Outcomes in Relapsed Multiple Myeloma in the UK: A Retrospective Observational Study
Authors: Yong Kwee , Percival Fran , Auger Martin , Basu Supratik , Chu Patrick , Aldouri Maadh , Gaugris Sabine 
Published: April 2020

Abstract
Recent availability of active drugs (proteasome inhibitor (PI) and IMiDs) for the treatment of multiple myeloma (MM) has changed the outlook for patients who relapse from plateau phase. While new regimens incorporating these agents prolong survival, they are relatively costly and may result in toxicities that impact on patient-centred outcomes and resource use. These health economic issues remain to be clarified in clinical practice. To better understand the treatment pathways and resource use in MM before the era of PI and IMiDs, a retrospective analysis was carried out in MM patients who experienced a 1st relapse between Feb 2001 and Dec 2007. Five UK centres were selected to ensure adequate geographical coverage and to provide observational data for patients being treated at secondary centres (ie not in trials or tertiary centres). Patient demographics, all medical interventions from 1st relapse until death, including hospital visits, and blood product use were obtained from medical records. Any treatment phases following the point at which patients received PI or IMiDs were excluded from the study. Data were collected from 78 patients in 1st relapse of whom 73 had died at the time of the study; data in 2nd relapse were available from 25 patients (of the 78 patients, 45 died before a 2nd relapse, and 8 were excluded from the analysis at 2nd relapse). Median age at 1st relapse was 62.8yrs (range: 43–89). Main isotypes were: IgG Kappa 35.5%, IgA Kappa 16.5%, IgA Lambda 15%, light chain 14%, IgG Lambda 13%. Almost two thirds of patients (64.1%) did not have an initial transplant, 25.7% had one or two transplants and 11.6% failed one or more bone marrow harvests. Median time to relapse was 19.2 months (IQ range: 2.2–130.3) from diagnosis and 10.3 months (IQ range: 2.7–36.2) from 1st relapse. As first line, the majority of patients had received alkylator ± steroid (26.9%) or VAD-based (25.6%), and only 15.4% had received Thalidomide-based regimens. In contrast, Thalidomide-based regimens were the most commonly used regimens at first relapse (n=38, 48.7%), followed by alkylator ± steroid (n=15, 19.2%). Progression free survival (PFS) from 1st relapse was 8.5 months (IQ range: 0.6–43.7). At 2nd relapse the most common regimen was Thalidomide-based (n=13, 52%). PFS from 2nd relapse was 10.6 months (0.5–31.2). Median treatment free interval (TFI) was 17.5 months (range 0–130.3) from end of initial treatment to 1st relapse and 9.7 months (range 1–47.7) from end of 1st relapse to 2nd relapse. Median overall survival was 32.8 months (IQ range: 14.2–49.6) from diagnosis and 10.1 months (IQ range: 3.6–20.9) from 1st relapse. These figures were comparable with published data, indicating that our group of patients was representative of MM patients receiving treatment at relapse. The mean number of hospital visits per patient per year was 14.8 (SD 12.1) for patients in 1st relapse and 10.1 (SD 4.2) for those in 2nd relapse. Blood products were administered in 38 (49%) patients in 1st relapse, and these patients received a mean of 8.5 units per patient per year. Thirteen (52%) patients at 2nd relapse required blood transfusions. These results provided baseline real-life data on the outcomes in MM patients relapsing from plateau phase before the era of PI and IMiDs. Similar analyses in patients treated with PI and IMiDs at relapse will help to determine the impact of these agents on healthcare resource use in the context of increased survival.