Abstract P4-01-40: Real World Data with Off-Label Insurance Approval of Trastuzumab Deruxtecan in Metastatic Breast Cancer
Authors: Bobolts Laura R. , Mangurian Mark , Marur Shanthi , Wise Corey , Pozotrigo Melissa , Solomon Hiywete , Hartung Nicole , Ravindranathan Meera , Makielski Rory , Marur Shika , Toler Andrew 
Published: March 2023

Abstract
Background: Trastuzumab deruxtecan (T-DXd) improves outcomes in HER2-positive, and recently in HER2-low (IHC 1+ or IHC 2+/ISH-) previously treated metastatic breast cancer (MBC) patients. OncoHealth is a digital health care company that leverages managed care-trained, board-certified oncologists and oncology pharmacists to review the appropriateness of prior authorization (PA) requests for cancer treatment regimens. Our objective was to examine the rate of off-label PA approvals for T-DXd in MBC.
Methods: We performed a retrospective cross-sectional study of T-DXd PA approvals by OncoHealth for MBC patients between 1/17/2020 – 6/21/2022. Using medical records and utilization management data, we assessed the prevalence of PA approvals for T-DXd in HER2-low and HER2-positive MBC patients according to PA support at the time of approval, whether on-label, off-label NCCN compendium supported, off-label acceptable scientific literature-only (LIT) supported, or approved by clinical justification if off-label/off-NCCN or LIT.
Results: We identified 156 patients with MBC with a PA approval for T-DXd. The median patient age range was 60-69 years, 85% had visceral disease, 28% had brain metastases, 93.6% had HER2-positive MBC and remaining were HER2-low MBC. The median line of T-DXd therapy was 6 (range, 1-15) for HER2-low and 3 (range, 1-10) for HER2-positive MBC. All HER2-low T-DXd cases were supported by LIT and approved prior to NCCN guidelines incorporation in 6/21/2022. Among HER2-positive MBC patients, 25% (37/146) of PA approvals were off-label. Of these, 57% (21/37) were supported by NCCN, and the remaining 43% (16/37) were approved off-label/off-NCCN or LIT. The majority of the off-label/off-NCCN or LIT cases (10/16) were approved by clinical judgement based on 2nd line HER2-positive MBC abstract data from DESTINY-Breast03 presented at ESMO on 9/19/21.
Conclusions: All off-label PA approvals for T-DXd in HER2-low MBC occurred prior to NCCN’s incorporation, expanding access. One quarter of all T-DXd approvals in HER2-positive MBC were off-label. Leveraging managed care, board-certified oncology clinicians with knowledge of the latest cancer therapies and use of additional coverage determination resources such as NCCN and acceptable scientific literature can help expedite and expand access to off-label anti-cancer drugs that may be beneficial for cancer patients.
Table 1: T-DXd Authorization Approvals
Citation Format: Laura R. Bobolts, Mark Mangurian, Shanthi Marur, Corey Wise, Melissa Pozotrigo, Hiywete Solomon, Nicole Hartung, Meera Ravindranathan, Rory Makielski, Shika Marur, Andrew Toler. Real World Data with Off-Label Insurance Approval of Trastuzumab Deruxtecan in Metastatic Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-40.