Background: Tennessee Oncology (TO) is a large, outpatient community oncology practice with over 200 providers and 35 clinical sites of care across Tennessee and northern Georgia. As an Oncology Care Model (OCM) participant, TO received claims data from Medicare during its OCM participation from 2016-2021. TO adopted continuous quality improvement initiatives to succeed in the program. Here we highlight our adoption of biosimilars and implementation of an independent clinical pathway program. Methods: OCM claims data received from Medicare were analyzed to determine total cost of care (TCOC) per the OCM methodology. TCOC subgroup analysis was conducted by percentage of spend over time on therapeutic and supportive care drugs, emergency room utilization, and hospitalizations. Biosimilar adoption and pathway utilization rates were tracked internally. Results: 27,927 OCM episodes were attributed to TO during the study period 2016-2021. During this time frame and as a percentage of TCOC, total drug spending increased from 58% to 71%. Conversely, spending on hospital and emergency room utilization as a percentage of TCOC decreased from 11.6% to 7.9% and 1.4% to 1.0%, respectively. Within drug spending, the ratio of supportive to therapeutic drug costs decreased from 29.5% to 7.5%. Despite increased spend on therapeutic drugs towards the end of the model, pathway adherence was over 90%, and trastuzumab and bevacizumab biosimilar adoption rates were over 86% and 97%, respectively. Conclusions: Relative contributions to TCOC changed over time during OCM. The percentage of costs associated with pharmaceuticals increased, while costs associated with hospitalizations and emergency room utilization decreased. Within costs for pharmaceuticals, there was a significant increase in the percentage of costs for therapeutics versus supportive care drugs. High rates of biosimilar conversion and pathway adherence suggest increased drug spend reflects a change in oncology practice, not an effect of inappropriate utilization. These trends have implications for future developments of oncology value-based care programs.