Diagnosis: Metastatic breast cancer

Treatment: Enhertu 100 milligram (mg) vial

The insurer denied coverage for Enhertu 100 mg vial

The denial is overturned

This patient has a history of metastatic breast cancer, with new left pleural effusion. Abraxane was previously used after metastatic progression. Treatment with Enhertu is requested. There is no HER (human epidermal growth factor receptor) marker documented, but the provider indicated that a new indication no longer requires this marker.

Enhertu [5.4mg/ kilogram (kg)] is recently approved in the United States (US) for the treatment of adult patients with unresectable or metastatic HER2-low [Immunohistochemistry (IHC) 1+ or IHC 2+/ in situ hybridization (ISH)-] breast cancer who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within six months of completing adjuvant chemotherapy. For the first time in a clinical trial, DESTINY-Breast04's results showed that patients with low HER2-expressing metastatic breast cancer benefitted from a targeted therapy, trastuzumab deruxtecan (T-DXd/Enhertu), an antibody-drug conjugate (ADC). A note from approximately 2 months ago says that HER is negative. IHC 0 over 5 years but 5 months ago, it was IHC1+(10%).

This patient has a history of metastatic breast cancer, with new left pleural effusion. While the prior denial indicates the medical records provided for review did not show the HER2 marker, the office note from 2 months ago says that HER is negative, IHC1+(10%). HER-2 1+ is considered low HER and this drug is recently approved for this situation when there had been previous chemotherapy.

In this trial involving patients with HER2-low metastatic breast cancer, trastuzumab deruxtecan resulted in significantly longer progression-free and overall survival than the physician's choice of chemotherapy. (Modi et al., 2022)

"Trastuzumab deruxtecan (ENHERTU), a HER2-directed antibody and deoxyribonucleic acid (DNA) topoisomerase I inhibitor conjugate, is being developed for the treatment of HER2-expressing solid tumours, including breast cancer, gastric cancer, colorectal cancer and non-small cell lung. Based primarily on the results of the phase 2 DESTINY-Breast01 trial, trastuzumab deruxtecan was recently approved in the US under accelerated approval for the treatment of adult patients with unresectable or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting. This article summarizes the milestones in the development of trastuzumab deruxtecan leading to this first approval." (Keam, 2020)

"ENHERTU is a HER2-directed antibody and topoisomerase inhibitor conjugate indicated for the treatment of: adult patients with unresectable or metastatic HER2-positive breast cancer who have received a prior anti-HER2-based regimen either:
1.in the metastatic setting, or
2.in the neoadjuvant or adjuvant setting and have developed disease recurrence during or within six months of completing therapy. (1.1)
or adult patients with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma who have received a prior trastuzumab-based regimen." (FDA, 2019)

The health plan did not act reasonably with sound medical judgment in the best interest of the patient.

The insurer's denial of coverage for Enhertu 100 milligram (mg) vial is overturned. Medical Necessity is substantiated.