Clinical Characteristics and Treatment of Patients with Multiple Myeloma Using the Japan Medical Data Center Database

Background: The incidence of Multiple Myeloma (MM) is increasing in Asia, although it's still less common compared to the incidence in Western countries. Information on clinical characteristics and current treatments is important to inform future clinical research.

Purpose: To describe the clinical characteristics and treatment patterns of patients aged ≥18 years with MM in Japan.

Methods: We conducted a retrospective cohort study using the Japan Medical Data Center (JMDC) database, an employment insurance claims database covering approximately 3.78 million patients (non-government employees and their family members, <75 years of age) from July 1, 2009-December 31, 2016. Adult patients with a confirmed diagnosis of MM as well as at least one treatment for MM after the initial diagnosis were included in the analysis. Patients with any existing primary cancer other than MM were excluded. Eligible patients were followed up until death, or study end, whichever came first.

Results: A total of 164 confirmed MM patients were include in the analyses, of which 73% were employees, 27% were family members, and 65% were male. 77% of patients were aged 36-65 years, reflecting the characteristics of the employment database. The median follow up period after the diagnosis was 26 months (range 1-75). The most common co-morbidities at diagnosis were hypertension (36%), bone fracture (21%), peripheral neuropathy (15%), renal failure (11%) and anemia (10%). The median time from diagnosis until commencing treatment was 27 days (range 0-1937), with 66% of patients commencing treatment within 0-90 days after diagnosis. 43% of patients (47% of employees versus 32% of family members) commenced initial MM treatment with bortezomib: most frequently bortezomib + dexamethasone without (21%, 33/160) or with (22%, 35/160) chemotherapy. Three patients received radiotherapy and one received autologous stem cell transplant as initial treatment. Median duration of treatment with a bortezomib-based regimen was 156 days (range 18-1270). Almost half (49%) of all patients received initial treatment with steroids alone. Median duration of non-bortezomib based initial treatment was 120 days (range 1-1837). By the end of the study period, 34% of patients were still using first-line treatment, 32% received no further treatment, 15% began second-line therapy, 12% received an autologous stem cell transplant, 4% commenced radiotherapy, 2% were re-treated and 1% died. Second-line treatment was with bortezomib-based therapies in 46% (11/24) of patients. A total of 23% of all patients received an autologous stem cell transplant over the study period. 20% (34/164) of patients developed at least one second tumor over the observation period: 17 patients developed a hematologic malignancy and 22 developed a solid tumor.

Conclusion: The JDMC database covers approximately 1% of the Japanese population and all members are <75 years of age. Patients with MM are therefore likely to be younger with less advanced disease than the general population. Half of MM patients were initially treated with steroids, with 43% receiving bortezomib. The study suggests a relatively low rate of progression to advanced line treatment or retreatment in this young cohort of Japanese patients with MM.