Background: Negligible real-world evidence exists for later line treatment of multiple myeloma (MM) to assist treatment decisions or reimbursement models, such as episode-based payments.
Objective: To describe the treatment patterns and clinical/economic outcomes when pomalidomide or carfilzomib is used for relapsed/refractory MM.
Methods: A U.S. claims database was used to identify MM patients with an initial pomalidomide or carfilzomib claim (index date) between February 1, 2013, and February 28, 2015, which was assumed to be relapse therapy. Treatment regimens were defined as all MM chemotherapy observed within 60 days of index. Patients receiving pomalidomide and carfilzomib within 60 days of index were excluded. Time to next treatment (TTNT), a progression proxy, was defined as the addition of a new agent > 60 days from index or as treatment restart following a > 90-day therapy gap. Cost estimations used plan-allowed amounts. Descriptive statistics were used to compare outcomes between treatment groups, and regression models were used to adjust for baseline patient characteristics.
Results: There were 454 patients initiating treatment with pomalidomide (n = 264) or carfilzomib (n = 190) during the index period. The most frequent initial regimens for pomalidomide patients included pomalidomide + dexamethasone (47.0%) and pomalidomide alone (33.0%); the most frequent regimens for carfilzomib patients were carfilzomib alone (45.3%) and carfilzomib + dexamethasone (14.7%). The most frequent next line treatment for pomalidomide patients who progressed was the addition of (14.0%) or switch to (15.0%) carfilzomib ± dexamethasone and for carfilzomib patients, the most frequent next line treatment was pomalidomide + dexamethasone (9.3%) and carfilzomib alone or carfilzomib + dexamethasone + cyclophosphamide (6.7% each). The median (95% CI) TTNT for pomalidomide patients was 11.9 (10.7-14.8) compared with 9.4 (7.7-10.0) months for carfilzomib (P = 0.060). For patients followed to progression (pomalidomide: n = 100, 37.9%; carfilzomib: n = 75, 39.5%), mean TTNT was longer for patients initiating therapy with pomalidomide (6.9 months) versus carfilzomib (5.3 months, P = 0.016). When adjusted for baseline confounders, pomalidomide patients had a nonsignificant longer time to a subsequent treatment line. Inpatient encounters observed during the index line were very low (mean = 1) for both groups; outpatient encounters were fewer in pomalidomide patients. Adjusted analyses revealed inpatient encounters were higher (P = 0.005), while outpatient use was lower in pomalidomide patients (P = 0.006). Unadjusted median costs incurred during the initial line were similar between the 2 groups (pomalidomide: $102,805; carfilzomib: $127,203; P = 0.110) but significantly lower in pomalidomide patients after adjusting for baseline characteristics (P = 0.013). Unadjusted per patient per month (PPPM) costs incurred over the entire follow-up period were lower in pomalidomide-initiated patients ($18,298 vs. $24,734, P = 0.001) but not statistically significant in adjusted analyses (P = 0.230).
Conclusions: A longer time to a subsequent line of therapy was observed in pomalidomide patients compared with carfilzomib patients, although the difference lost significance in adjusted analyses. Compared with carfilzomib, pomalidomide patients were observed to have lower unadjusted median PPPM costs over the entire post-index period and lower adjusted mean monthly costs during initial therapy.
Disclosures: Funding for this study was provided by Celgene. Chen, McGuiness, and Wade are employees of QuintilesIMS, which was contracted by Celgene to undertake this research. McGuiness also owns stock in Pfizer. Parikh, Abouzaid, Purnomo, and Hussein are employees of Celgene and participated fully in the development and approval of the manuscript. Portions of the results of this research were previously presented at the American Society of Clinical Oncology (ASCO) 2016 Annual Meeting; June 3-7, 2016; Chicago, Illinois. Study concept and design were contributed by Chen, Parikh, Abouzaid, McGuiness, and Wade. Chen and McGuiness took the lead in data collection, along with Wade, and data interpretation was performed by Hussein and Wade, with assistance from the other authors. The manuscript was written by McGuiness, Chen, and Wade, with assistance from Parikh and Abouzaid, and revised by McGuiness and Hussein, along with the other authors.