abstain from heterosexual intercourse during the study.
• Female participants must not be pregnant or breastfeeding and must agree to use contraception during the study and for 120 days after the last dose.
• Must have a performance status score of at least 50 on the Lansky Play-Performance Scale (for children up to 16) or the Karnofsky score (for those 16 and older).
• Must have adequate organ function.

Exclusion Criteria

• Have had a solid organ transplant or a stem cell transplant in the last 5 years.
• Positive pregnancy test for women of childbearing potential within 24 hours before starting the study.
• Heart function below specific levels.
• Previous treatment with pembrolizumab or similar drugs.
• Have received any cancer treatment or investigational drugs for the current diagnosis before joining the study.
• Have received a live vaccine within 30 days before starting the study.
• Have a different type of Hodgkin Lymphoma (lymphocyte-predominant).
• Have an immune deficiency or are on long-term steroid therapy.
• Have another active cancer or have had one in the last 3 years.
• Have cancer that has spread to the brain or spinal cord.
• Severe allergy to study drugs.
• Have an autoimmune disease needing treatment in the last 2 years.
• Have lung disease requiring steroids or current lung disease.
• Have an active infection needing treatment.
• Have HIV, Hepatitis B, or active Hepatitis C.
• Have any condition that could interfere with the study or is not in the participant's best interest.
• Have psychiatric or substance abuse issues that would interfere with the study.
• Have not recovered from major surgery or have ongoing surgical issues.