Real-World Treatment Patterns, Outcomes, Health Care Resource Utilization and Cost Burden of Multiple Myeloma in South Korea Using the National Claims Data
Authors: PARK YoungJu , Park Sung Soo , Yoon Soomin , Jeong Jihyeon , Lee Doik , Kim Kihyun 
Published: December 2023

Introduction
As multiple myeloma (MM) treatments are rapidly evolving, treatment outcomes significantly have improved over the last decade while the disease burden is inevitably rising. Understanding the real-world treatment patterns and health care resource utilization (HCRU) and costs associated with the novel agents is important in evaluating the value of novel treatments. This study aimed to describe the trends of treatment patterns, outcomes, HCRU and cost burden of MM in real-world practice between 2010 and 2020.
Methods
A retrospective observational study was conducted using the national insurance claims database provided by the Heath Insurance Review and Assessment, which covers the entire South Korean population. MM patients newly diagnosed from January 2010 to December 2019 were followed up from their first MM diagnosis to the earliest of death or the end of study period.
An algorithm was developed to identify MM regimens and lines of therapy (LOT); MM drugs prescribed within the first 21 days of LOT initiation were considered to constitute the same LOT, and MM drugs that were not part of the LOT or prescribed after 180 days from the last observed prescription were considered to initiate the next LOT. Time to next treatment (TTNT), treatment duration (TD), and 5-year survival rate were assessed descriptively. Overall survival (OS) was estimated using the Kaplan-Meier method with log-rank test for significance. HCRU and costs were assessed during the TTNT and TD of each LOT. MM-related HCRU and costs included MM and MM-related comorbidities.
Results
Among 11,450 eligible patients, 3,080 (26.9%) patients received stem cell transplant (SCT) and 9,825 (85.8%) patients received the 1st LOT (1L). Of these patients, 5,346 (46.7%) patients advanced to 2L, 2,759 (24.1%) patients to 3L, 1,431 (12.5%) patients to 4L, and 709 (6.2%) patients to 5+L.
In SCT patients, after the novel agent introduction, the most common regimens changed to VT (bortezomib/thalidomide) from T in 1L, KR (carfilzomib/lenalidomide) from V in 2L, P (pomalidomide) from R in 3L, and D (daratumumab) from R in 4L. In non-SCT patients, the most common regimens in 1L (VM) and 2L (R) did not change after the novel agent introduction while P and D became most common from R in 3L and 4L, respectively.
Similarly, the most common treatment sequence changed after the novel agent introduction. Most patients received 1L (39.1%) only or up to 2L (22.6%) during the follow-up period; in SCT patients, the most common sequences changed to VT-based (48.1%) and VT-based with subsequent KR-based (12.1%) from T-based (11.7%) and T-based with subsequent V-based; in non-SCT patients, the most common sequence changed to VM-based (30.0%) and R-based from VM-based (24.8%) and chemo-based (11.4%).
TTNT decreased as LOT advanced from 571.5 days (time to 2L) to 289.1 days (time to 5+L), and TD of LOT ranged from 200.0 days to 283.7 days. SCT patients showed longer TTNT and TD than non-SCT patients, except for 1L where SCT patients showed shorter TD.
The median OS of all patients was 5.49 years, and SCT patients showed significantly longer OS (10.1 yrs) than non-SCT patients (4.0 yrs). The 5-year survival rate of all patients was 50.5%, and the rate decreased as LOT advanced from 36.5% (1L) to 21.1% (5+ L). SCT patients (47.7%) showed higher rate than non-SCT patients (33.8%), and the rate in SCT patients increased from 65.7% in 2010 to 76.5% in 2015.
All-cause HCRU was higher in the advanced LOTs compared to 1L, and healthcare cost increased with the LOT advancement after 1L initiation regardless of SCT status or novel agent introduction. The average length of hospital stay per admission was 22.4 days during the follow-up period, and the length of stay also increased as LOT advanced. The overall all-cause HCRU and cost were higher in non-SCT patients and after novel agent introduction. Similar trends were observed in MM-related HCRU and cost (Table 1).
Conclusion
This large population-based study found that the novel agent introduction has led to the increase of HCRU and costs of MM but was also associated with better treatment outcomes in terms of survival. The HCRU and costs increased with the advancement of LOT.
These findings suggest that a comprehensive understanding of economic burden and treatment outcomes would be required for evaluating the value of novel agent and selecting the optimal treatment options.