Background: The Oncology Care Model (OCM) is a Medicare value-based care program, that rewards practices for decreasing the total cost of care (TCOC) compared to a benchmark price. Enrolled patients are evaluated in 6-month episodes within a 1-year time window called Performance Periods (PP). The use of lower cost medication alternatives (LCA) is a critical strategy to bend the cost curve. Therapeutic interchange (TIC) with lower-cost generic/biosimilar/therapeutic alternative medications offer significant cost savings to payers and patients while maintaining equivalent quality of care. LCA for eight high-cost oncology therapeutic or supportive care medications became available during or just prior to OCM. The results of a clinically appropriate, physician-supported, pharmacist-led interchange of high-cost medications to LCA in The US Oncology Network (The Network) during OCM PP 7 (PP7), 8 (PP8), and 9 (PP9) is described here. Methods: Medicare Part B & D claims for 14 OCM practices in The Network were used to evaluate the impact of eight TIC opportunities during PP 7-9. TIC opportunities included changing therapy from reference products to biosimilars (bevacizumab, trastuzumab, rituximab, pegfilgrastim and filgrastim), from brand to generics (abiraterone, imatinib, fosaprepitant) and from high cost to LCA (aprepitant to fosaprepitant, denosumab to zoledronic acid). TCOC impact was measured by comparing the cost of each dose of the LCA vs the estimated cost if the more expensive alternative had been used instead. Results: The shift from high cost to LCAs in PP7, PP8 and PP9 is shown in Table as percentage of total doses dispensed or administered. Transitions from aprepitant to fosaprepitant, and from denosumab to zoledronic acid was done when clinically appropriate (as determined by the treating physician). The cumulative savings from TIC was $26.0M in PP7, $32.3M in PP8 and $32.9M in PP9. TIC to biosimilars contributed $6.6M in PP8 and $12.2M in PP9 of the cumulative savings. TIC reduced TCOC by 2.78% in PP7, 4.13% in PP8, 5.25% in PP9 within the OCM. Conclusions: TIC to biosimilars, generics and clinically appropriate LCA is an effective way to reduce TCOC while maintaining quality care in the OCM. Even small shifts in utilization towards LCA can generate a significant reduction in TCOC. Physician-supported, pharmacist-led TIC initiatives are critical to bending the cost curve within Oncology.