Outcome of carfilzomib/pomalidomide-based regimens after daratumumab-based treatment in relapsed multiple myeloma: A Canadian Myeloma Research Group Database analysis.

INTRODUCTION: Although daratumumab-containing regimens improve multiple myeloma (MM) outcomes, recurrence is inevitable. METHODS AND OBJECTIVE: We performed a retrospective study using the Canadian Myeloma Research Group Database to benchmark the efficacy of carfilzomib- or pomalidomide-based therapies immediately following progression on daratumumab treatment. RESULTS: We identified 178 such patients; median number of prior lines of therapy was 3, 97% triple-class exposed, and 60% triple-class refractory. In our cohort, 75 received a subsequent carfilzomib-based therapy, 79 received a pomalidomide-based therapy, and 24 received a treatment with both immunomodulatory drug (IMiD) and proteasome inhibitor (PI) using carfilzomib and/or pomalidomide. The median progression-free survival (PFS) and overall survival (OS) for the entire cohort were 4.5 and 14.2 months, respectively. Carfilzomib-based therapy yielded a median PFS and OS of 4.5 and 10.2 months, respectively, compared to 5.2 and 21.7 months for pomalidomide-based therapy. Patients who received both IMiD and PI with carfilzomib and/or pomalidomide had a median PFS and OS of 4.1 and 14.5 months, respectively. CONCLUSION: Our observations demonstrate the poor outcome of MM patients when standard regimens based on carfilzomib and/or pomalidomide are utilized directly after daratumumab-based therapy given in the relapsed setting. Novel therapies, including immune therapies, are urgently needed to improve the outcomes of these daratumumab-exposed patients.

Outcomes of daratumumab in the treatment of multiple myeloma: A retrospective cohort study from the Canadian Myeloma Research Group Database.

Daratumumab (dara) has significantly altered the therapeutic landscape of multiple myeloma (MM), especially in the relapsed setting. This study aimed to evaluate the outcomes of dara-containing regimens in the Canadian real-world setting among relapsed and refractory MM available within the national Canadian Myeloma Research Group Database (CMRG-DB). A total of 583 MM patients who received dara-based therapy in second-line or later treatment were included. After a median follow-up of 17.5 months, the median progression-free survival (PFS) and overall survival (OS) for the entire cohort were 13.1 and 32.9 months, respectively. The median PFS and OS were 23.5 and 49.1 months in second-line treatment and decreased to 12.8 and 43.0 months in third-line and 7.0 and 20.5 months in fourth-line treatment respectively. Dara in monotherapy with or without corticosteroids after a median of four prior lines of therapy resulted in a median PFS of 3.9 months and a median OS of 17.1 months. The addition of bortezomib, lenalidomide or pomalidomide to dara resulted in an improved median PFS and OS of 8.3 and 26.2 months; 26.8 and 43.0 months; and 9.7 and 31.4 months respectively. These retrospective data from the CMRG-DB suggest that outcomes are superior when dara is used in combination and in earlier lines of treatment.

Real-world outcomes with bortezomib-containing regimens and lenalidomide plus dexamethasone for the treatment of transplant-ineligible multiple myeloma: a multi-institutional report from the Canadian Myeloma Research Group database.

Bortezomib-containing regimens (BCRs) represented standard, first-line therapy for transplant-ineligible multiple myeloma (TIMM) in Canada until the introduction of lenalidomide and low-dose dexamethasone (Ld). However, little comparative data exist to inform the selection of regimens. We assessed the outcomes for TIMM patients treated with cyclophosphamide, bortezomib and dexamethasone or prednisone (CyBorD/P), bortezomib, melphalan and prednisone (VMP), bortezomib and dexamethasone or prednisone (VD/P) and lenalidomide and low-dose dexamethasone (Ld) using the Canadian Myeloma Research Group database. Of 1156 TIMM patients evaluated, 82% received bortezomib combinations while 18% received Ld. Median progression-free survival (PFS) was 21·0, 21·1, 13·2 and 28·5 months (P = 0·0002) and median overall survival (OS) was 52·0, 63·6, 30·8 and 65·7 months (P < 0·0001) in the CyBorD/P, VMP, VD/P and Ld groups respectively. There was no significant difference in PFS and OS between the two triplet bortezomib regimens (VMP and CyBorD/P). Ld was associated with a longer PFS but not a significantly superior OS to date. Outcomes with the bortezomib-steroid doublet were inferior (VD/P). However, multivariable analysis identified features related to disease biology as the most important prognostic factors for PFS and OS. Such factors, as well as those affecting the physician's choice of regimen, are likely to influence the results observed with different regimens. This study demonstrated real-world outcomes in TIMM similar to those reported in clinical trials.

The impact of lenalidomide maintenance on second-line chemotherapy in transplant eligible patients with multiple myeloma.

OBJECTIVES: To understand the impact of therapy sequencing on progression-free (PFS) and overall survival (OS) for the treatment of multiple myeloma (MM). The use of daily, low-dose, lenalidomide maintenance (LM) has raised concern for fostering resistance, preventing its use in the relapsed setting. METHODS: We conducted a retrospective analysis of survival outcomes from the Canadian Myeloma Research Group Database. Patients were grouped based on receipt of LM after autologous stem cell transplant and receipt of lenalidomide in second-line therapy, 575 patients were included. RESULTS: Patients treated with LM had statistically similar 2nd PFS when re-exposed to lenalidomide in second-line therapy compared to those receiving non-lenalidomide-containing regimens (10.2 vs 14.0 months, P =.53). This cohort also had the longest 2nd OS, 18 months longer than patients treated with LM who did not receive lenalidomide at relapse (55.3 vs 37 months, P =.004). Patients treated with LM also demonstrated deeper responses to second-line therapy than their non-LM counterparts. CONCLUSION: Our data suggest that patients progressing on LM who receive lenalidomide-containing therapy at first relapse have comparable 2nd PFS and better 2nd OS compared to non-lenalidomide-containing second-line regimens. Identification of patients mostly likely to benefit from further lenalidomide-containing therapy is paramount.

Retrospective study of treatment patterns and outcomes post-lenalidomide for multiple myeloma in Canada.

Lenalidomide is an important component of initial therapy in newly diagnosed multiple myeloma, either as maintenance therapy post-autologous stem cell transplantation (ASCT) or as first-line therapy with dexamethasone for patients' ineligible for ASCT (non-ASCT). This retrospective study investigated treatment patterns and outcomes for ASCT-eligible and -ineligible patients who relapsed after lenalidomide as part of first-line therapy, based on data from the Canadian Myeloma Research Group Database for patients treated between January 2007 and April 2019. Among 256 patients who progressed on lenalidomide maintenance therapy, 28.5% received further immunomodulatory derivative-based (IMiD-based) therapy (lenalidomide/pomalidomide) without a proteasome inhibitor (PI) (bortezomib/carfilzomib/ixazomib), 26.2% received PI-based therapy without an IMiD, 19.5% received both an IMiD plus PI, 13.5% received daratumumab-based regimens, and 12.1% underwent salvage ASCT. Median progression-free survival (PFS) was longest for daratumumab-based therapy (22.7 months) and salvage ASCT (23.4 months) and ranged from 6.6 to 7.3 months for the other treatments (P < .0001). Median overall survival (OS) was also longest for daratumumab and salvage ASCT. A total of 87 non-ASCT patients received subsequent therapy, with 66.7% receiving bortezomib-based therapy and 13.8% receiving other PI-based therapy. Median PFS was 15.4 and 24.8 months for bortezomib-based and other PI-based therapy, respectively (P = .404). During most of the study period, daratumumab was not funded; in this setting, switching to a different therapeutic class following relapse on lenalidomide produced the longest remissions for non-ASCT patients. Further prospective studies are warranted to determine optimum treatment following relapse on lenalidomide, especially in the light of increased access to daratumumab.

Weekly carfilzomib plus cyclophosphamide and dexamethasone in the treatment of relapsed/refractory multiple myeloma: Final results from the MCRN-003/MYX.1 single arm phase II trial.

The MCRN-003/CCTGMYX.1 is a single arm phase II trial of weekly carfilzomib, cyclophosphamide and dexamethasone (wKCd), exploring a convenient immunomodulator (IMiD)-free regimen in relapsed myeloma. Weekly carfilzomib (20/70 mg/m2 ), dexamethasone 40 mg and cyclophosphamide 300 mg/m2 was delivered over 28-day cycles. The primary endpoint was overall response after four cycles. Secondary endpoints included toxicity, response depth, PFS and OS. Exploratory endpoints included the impact of cytogenetics, prior therapy exposure and serum free light chain (sFLC) escape; 76 patients were accrued. The ORR was 85% (68% ≥very good partial response [VGPR] and 29% ≥complete response [CR]). The median OS and PFS were 27 and 17 months respectively. High-risk cytogenetics conferred a worse ORR (75% vs. 97%, p = .013) and median OS (18 months vs. NR, p = .002) with a trend toward a worse median PFS (14 vs. 22 months, p = .06). Prior proteasome inhibitor (PI) or lenalidomide did not influence OS or PFS. The sFLC was noted in 15% of patients with a median PFS of 17 months when included as a progression event. The most common ≥ grade 3 non-hematologic adverse events were infectious (40%), vascular (17%) and cardiac (15%). The wKCD is a safe and effective regimen in relapse, especially for patients ineligible for lenalidomide-based therapies.

Accuracy of the Ottawa score in risk stratification of recurrent venous thromboembolism in patients with cancer-associated venous thromboembolism: a systematic review and meta-analysis.

In patients with cancer-associated venous thromboembolism, knowledge of the estimated rate of recurrent events is important for clinical decision-making regarding anticoagulant therapy. The Ottawa score is a clinical prediction rule designed for this purpose, stratifying patients according to their risk of recurrent venous thromboembolism during the first six months of anticoagulation. We conducted a systematic review and meta-analysis of studies validating either the Ottawa score in its original or modified versions. Two investigators independently reviewed the relevant articles published from 1st June 2012 to 15th December 2018 and indexed in MEDLINE and EMBASE. Nine eligible studies were identified; these included a total of 14,963 patients. The original score classified 49.3% of the patients as high-risk, with a sensitivity of 0.7 [95% confidence interval (CI): 0.6-0.8], a 6-month pooled rate of recurrent venous thromboembolism of 18.6% (95%CI: 13.9-23.9). In the low-risk group, the recurrence rate was 7.4% (95%CI: 3.4-12.5). The modified score classified 19.8% of the patients as low-risk, with a sensitivity of 0.9 (95%CI: 0.4-1.0) and a 6-month pooled rate of recurrent venous thromboembolism of 2.2% (95%CI: 1.6-2.9). In the high-risk group, recurrence rate was 10.2% (95%CI: 6.4-14.6). Limitations of our analysis included type and dosing of anticoagulant therapy. We conclude that new therapeutic strategies are needed in patients at high risk for recurrent cancer-associated venous thromboembolism. Low-risk patients, as per the modified score, could be good candidates for oral anticoagulation. (This systematic review was registered with the International Prospective Registry of Systematic Reviews as: PROSPERO CRD42018099506).

Post-transplant consolidation plus lenalidomide maintenance vs lenalidomide maintenance alone in multiple myeloma: A systematic review.

BACKGROUND: In newly diagnosed multiple myeloma (NDMM), autologous stem cell transplantation (ASCT) remains the standard approach for transplant-eligible patients. To control the inevitable relapse, post-transplant consolidation/maintenance strategies are commonly used. However, the benefit of post-transplant consolidation is still uncertain METHOD: We conducted a systematic review of phase II/III studies to compare the efficacy of post-ASCT consolidation plus lenalidomide maintenance (CON+LEN) vs lenalidomide maintenance alone (LEN alone) in NDMM. A meta-analysis using fixed and random effects models was performed. RESULTS: Fourteen studies were included with 2275 participants with NDMM treated with ASCT and lenalidomide maintenance. Two groups were identified: CON+LEN group (n = 1102) and LEN alone group (n = 1173). There was no statistically significant difference in the complete response rate between the two groups [RR = 1.1; 95% CI: 0.83-1.44; P = .490]. Interestingly, we found that very good partial response or better rate is around 1.5-fold significantly higher in the CON+LEN group compared to LEN alone group [RR: 1.46; 95% CI: 1.25-1.70; P < .0001]. However, there was no significant difference between the two groups regarding PFS [RR: 1.0; 95% CI: 0.92-1.08, P = .929] and OS [RR: 0.9; 95% CI: 0.92-1.01; P = .148] at 3-4 years follow-up. The risk of secondary primary malignancy (SPM) was also similar between the two groups (RR: 1.2; 95% CI: 0.84-1.92; P = .2). Data on adverse events were limited. CONCLUSION: Our data suggest that, in NDMM patients treated with upfront ASCT, post-transplant consolidation may improve depth of response, but does not add to OS or PFS, compared to lenalidomide maintenance alone. However, data in this context are still immature.

Prevalence of geriatric impairments and frailty categorization among real-world patients with multiple myeloma: a prospective cohort study (MFRAIL).

There is limited knowledge regarding the prevalence of geriatric impairments and frailty among patients with multiple myeloma (MM) in a real-world setting. This study evaluated the distribution of frailty profiles among 116 patients with newly diagnosed or relapsed MM, using four common frailty scales. The proportion of patients classified as frail varied significantly, ranging from 15.5% to 56.9%, due to differences in how frailty was operationalized between each frailty measure. Functional, cognitive, and mobility impairments were common overall and irrespective of performance status. Analyses between frailty and treatment selection (dose reduction and doublet vs. triplet therapy) demonstrated significant differences in non-steroid MM drug dose reductions between frail vs. non-frail patients, as scored by the International Myeloma Working Group (IMWG) Frailty Index and Simplified Frailty Score (p < .05). A standardized approach to frailty assessment that is practical in application, and beneficial in guiding treatment selection and minimizing treatment related toxicity is necessary to provide optimal tailored care.

Belantamab mafodotin, pomalidomide and dexamethasone in refractory multiple myeloma: a phase 1/2 trial.

Due to evolving treatment standards for newly diagnosed multiple myeloma, many patients will be triple-class exposed after initial relapses and have poor survival. Novel therapies and combinations are therefore required to improve outcomes. B cell maturation antigen (BCMA)-targeted biologics have emerged as an important new area of therapeutics for relapsed multiple myeloma. The two-part ALGONQUIN trial evaluated various doses and schedules of the anti-BCMA antibody-drug conjugate belantamab mafodotin plus pomalidomide and dexamethasone for patients who are lenalidomide refractory and proteosome inhibitor exposed. The primary endpoints, including evaluating dose-limiting toxicities, establishing the recommended Part 2 dose (RP2D) and overall response rate for patients treated at the RP2D, were met. Secondary efficacy endpoints included progression-free survival and overall survival. Patients treated on study (N = 87) had a median of three previous regimens and 55.2% were triple-class refractory. At the RP2D the most common adverse events were decrease in best-corrected visual acuity (71.1%), keratopathy (65.8%), fatigue (57.9%), infection (47.4%; 7.9% grade ≥3), neutropenia (39.5%) and thrombocytopenia (39.5%). For RP2D patients (n = 38), the overall response rate was 85.3%, ≥very good partial response 75.7% and estimated two-year progression-free survival 52.8% (95% confidence interval, 33.9% to 82.4%), at a median follow-up of 13.9 months. The RP2D schedule was associated with manageable antibody-drug conjugate-associated corneal adverse events and improved tolerability without compromising efficacy. Belantamab mafodotin plus pomalidomide and dexamethasone induced durable responses with promising overall survival in relapsed multiple myeloma, the results of which are yet to be confirmed in the phase 3 DREAMM-8 study. ClinicalTrials.gov Identifier: NCT03715478 .

Long-term follow-up of outcomes including progression-free survival 2 in patients with transplant-ineligible multiple myeloma in the real-world practice: A multi-institutional report from the Canadian Myeloma Research Group (CMRG) database.

Multiple myeloma remains an incurable cancer mostly affecting older adults and is characterized by a series of remission inductions and relapses. This study aims to evaluate the outcomes in newly diagnosed transplant-ineligible patients using bortezomib/lenalidomide-based regimens in the Canadian real world as well as their outcomes in the second line. The Canadian Myeloma Research Group Database (CMRG-DB) is a national database with input from multiple Canadian Centres with now up to 8000 patients entered. A total of 1980 transplant ineligible patients were identified in the CMRG-DB between the years of 2007-2021. The four most commonly used induction regimens are bortezomib/melphalan/prednisone (VMP) (23%), cyclophosphamide/bortezomib/dexamethasone (CyBorD) (47%), lenalidomide/dexamethasone (Rd) (24%), and bortezomib/lenalidomide/dexamethasone (VRd) (6%). After a median follow-up of 30.46 months (0.89-168.42), the median progression-free survival (mPFS) and median overall survival (mOS) of each cohort are 23.5, 22.9, 34.0 months, and not reached (NR) and 64.1, 51.1, 61.5 months, and NR respectively. At the time of data cut-off, 1128 patients had gone on to second-line therapy. The mPFS2 based on first-line therapy, VMP, CyBorD, Rd, and VRd is 53.3, 48.4, 62.7 months, and NR respectively. The most common second-line regimens are Rd (47.4%), DRd (12.9%), CyBorD (10.3%), and RVd (8.9%) with a mPFS and a mOS of 17.0, 31.1, 15.4, and 14.0 months and 34.7, NR, 47.6, 33.4 months, respectively. This study represents the real-world outcomes in newly diagnosed transplant-ineligible myeloma patients in Canada. The spectra of therapy presented here reflect the regimens still widely used around the world. While this is sure to change with anti-CD38 monoclonal antibodies now reflecting a new standard of care in frontline therapy, this cohort is reflective of the type of multiple myeloma patient currently experiencing relapse in the real-world setting.

Tandem Autologous Stem Cell Transplantation Does Not Benefit High-Risk Myeloma Patients in the Maintenance Era: Real-World Results from The Canadian Myeloma Research Group Database.

In patients with multiple myeloma (MM), the presence of high-risk cytogenetic abnormalities is associated with worse disease control and survival. Autologous stem cell transplant (ASCT) does benefit these patients. Tandem transplantation has been explored as a means to deepen responses and further improve survival however, its role remains controversial. This is particularly true in the era of novel agent induction and post-transplant maintenance therapy. The aim of this study was to use the Canadian Myeloma Research Group database and examine a large cohort of real-world patients comparing the outcomes of tandem versus single ASCT specifically in high-risk patients receiving novel agent-based induction and post-transplant maintenance. The data for this study was derived retrospectively from a comprehensive national-level database of Canadian patients with MM. High-risk cytogenetics was defined as presence of del17p, t(4;14), or t(14;16). Those receiving allogeneic transplant were excluded. Tandem transplantation was defined as a second ASCT performed consecutively without interim relapse or progression after first ASCT. Those with relapse or progressive disease within 3 months of completing a first transplant were excluded. We compared response depth, progression-free, and overall survival (OS) based on single or tandem transplantation procedures. The impact of covariates of interest was also assessed. A total of 381 patients with high-risk cytogenetics were identified. A total of 242 received single and 139 patients received tandem transplants. All received post-transplant maintenance. The most common induction regimen for these patients was cyclophosphamide, bortezomib, and steroids (CyBorD, 87%). Forty-one patients (10.8%) required reinduction prior to first ASCT. The best overall responses at any time were 98.3% (90.5% ≥ very good partial response [VGPR]) and 98.6% (89.9% ≥ VGPR) in the single and tandem ASCT groups, respectively. Survival outcomes were similar with the median progression-free survival for single or tandem ASCT of 35.2 and 35.3 months (P = .88) and the median OS were 92.6 and 88.9 months, respectively (P = .72). No statistically significant differences were seen based on type of cytogenetic abnormality or type of maintenance. This was confirmed on multivariate analysis. In the real-world setting, tandem ASCT does not improve outcomes for MM patients with high-risk cytogenetics. This may be driven by the use of effective pre- and post-ASCT therapies. The development of more potent induction and consolidation along with current nearly ubiquitous continuous maintenance therapies until disease progression does not support the use of a second high-dose procedure.

Serologic Response to Vaccine for COVID-19 in Patients with Hematologic Malignancy: A Prospective Cohort Study.

BACKGROUND: Patients with hematological cancers have increased COVID-19 morbidity and mortality, and these patients show attenuated vaccine responses. This study aimed to characterize the longitudinal humoral immune responses to COVID-19 vaccination in patients with hematological malignancies. PATIENTS AND METHODS: We conducted a prospective cohort study, collecting samples from March 2021 to July 2022, from patients seen at a cancer treatment center in London, Ontario, Canada, who met the following eligibility criteria: age ≥18 years, diagnosed with a hematological malignancy, recipient of a COVID-19 vaccine during the study period, and able to provide informed consent. RESULTS: Median anti-S titers (MST) were 0.0, 64.0, and 680.5 U/mL following first (V1), second (V2), and third (V3) vaccine doses, respectively. Patients with lymphoid malignancies' response to vaccination was attenuated compared to myeloid malignancy patients after V2 and V3 (P < .001, P < .01). Active treatment was associated with lower antibody titers (MST 10) compared to treatment 12-24 months (MST 465, P = .04367) and >24 months (MST 1660.5, P = .0025) prior to vaccination. V3 significantly increased antibody titers compared to V2 for patients less than 3 months from treatment. Increasing age was associated with smaller antibody response following V2 (P < .05), but not following V3. Patients receiving anti-CD20 therapy did not demonstrate increased antibody titer levels after V3 (V2 MST 0, V3 MST 0; P > .05). CONCLUSION: We report an attenuated serologic response to COVID-19 vaccination in our study population of patients with hematological malignancy. The immune response to vaccination was affected by patient age, diagnosis, treatment, and timing of treatment exposure.

Development of a clinical prediction rule for risk stratification of recurrent venous thromboembolism in patients with cancer-associated venous thromboembolism.

BACKGROUND: Long-term low-molecular-weight heparin (LMWH) is the current standard for treatment of venous thromboembolism (VTE) in cancer patients. Whether treatment strategies should vary according to individual risk of VTE recurrence remains unknown. We performed a retrospective cohort study and a validation study in patients with cancer-associated VTE to derive a clinical prediction rule that stratifies VTE recurrence risk. METHODS AND RESULTS: The cohort study of 543 patients determined the model with the best classification performance included 4 independent predictors (sex, primary tumor site, stage, and prior VTE) with 100% sensitivity, a wide separation of recurrence rates, 98.1% negative predictive value, and a negative likelihood ratio of 0.16. In this model, the score sum ranged between -3 and 3 score points. Patients with a score ≤ 0 had low risk (≤ 4.5%) for recurrence and patients with a score >1 had a high risk (≥ 19%) for VTE recurrence. Subsequently, we applied and validated the rule in an independent set of 819 patients from 2 randomized, controlled trials comparing low-molecular-weight heparin to coumarin treatment in cancer patients. CONCLUSIONS: By identifying VTE recurrence risk in cancer patients with VTE, we may be able to tailor treatment, improving clinical outcomes while minimizing costs.

First Line Treatment of Newly Diagnosed Transplant Ineligible Multiple Myeloma: Recommendations from the Canadian Myeloma Research Group Consensus Guideline Consortium.

Although the availability of effective novel treatments has positively impacted the quality of life and survival of newly diagnosed multiple myeloma (MM) patients, benefits in the transplant ineligible MM population may be limited by functional/frailty status. The Canadian Myeloma Research Group Consensus Guideline Consortium proposes consensus recommendations for the first-line treatment of transplant ineligible MM. To address the needs of physicians and people diagnosed with MM, this document further focuses on eligibility for transplant, frailty assessment, management of adverse events, assessment of treatment response, and monitoring for disease relapse. The Canadian Myeloma Research Group Consensus Guideline Consortium will periodically review the recommendations herein and update as necessary.

Real-world data on lenalidomide dosing and outcomes in patients newly diagnosed with multiple myeloma: Results from the Canadian Myeloma Research Group Database.

Using the Canadian Myeloma Research Group Database, a retrospective study of 167 newly diagnosed, transplant-ineligible patients with multiple myeloma (MM) that received lenalidomide-dexamethasone as front-line treatment was conducted to understand the impact of lenalidomide dosing. Starting dose modifications were common, 42% of patients started on lenalidomide <25 mg with normal renal function. During treatment course, 35% of patients required further dose reduction. Dose reductions in the first year did not have an impact on progression free survival or overall survival. Further studies need to be conducted to understand the impact of dosing strategies of anti-MM agents in the real world.

Redefining attrition in multiple myeloma (MM): a Canadian Myeloma Research Group (CMRG) analysis.

While most patients diagnosed with multiple myeloma (MM) receive initial therapy, reported attrition rates are high. Understanding attrition rates and characteristics of patients not receiving subsequent therapy is useful for MM stakeholders. We performed an analysis of attrition rates in a large disease-specific database of patients with newly diagnosed MM who received at least one line of therapy between Jan 1/10-Dec 31/20. Attrition was defined as failure to receive a subsequent line of therapy despite progression of MM or due to death. A total of 5548 patients were identified, 3111 autologous stem cell transplant (ASCT) patients and 2437 non-ASCT. In the ASCT cohort, the attrition rate was 7% after line 1, 12% after line 2, and 23% after line 3. In non-ASCT patients, the attrition rate was 19% after line 1, 26% after line 2, and 40% after line 3. Death was the dominant contributor to attrition across all cohorts, with a minority of patients alive with progressive disease in the absence of further therapy at each line. Multivariable analysis identified older age, shorter time to progression, and inferior response as independent risk factors for attrition. Our data show that attrition rates increase with each line of therapy and are higher in non-ASCT patients but are appreciably lower than previously reported. This study supports a revision of the previous definition of attrition, demonstrating that most patients who do not receive subsequent therapy are either continuing their current therapy and/or are in remission off-treatment rather than being irreversibly lost to attrition.