Real-world treatment patterns, outcomes, and economic costs by lines of therapy in patients with newly diagnosed multiple myeloma: a nationwide population-based cohort study in South Korea.

Purpose: Given the notable increase in the incidence of multiple myeloma (MM) in Asia and advent of innovative treatments, this study aims to provide a comprehensive understanding of the treatment patterns, outcomes, and economic burden of MM across the lines of therapy (LOTs) in South Korea.

Methods: This retrospective cohort study was conducted using data from the National Health Insurance claims data provided by the Health Insurance Review and Assessment Database. An identification algorithm was developed to detect the regimens and LOTs. Treatment patterns and outcomes were assessed as real-world treatment sequence, treatment duration (rwTD), time to next-line treatment (rwTTNT), and overall survival (rwOS). Economic burden was assessed as healthcare resource utilization (HCRU) and the cost incurred per person per month.

Results: This study included 11,450 patients who were newly diagnosed with MM between January 2010 and December 2019. The observed real-world LOT patterns reflect the changes in South Korea's reimbursement scheme. Mean treatment-free intervals decreased from 11.59 months (SD 16.23) to 2.77 months (SD 6.14) from the first LOT (LOT 1) to LOT 5. Median rwTTNT decreased from 26.61 months (95% CI: 25.69-27.57) to 12.40 months (95% CI: 11.55-13.49), and median rwOS decreased from 61.88 months (95% CI: 59.11-65.46) to 13.65 months (95% CI: 11.88-16.22). The HCRU and associated costs increased substantially with the LOT advancement.

Conclusion: This large-scale observational study offers comprehensive insights into the real-world treatment of MM in South Korea. The study findings highlight the progressive nature of MM and increasing economic burden of advanced lines of treatment, underscoring the necessity for optimized treatment strategies.