PF643 CHARACTERIZATION OF FRONTLINE TREATMENT PATTERNS AND THE PROPORTION OF PATIENTS REACHING SUBSEQUENT LINES OF THERAPY IN TRANSPLANT ELIGIBLE PATIENTS WITH NEWLY DIAGNOSED MULTIPLE MYELOMA

Background: It has been well documented that each additional line of treatment is associated with lower rates of deeper responses, shorter duration of treatment, and increased rates of toxicities/comorbidities in patients with multiple myeloma (MM; Yong K, et al. Br J Haematol 2016. 175[2]:252–264). These factors contribute to treatment discontinuation and impact the proportion of patients reaching subsequent lines of therapy. Aims: To characterize the rate of therapy attrition at relapse for patients with newly diagnosed MM (NDMM) who are transplant eligible in the United States. Methods: Patients with NDMM were identified from 3 US patient‐level data sources: the OPTUM™ Commercial Claims database (period: January 2000–March 2017), the OPTUM™ Electronic Medical Records (EMR) database (period: January 2007–March 2016), and the Surveillance, Epidemiology, and End Results (SEER)‐Medicare Linked database (period: January 2007–December 2014). Patients had 1) an index MM diagnosis on or after 1 January 2007, 2) medical prescription coverage in place at diagnosis, 3) no prior malignancies in the one‐year period prior to index diagnosis, 4) a one‐year look‐back period prior to index diagnosis, and 5) received ≥1 lines of therapy. Patients were considered transplant eligible if they received stem cell transplantation anytime during the follow‐up period. Baseline characteristics including comorbidities, index age, frontline treatment regimens and attrition rates at each subsequent line of therapy were characterized. Attrition was defined as the percentage of patients who did not have any recorded subsequent MM treatments as a result of death or lost to follow‐up in the database for any reason, including end of the database. Results: A total of 1,599 patients were included in this analysis. Baseline patient characteristics and pre‐existing comorbidities are summarized in Table 1 . The induction regimens used as frontline treatments included bortezomib/dexamethasone (22%), lenalidomide/dexamethasone (13%), bortezomib/lenalidomide/dexamethasone (25%), all other bortezomib combinations (20%), and other (20%). The proportions of patients observed to progress to each subsequent line of therapy are summarized in Table 2 . In total, 77% of patients received a second line of therapy, and only 55% received a third line treatment. The proportion of patients not receiving a subsequent line of therapy due to death is also summarized by lines of therapy in Table 2 . Summary/Conclusion: A substantial number of patients with NDMM who are transplant eligible did not receive subsequent lines of therapy, with attrition by lines of therapy ranging from 23–40%. The increase in attrition rates with each additional line of therapy underscores the need to utilize upfront therapy associated with optimal progression‐free survival. Further studies evaluating the etiologic basis for this unexpectedly high attrition rate are warranted.