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COMPARATIVE EFFECTIVENESS OF TRIPLETS CONTAINING BORTEZOMIB (B), CARFILZOMIB (C), DARATUMUMAB (D), OR IXAZOMIB (I) IN RELAPSED/REFRACTORY MULTIPLE MYELOMA (RRMM) IN ROUTINE CARE IN THE US

PS1419

Davies, F.1; Rifkin, R.2; Costello, C.3; Usmani, S.4; Abonour, R.5; Palumbo, A.6; Romanus, D.6; Hajek, R.7; Terpos, E.8; Stull, D. M.6; Huang, H.6; Leleu, X.9; Berdeja, J.10; Lee, H.11; Weisel, K.12; Thompson, M.13; Boccadoro, M.14; Zonder, J.15; Cook, G.16; Puig, N.17; Vela-Ojeda, J.18; Skacel, T.6; Farrelly, E.19; Raju, A.19; Blazer, M.19; Chari, A.20

doi: 10.1097/01.HS9.0000563952.08050.24
Poster Session II: Myeloma and other monoclonal gammopathies - Clinica
Free

1Myeloma Institute, University of Arkansas for Medical Sciences, Little Rock

2Rocky Mountain Cancer Centers, Denver

3Moores Cancer Center, University of California, San Diego

4Carolinas Healthcare System, Charlotte

5Indiana University, Indianapolis

6Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited, Cambridge, United States

7University Hospital Ostrava, Ostrava, Czech Republic

8University of Athens School of Medicine, Athens, Greece

9CHU la Miletrie, Poiters, France

10Tennessee Oncology, Sarah Cannon Research Institute, Nashville

11University of Texas, MD Anderson Cancer Center, Houston, United States

12Department of Oncology, Hematology and Bone Marrow Transplantation with Section of Pneumology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

13Aurora Cancer Center, Milwaukee, United States

14Azienda Ospedaliera Citta della Salute e della Scienza, Torino, Italy

15Karmanos Cancer Institute, Detroit, United States

16Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom

17Salamanca University Hospital, Salamanca, Spain

18Hospital de Especialidades Centro Medico Nacional la Raza, Mexico City, Mexico

19Xcenda, Palm Harbor

20Icahn School of Medicine at Mount Sinai, New York, United States

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Background:

Triplet regimens (TpRs) with a bortezomib-based backbone have traditionally been the most commonly used triplets in RRMM in United States (US). The advent of novel proteasome inhibitors (PIs), immunomodulators (IMIDs), and monoclonal antibodies in MM are rapidly shifting the RRMM treatment paradigm. Lack of head-to-head trials of novel agents versus bortezomib-based triplets used for registration purposes renders treatment choice for RRMM patients (pts) difficult, highlighting a need for real-world evidence.

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Aims:

To conduct a comparative effectiveness real-world analysis of triplet regimens containing bortezomib (B), carfilzomib (C), daratumumab (D), or ixazomib (I) in RRMM.

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Methods:

RRMM pts with ≥1 prior line of therapy (LOT) initiating a TpR on/after 1/1/2014 were followed retrospectively in Optum's de-identified electronic health record dataset (2007-2018) - a large US database. TpRs were categorized into B-,C-,D-,I-based; treatment groups were mutually exclusive. Median duration of therapy (DOT) and time-to-next-treatment (TTNT) were estimated using Kaplan-Meier methods and compared using stratified (by LOT) ± confounder adjusted Cox proportional hazard models. We used a repeated measures analysis of pt-LOTs with robust sandwich estimators to account for inclusion of pts in multiple LOTs. Observations were censored at time of loss to follow up (f/u)/end of study period (3/31/2018). A separate subgroup analysis of LOTs 2-3 was also performed.

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Results:

Overall, 1345 pts with 1753 pt-LOTs (B-based, n = 746; C-based, n = 522; D-based, n = 269; I-based, n = 216) were included. B-/C-/D-/I-based TpRs consisted of an alkylator in 38/27/6/6% or an IMID-backbone in 58/71/93/94% (lenalidomide, 47/42/37/71%; pomalidomide, 7/28/55/21%; thalidomide, 4/1/1/2%), respectively; 81/60/37/63% pts received B-/C-/D-/I-based TpRs in LOT 2-3. Median age was 70/65/68/69 years and 33/20/25/38% pts were ≥75 years old in the B-/C-/D-/I-based TpR group, respectively. CRAB symptoms were more common in the B-/C-/D- (82/87/84%) than in the I-based group (64%) at baseline. Overall, more pts in the C- (26%) had high risk disease (del 17p and/or t(4;14) and/or t(14;16) and/or 1q21 gain), followed by D- (23%) vs in B- (16%) and I-based groups (14%), although 62/64/69/75% pts in each group had missing cytogenetic risk data. More pts in the D-based group (87%) were IMID and/or PI refractory, followed by C- (84%), I- (65%), and B-based (38%) groups. Double refractory status was present in 7/31/23/23% pts in the B-/C-/D-/I-based groups. Overall, at median f/u of 16.3/13.3/8.6/10.2 months (mos) in the B-/C-/D-/I-based groups, unadjusted median DOTs were: 8.0/6.0/7.1/8.4 mos and TTNTs were: 9.8/6.7/8.0/11.1 mos, respectively. In the subgroup analysis (LOT 2-3), unadjusted median DOTs in the B-/C-/I-based TpRs were: 8.4/6.3/8.4 mos and TTNTs were: 10.8/7.8/12.7 mos, respectively, and not estimable in the D-triplet group.

Figure

Figure

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Summary/Conclusion:

In stratified analyses, compared to B-, I-based triplets had a significantly decreased risk of starting next LOT/death in LOTs 2+ overall, and in LOTs 2-3. After further adjusting for baseline confoundersb, I- and D-based triplets reduced the risk in LOTs 2+ overall, and in LOTs 2-3, I-based triplets significantly reduced the risk of starting next LOT/death versus B-based triplets. Limitations include residual confounding due to unobserved treatment selection biases that are inherent to any non-randomized, observational study. Further research into therapy sequencing, as the RRMM treatment landscape evolves, is necessary.

Copyright © 2019 The Authors. Published by Wolters Kluwer Health Inc., on behalf of the European Hematology Association.