Observational Prospective Registry for the Assessment of the Clinical Impact of Starting Anti-Myeloma Treatment at Biological Relapse

Introduction: Despite the great medical advances associated with the introduction of thalidomide, bortezomib (BORT), and lenalidomide (LEN) for the treatment of multiple myeloma (MM), it remains an incurable disease. Most patients (pts) show disease progression, consistent with the clinical evolution of MM, and only a low percentage achieve long-term responses and extended progression-free survival (PFS). The heterogeneous nature of MM in both the clinical and biological setting is reflected in the heterogeneity of MM relapses. The International Myeloma Workshop Consensus Panel (Rajkumar, Blood 2011) states that treatment (Tx) shall begin either at clinical relapse with symptoms (clinR), or in the event of asymptomatic relapse with significant paraprotein relapse, biological relapse (BR). The purpose of this Spanish registry is to describe MM relapse patterns comparing the impact of Tx decisions in pts who meet the criteria for biological relapse (BR) according to IMWG criteria with those in whom Tx was delayed until clinical relapse (clinR). Here, the preliminary results of this study are presented.

Methods: MM pts in (or previous to) first or second BR who have achieved ≥ PR since their last Tx are eligible for inclusion in this observational prospective registry at the time BR is detected. Evaluations performed at least bi-monthly are mandatory. A total of 41 Spanish sites participated in the registry following approval from their independent ethics committees, with 410 pts expected to be included, without physician’s decision of prescribing Tx affecting the inclusion. The main objective of the registry is to assess the time to progression (TTP) from the start of anti-MM Tx at the onset of asymptomatic BR vs. the start of Tx at the time of clinR. Secondary objectives are to describe demographics of BR; to assess the median time elapsing from BR to clinR; to assess overall response rate (ORR), event-free survival (EFS), PFS, overall survival (OS) at BR and at clinR (if appropriate); to asses safety and quality of life (QoL) using 2 validated questionnaires (European Organisation for Research and Treatment of Cancer [EORTC] QLQ-C30 and QLQ-MY24); to document the tolerability profile of the Tx; and to describe the use of associated resources. Here, we summarize baseline characteristics and preliminary results from 83 pts (out of 126 registered pts) who had basal data in the registry at the time of this report.

Results: Overall, 79% of pts presented with a BR and 21% were in a bi-monthly watchful waiting follow up. The mean age of pts was 67 years, 53% were female, 57% were in first relapse, 43% and 27% had an ECOG performance status (PS) of 0 and 1, respectively, while the ECOG PS was unknown in 30% of pts at the time of this report. In total, 30% of pts had ISS stage I, 26% had ISS stage II, and 22% had ISS stage III, while ISS stage data were not available or unknown for 12% and 10% of pts, respectively. MM types were IgG Κ (37% of pts), IgG λ (23%), IgA Κ (13%), IgA λ (9%), and type was unknown in 17% of pts. 28% of IgG/IgA MM types were Bence-Jones. Cytogenetic risk assessments were available in 66% of pts. Among those pts with a BR, 51% received active Tx without waiting for a ClinR. First-line Tx was BORT-based in 70% of pts. Overall, 55% of pts had undergone autologous stem cell transplantation, 15% had received consolidation Tx and 34% had received maintenance Tx. After first-line Tx, 17% of pts achieved a stringent complete response (sCR), 31% achieved a CR, 24% achieved a very good partial response (VGPR), and 10% achieved a PR. The median time to BR was 24.53 months. Most (63%) pts who registered after second relapse received LEN-based Tx.

Conclusions: To our knowledge, this is the first prospective study in MM to evaluate BR as well as the effects of Tx based on the decision to start Tx at BR vs. clinR. In this preliminary cohort, the physicians’ decision to start active Tx at BR, before the onset of clinR in 50% of cases, was noteworthy. Further follow-up is needed to identify the differences between these two strategies. Updated clinical results will be presented at the meeting.

MM-BR Study, Spanish Myeloma Group-GEM/PETHEMA

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