Burden Of Illness and Treatment Patterns For Patients With Multiple Myeloma In a US Integrated Healthcare System

Multiple myeloma (MM) is the 2^nd most common hematological malignancy. The objective of this study was to evaluate the burden of illness within the MM population and describe the patient characteristics, healthcare resource utilization, and 1^st and 2^nd line treatment patterns for patients diagnosed with MM in Kaiser Permanente Southern California (KPSC) region and ineligible for stem cell transplant (SCT) in an integrated system in the US.

A retrospective database analysis was conducted using data between 1/1/2006 to 12/31/2010 from KPSC to identify incident MM patients. Patients ≥18 years, with a diagnosis of incident MM from the KPSC cancer registry and with no record of SCT, and who had continuous membership and drug benefit eligibility 6 months prior to the index date were selected into our study cohort. Index date was defined as the start date of the 1^st line systemic agent. Baseline characteristics, such as comorbidities, related conditions, concomitant therapies, and healthcare resource use were captured within 6 months prior to and post the index date for all patients. Patients were followed until death, disenrollment from the health plan, or study end date (12/31/2011), whichever came first. Lab data, diagnosis codes, and chart review were used to establish disease progression using the IMWG criteria. A multivariate stepwise logistic regression model was used to evaluate characteristics such as age, gender, race, comorbid conditions, and concomitant medications associated with 1^st and 2^nd line treatment choices. Lines of therapies were identified based on disease progression and change of regimen. Regimens were categorized into bortezomib containing regimens (BCR), lenalidomide containing regimens (LCR), thalidomide containing regimens (TCR), novel combination regimens (NCR) containing at least one proteasome inhibitor (PI), eg, bortezomib and one immunomodulatory drug (IMiD) (eg, thalidomide or lenalidomide), and other regimens containing no novel agent (OTHs).

920 patients were identified with incident MM in the KPSC region during our study time period. 599 patients meeting the inclusion criteria were followed for a mean of 29 months (2.41 yrs); 53% were males; the mean age at index date was 70 years old. Majority of the patients had chronic kidney disease (CKD) stage 2 or 3 (34% and 29%, respectively). The most common comorbidities were anemia (61.8%), some form of fracture (17.4%), bone metastasis (5.18%), hypercalcemia (8.68%), pneumonia (15%), diabetes (26%), and chronic pulmonary disease (29%) in the prior 6 months. First-line therapy in the 599 patients included BCR (n=80, 13.3%), LCR (n=97, 16.1%), TCR (n=232, 39%), NCR (n=4, 0.67%), or other (n=186, 31%). A total of 238 patients (40%) continued to 2^nd line therapy: 57 patients were prescribed with BCR, 105 patients with LCR, 36 with TCR, 9 patients with NCR, and 31 with OTH. Overall use of TCR declined from 46% in 2006 to 11% in 2010, while the use of BCR and LCR increased from 17% and 8%, respectively, in 2006 to 37% and 30%, respectively, in 2010.

Patients who initiated BCR at 1^st line were more likely to be on bisphosphonate therapies (OR: 5.12, CI 2.26-11.6) for deep vein thrombosis or pulmonary embolism (OR: 2.81, CI 1.15-6.89) also had more outpatient visits versus patients on other therapies (OR: 1.05, CI 1.01-1.09). Patients who initiated NCR were less likely to have anemia versus patients initiating other therapies (OR: 0.56, CI 0.39-0.82). Patients who initiated TCR were less likely to have prior fractures (OR: 0.54, CI 0.34-0.88) and chronic pulmonary diseases (OR: 0.44, CI 0.28-0.71) versus patients initiating other therapies as 1^st line. Patients initiating LCR as 1^st line therapy were more likely to be anemic and have bone metastases, and less likely to have renal disease or MM specific hospitalizations versus other 1^st line therapies. Patients initiating BCR as 2^nd line therapy were generally younger (age <65 yrs; OR: 0.97, CI 0.95-1.00).

The burden of illness for patients newly diagnosed with MM is high. Our study found that factors such as age and comorbidities, such as anemia, fractures, bone metastases, chronic pulmonary disease, and renal disease might be associated with the use of different 1^st and 2^nd line therapies. Further investigation of these factors and their impact on treatment outcome and resource utilization could help optimize management of MM patients.

Rashid:Kaiser Permanente Southern California: Employment. Wu:Kaiser Permanente Southern California: Employment. Su:BMS: Employment, Equity Ownership. Fong:Kaiser Permanente Southern California: Employment.