(032) Real-World Utilization Patterns of Immune Checkpoint Inhibitors: based on the National Health Insurance Service Data in Korea (2017-2022)

Background: Recent expansions in the indications for immune checkpoint inhibitors (ICIs) and the reported benefits of their combination with traditional anticancer therapies, are expected to boost their utilization. However, previous studies on the use of ICIs have been limited to a few drugs. This study aims to comprehensively understand the utilization of all types of ICIs.

Objectives: To identify patterns of use of immune checkpoint inhibitors in combination with other anticancer therapies, including use by indication and year using claims data from the National Health Insurance Service in Korea.

Methods: In a cross-sectional study, we investigated utilization of ICIs using databases from the National Health Insurance Service (NHIS, 2017-2022) in Korea. Patients with cancer included in the study were those who received at least one dose of atezolizumab (ATC-code: L01FF05), avelumab(L01FF04), durvalumab(L01FF03), ipilimumab(L01FX04), nivolumab(L01FF01), or pembrolizumab (L01FF02) between Jan 2017 and Dec 2022, as defined by drug codes in claims data. Cancers were identified using ICD-10 codes and included skin cancer (C43-44), lung cancer (C34), mesothelioma of pleura (C45.0), urinary tract cancer (C64-C68), colorectal cancer (C18-C20), breast cancer (C50), cervical cancer (C53), liver/biliary tract cancer (C22-C24), head and neck cancer (C00-C14, C30-C32), Hodgkin lymphoma (C81), and endometrial cancer (C54).

Results: A total of 41,216 patients received at least one ICIs from 2017 to 2022. Among patients who started ICIs, 72.1% (n=29,701) used ICIs monotherapy and 27.9% (n=11,515) used ICIs in combination with other anticancer therapies. Among ICIs used as monotherapy, the most frequently drugs were atezolizumab (35.2%), pembrolizumab (32.7%), nivolumab (22.2%), and ipilimumab+nivolumab (3.1%). When ICIs were combined with other anticancer therapies, the most frequent drugs were atezolizumab (59.1%) and pembrolizumab (38.1%), mostly combined with chemotherapy. Between 2017 and 2022, the number of patients using ICIs increased from 1,157 to 15,036, with an increase every year. There was an increase in concurrent use of ICIs from 297 to 618 between 2021 and 2022. Among ICIs used as monotherapy, the use of pembrolizumab increased sharply in 2022. The use of ICIs in combination with other anticancer therapies has risen since 2020. The most common indications associated with use of ICIs are lung cancer (66.6%), urinary tract cancer (11.3%), and liver/biliary tract cancer (10.6%).

Conclusions: Between 2017 and 2022, 41,216 patients received ICIs in Korea, with the number of patients using them increasing every year. In addition, concurrent use of ICIs has increased in recent years.