A Study to Evaluate the Safety and Pharmacokinetics of Eflapegrastim in Pediatric Participants With Solid Tumors or Lymphomas and Treated With Myelosuppressive Chemotherapy

Prior treatment

• Participant has had previous exposure to filgrastim (within 7 days), pegfilgrastim (within 14 days), or other granulocyte colony stimulating factor (G-CSF) products in clinical development within 2 weeks prior to the administration of study drug (eflapegrastim)
• Participant requires concurrent radiation therapy specifically in Cycle 1.
• Participant has had prior bone marrow or hematopoietic stem cell transplant and/or has concurrent bone marrow involvement in their malignancy, including leukemia.
• Participant has had spinal radiation therapy within 30 days prior to study enrollment.
• Participant has used any investigational drugs, biologics or devices within 30 days prior to study treatment or plans to use any of these during the study.
• Participant has a known sensitivity or previous reactions to any of the G-CSF products.
• Participant has not recovered from previous treatment adverse events to ≤Grade 1.

Other illness

• Participant has an uncontrollable infection, has an underlying medical condition, and/or another serious illness that would impair the ability of the participant to receive protocol-specified treatment.
• Participant with active CNS disease.

• Participant must have a pathologic/histologic confirmed newly diagnosed/relapsed/recurrent solid tumor or lymphoma without bone marrow involvement.
• Participant must be a candidate to receive myelosuppressive chemotherapy, with a febrile neutropenia rate of at least 20% as outlined in the National Comprehensive Cancer Network (NCCN) guidelines.
• Participant has adequate hematological, renal, and hepatic function.
• Participant must have an echocardiogram (ECHO) or multigated acquisition (MUGA) within 14 days of Screening if receiving a cardiotoxic therapy and have a cardiac ejection fraction of \>50%.
• Participant must have a lumbar puncture, if clinically indicated, to rule out central nervous system (CNS) involvement within 14 days of study entry.
• Participant has a Karnofsky performance level ≥50% for patients ≥16 years of age or a Lansky performance level ≥50 for children \<16 years of age.