Biosimilar Use Among 38 ASCO PracticeNET Practices, 2019-2021.

PURPOSE: Biosimilars offer increased patient choice and potential cost-savings, compared with originator biologics. We studied 3 years of prescribed biologics among US physician practices to determine the relationship of practice type and payment source to oncology biosimilar use. METHODS: We acquired biologic utilization data from 38 practices participating in PracticeNET. We focused on six biologics (bevacizumab, epoetin alfa, filgrastim, pegfilgrastim, rituximab, and trastuzumab) for the period from 2019 to 2021. We complemented our quantitative analysis with a survey of PracticeNET participants (prescribers and practice leaders) to reveal potential motivators and barriers to biosimilar use. We implemented logistic regression to evaluate the biosimilar use for each biologic, with covariates including time, practice type, and payment source, and accounted for clusters of practices. RESULTS: Use of biosimilars increased over the 3-year period, reaching between 51% and 80% of administered doses by the fourth quarter of 2021, depending on the biologic. Biosimilar use varied by practice, with independent physician practices having higher use of biosimilars for epoetin alfa, filgrastim, rituximab, and trastuzumab. Compared with commercial health plans, Medicaid plans had lower biosimilar use for four biologics; traditional Medicare had lower use for five biologics. The average cost per dose decreased between 24% and 41%, dependent on the biologic. CONCLUSION: Biosimilars have, through increased use, lowered the average cost per dose of the studied biologics. Biosimilar use differed by originator biologic, practice type, and payment source. There remains further opportunity for increases in biosimilar use among certain practices and payers.

On-Board Imager-based MammoSite treatment verification.

Contemporary radiation oncology departments are often lacking a conventional simulator due to common use of virtual simulation and recent implementation of image guided radiation therapy. A protocol based on MammoSite method was developed using CT based planning, a Source Position Simulator (SPS) with a Simulator Wire and a linear accelerator based On-Board Imager (OBI) for daily verification. After MammoSite balloon implantation, the patient undergoes a CT study. The images are evaluated for tissue conformance, balloon symmetry, and balloon surface to skin distance according to the departmental procedure. Prior to the CT study the SPS is attached to the transfer tube that in turn is attached to the balloon catheter. The length from the indexer to the first dwell position is measured using the simulator wire with X-ray markers. After the CT study is performed, the data set is sent to the Varian Eclipse treatment planning system (TPS) and to the Nucletron PLATO brachytherapy planning system. The reference digitally reconstructed radiographs (DRRs) of anterior and lateral setup fields are created using Eclipse TPS and are immediately available on the OBI console via the Varian Vision integrated system. The source dwell position coinciding with the balloon center is identified in the CT dataset, followed by the offset calculation, catheter reconstruction, dose points placement and dwell time calculation. OBI fluoroscopy images are acquired and marked as initial. Prior to each treatment fraction balloon diameter and symmetry are evaluated using OBI fluoroscopy and tools available on the OBI console. Acquired images are compared with reference DRRs and/or initial OBI images. The whole process from initial evaluation to daily verification is filmless and does not undermine the precision of the procedure. This verification time does not exceed 10 min. The balloon diameter correlates well (within 1 mm) between initial CT and OBI verification images. The balloon symmetry is defined with 1 mm accuracy using existing OBI console tools. It is feasible to use OBI based simulation for the MammoSite balloon placement evaluation, balloon integrity daily verification, and treatment dwell position coincidence with balloon center. This verification is a rapid process and is an alternative to the conventional simulator based technique. The simulator wire with X-ray markers for the SPS is the recommended tool for the CT based MammoSite procedure.