OBJECTIVES: Multiple oncology biosimilar monoclonal antibodies (mAbs) are now available for use as therapeutic options with comparable safety/efficacy profiles to that of their reference biologics. The objective of this study was to describe real-world treatment pattens of rituximab-pvvr, trastuzumab-qyyp, and bevacizumab-bvzr and their associated reference biologics.

METHODS: Closed claims data from Komodo Health from 11/1/2018-5/1/2021 were used for this study. Patients age ≥18, who were newly initiating therapy with a biosimilar (rituximab-pvvr/trastuzumab-qyyp/bevacizumab-bvzr) or the reference biologics (rituximab/trastuzumab/bevacizumab) between 11/1/2019-11/1/2020 for an indicated oncology diagnosis, who had continuous insurance eligibility 360-days pre-mAb-index through 180-days post-mAb-index, were included. Treatment patterns assessed included time-to-therapy-initiation from index diagnosis (identified during 360-day pre-mAb-index period), concomitant medication-use including drug regimens, and switching patterns.

RESULTS: A total of 585 and 5621 patients initiating therapy with a biosimilar or reference-biologic were included, respectively. The biosimilar-initiator/reference-biologic-initiator cohorts both displayed utilization across all similarly-indicated oncology diagnoses, with the largest diagnosis-cohorts for rituximab-indicated, trastuzumab-indicated, and bevacizumab-indicated conditions being non-Hodgkin’s lymphoma (NHL) [rituximab-pvvr=304(91.0%); rituximab=2151(90.8%)], breast cancer (BC) [trastuzumab-qyyp=105(91.3%); trastuzumab=878(94.5%)], and colorectal cancer (CRC) [bevacizumab-bvzr=86(63.2%); bevacizumab=1333(57.4%)]. Time-to-therapy-initiation was similar for both biosimilar-initiators and reference-biologic-initiators for patients with NHL [(rituximab-pvvr mean days=119; SD=123), (rituximab mean days=123; SD=127)], BC [(trastuzumab-qyyp mean days=91; SD=96), (trastuzumab mean days=97; SD=98)], and CRC [(bevacizumab-bvzr mean days=171; SD=144), (bevacizumab mean days=202; SD=141)]. Both originator and biosimilar products were used along with specific drug regimens for NHL (CHOP, CVP, DHAP), BC (docetaxel+carboplatin+pertuzumab, docetaxel+carboplatin, pertuzumab+paclitaxel/docetaxel), and CRC (FOLFOX, CAPOX, FOLFIRI, FOLFOXIRI). Switching among biologics was also observed; the proportion of patients who utilized a different manufacturer-produced mAb-biologic following initiation with the biosimilar or reference-biologic were: 6.9% and 7.4% for NHL, 17.4% and 21.9% for BC, and 2.3% and 12.2% for CRC, respectively.

CONCLUSIONS: Biosimilar-mAb products are being utilized in a manner similar to their reference biologic-mAbs in real-world clinical settings.