Adoption of triplet therapy and clinical outcomes in routine practice among newly diagnosed multiple myeloma patients not receiving frontline stem cell transplant in the USA.

ABSTRACT

BACKGROUND: Immunomodulator (IMID) and proteasome inhibitor (PI) triplet frontline therapy (FT) in newly diagnosed multiple myeloma (NDMM) trials improve overall survival (OS); reported outcomes in routine practice are lacking. Authors compared outcomes in NDMM patients in the USA by use of triplet vs doublet FTs. METHODS: In this retrospective study of NDMM patients without FT transplant between 1/1/2008 and 6/30/2017, FT was categorized as PI+IMID-triplet (≥ 3 drugs including PI+IMID), non-PI+IMID-triplet (≥ 3 drugs, not PI+IMID), doublet (≤ 2 drugs). Univariate and multivariate analyses identified FT triplet predictors and compared time-to-next-treatment (TTNT)/OS. RESULTS: Among 4,982 NDMM patients, 68% and 32% initiated doublet and triplet FTs (PI+IMID 36% in 2017). Triplet FT predictors included age, cytogenetics, ISS stage, certain CRAB symptoms. Median TTNTPI+IMID-triplet = 18.9 months vs 13.7 (non-PI+IMID-triplet) and 16.5 months (doublet) FTs (P< 0.01); adjusted HRPI+IMID-triplet = 0.86; P= 0.009; HRnon-PI+IMID-triplet = 1.10; P = 0.083 vs doublet FT. Median OSPI+IMID-triplet = 58.7 months vs 43.6 (non-PI+IMID-triplet) and 45.7 months (doublet) FTs (P< 0.01); adjusted HRPI+IMID-triplet = 0.83; P= 0.016; HRnon-PI+IMID-triplet = 1.02; P = 0.727 vs doublet FT. CONCLUSION: PI+IMID-triplet FT is not utilized for most non-frontline-transplant NDMM patients in routine care but is associated with prolonged TTNT/OS.