This comparative effectiveness and descriptive retrospective cohort study will evaluate safety and effectiveness outcomes among commercially insured adults who received a granulocyte colony stimulating factor (G-CSF) biosimilar or originator product during the first cycle of clinical guideline-indicated intermediate or high febrile neutropenia risk chemotherapy.

This comparative effectiveness and descriptive retrospective cohort study includes commercially insured adults enrolled in one of four health plans participating in the Biologics and Biosimilars Collective Intelligence Consortium (BBCIC) Distributed Research Network. The investigators included patients who received a granulocyte colony stimulating factor (G-CSF) biosimilar or originator product during the first cycle of clinical guideline-indicated intermediate or high febrile neutropenia risk chemotherapy. The investigators will collect patient demographics, cancer diagnosis, chemotherapy regimen, and patterns of G-CSF biosimilar and originator product use. The investigators will follow patients from first G-CSF exposure until up to six cycles of chemotherapy receipt, death, or insurance disenrollment. The primary effectiveness outcome is incidence of febrile neutropenia. Secondary outcomes include incidence of adverse events and trends in product use over time. The investigators will compare febrile neutropenia incidence between originator and biosimilar products using inverse probability weighting to control for confounding. Secondary analyses will examine 'as treated' outcomes.

Inclusion Criteria:

• Patients age 20 or older
• Diagnosis of lung, breast, colon, ovarian, pancreatic, testicular, cervical, uterine, or NHL cancer
• Beginning intermediate or high neutropenia risk chemotherapy

Exclusion Criteria:

• One inpatient or two outpatient cancer diagnoses at least 30 days apart in the 183 days prior to the Index Date for cancer different from enrolling cancer diagnosis
• Any of the following in 183 days prior to Index Date:
• Any chemotherapy or G-CSF product receipt
• 2< medical claims at least 30 days apart for a skilled nursing facility or hospice care
• 2< diagnoses/procedure codes at least 1 day apart for cancer-related radiotherapy, bone marrow or stem cell transplant, diagnosis of HIV/AIDS, severe hepatic disease, chronic kidney disease, or any non-oncology related neutropenia

Patients with lung, breast, colon, ovarian, pancreatic, testicular, cervical, uterine, or NHL cancers initiating clinical guideline-indicated intermediate or high neutropenia risk chemotherapy between March 1, 2015 and December 31, 2019. Study period observation ends by June 30, 2020 for participant follow-up. A 12-month look-back prior to the study period (i.e. as early as March 1, 2014) will be used to ensure health plan enrollment, find incident cancer diagnoses, and provide a description of reference G-CSF utilization before biosimilar introduction to the US market.