Korean health agency recognizes HER2 companion diagnostic tests as Level 2 reimbursement target
The Health Insurance Review and Assessment Service (HIRA) has officially determined that the “Level 2” companion diagnosis reimbursement is appropriate for the HER2 (Human Epidermal growth factor Receptor 2) companion diagnostic immunohistochemical (IHC) test, which has been a key concern for pathology departments.
The move will likely pave the way for proper compensation for HER2 tests, which have been criticized for their disproportionately low reimbursement levels compared to PD-L1 (programmed death-ligand 1) and ALK (anaplastic lymphoma kinase).
In response to Roche Diagnostics' application to “confirm whether the IHC test for HER2 companion diagnosis is eligible for reimbursement,” HIRA notified in a letter dated July 4 that the test falls under the Level 2 category of the existing test “I-567 immunohistochemical test.”
However, HIRA stated that it would report to the Ministry of Health and Welfare on the need to establish a new category for HER2 details, indicating that official registration will be made through the ministry’s notification revision later.
Why hasn't the Level 2 reimbursement been applied to HER2 test until now?
The HER2 IHC test is a representative companion diagnostic and is a required test to determine whether to administer Herceptin (trastuzumab).
In Korea, the HER2 test has been widely used in clinical practice even before the introduction of the companion diagnosis reimbursement system. However, even after the introduction of the system, the target was not included in the companion diagnosis fee (Level 2), which prevented patients from receiving benefits.
Even with the same IHC method, companion diagnostics, such as PD-L1 and ALK, have been recognized as Level 2, while the HER2 test has remained at a lower ancillary fee (Level 1), which has been a continuous problem raised by pathology departments.
In particular, since the expression level of HER2 varies by cancer type and diagnostic accuracy is a key criterion for treatment success, pathologists and hospitals have not been compensated commensurately despite the high cost of analysis and quality control.
In response, the Korean Society of Pathologists has repeatedly demanded adequate reimbursement for HER2 IHC tests from health authorities.
The pathologists' position was that HER2 IHC tests require complex interpretation and quality control, and that it was a clear equity issue to exclude them from Level 2 reimbursement even though they fulfill the purpose of companion diagnostics.
In April, Roche Diagnostics requested that HIRA officially confirm the eligibility of the HER2 IHC test for reimbursement. The reagents used in the test are IHC reagents for HER2 companion diagnostics, which meet global guidelines and Korean and international approvals.
As a result of the application, the review panel confirmed that the test falls within the Level 2 range of the existing numerical code. Therefore, it is eligible for medical benefits.
HIRA’s decision is significant because it officially recognizes the technical characteristics and clinical role of the HER2 IHC test within the current reimbursement system. However, for smooth clinical application in practice, it is necessary to incorporate detailed items through revisions to the Health and Welfare Ministry's administrative notification.
As a result, HIRA will likely report the decision to the ministry, and the system will be reorganized to include HER2.
If the ministry's notification is revised to include HER2 in the existing Level 2 category, it will not only ensure that pathologists are adequately compensated for their diagnostic activities but also have a positive impact on the introduction of new drugs and patient access.
Decision will affect diagnostic reimbusement for newer drugs like Enhertu and zanidatamab
Notably, Enhertu (trastuzumab deruxtecan) is a drug administered not only to HER2-positive patients but also to those with low- and ultralow-expression levels of HER2, requiring pathology departments to screen patients across different expression categories through sophisticated IHC interpretation.
However, it has been consistently pointed out that the current low “companion diagnostic reimbursement” (Level 1) is insufficiently reimbursed for the time, manpower, and equipment required to perform such sophisticated diagnostics, which is a barrier to clinical adoption.
Therefore, the inclusion of HER2 as a Level 2 item is expected to increase the utilization of Enhertu and boost its clinical application in Korea.
In addition, since the first HER2-targeting bispecific antibody “zanidatamab,” which is currently under license review by the Ministry of Food and Drug Safety (MFDS), requires patient screening through HER2 testing when introduced in Korea, the recognition of companion diagnostics could contribute to the rapid market entry and establishment of such therapies.
The ball has been passed to the Ministry of Health and Welfare. Relevant medical societies and industry are watching to see if HER2 will be added to the Level 2 list through a revision of the notification.