Gonsalves, Wilson

AbstractHistological transformation in Waldenström macroglobulinemia (WM) is an uncommon complication, with limited data, particularly regarding the impact of MYD88 L265P mutation on transformation. We examined risk factors and outcomes associated with transformation in WM, highlighting the role of MYD88 L265P mutation. Patients with WM seen at Mayo Clinic, Rochester, USA and University Hospital of Reims, France, between 01/01/1996 and December 31, 2017 were included; 50 (4.3%) of 1147 patients transformed to a high‐grade lymphoma, with median time‐to‐transformation of 4.5 (range 0‐21) years in the transformed cohort. The MYD88 L265P mutation status was known in 435/1147 (38%) patients (406 with non‐transformed WM and 29 patients in transformed cohort). On multivariate analysis, MYD88 WT status alone was an independent predictor of transformation (odds ratio, 7[95%CI: 2.1‐23]; P = .003). Additionally, the MYD88 WT status was independently associated with shorter time‐to‐transformation (HR 7.9 [95%CI: 2.3‐27; P = .001]), with a 5‐year transformation rate of 16% for MYD88 WT vs 2.8% with MYD88 L265P mutated patients. Patients with transformation demonstrated a significant increase in risk of death compared to patients who did not transform (HR 5.075; 95%CI: 3.8‐6.8; P < .001). In conclusion, the MYD88 WT status is an independent predictor of transformation and associated with a shorter time‐to‐transformation. Additionally, transformation conferred an inferior overall survival in patients with WM.

AbstractRisk stratification of multiple myeloma (MM) at diagnosis is critical. We examined the ability of hematopoietic indices including mean corpuscular volume (MCV), hemoglobin (Hgb), and platelet (Plt) to predict outcomes. This was a retrospective study of patients treated at Mayo Clinic between January 2004 and April 2018. We incorporated three variables (Hgb < 10 g/dL, Plt < 150 × 109/L, and MCV > 96 fL), assigning a score of 1 to each. We identified 1540 newly diagnosed MM patients, of whom 707 (46%) had a score of 0, 513 (33%) had a score of 1, 260 (17%) had a score of 2, and 60 (4%) had a score of 3. The score risk stratified patients into four groups with differing survivals. The median PFS was 32.3 months for score 0, 24.8 months for score 1, 21.7 months for score 2, and 18.3 months for score 3, for P < .001. The median OS was 80.7 months for score 0, 59.9 months for score 1, 51.7 months for score 2, and 31.3 months for score 3, P < .0001. Predictors of OS on the multivariable analysis were age ≥ 65 (HR, 1.93; P < .0001), R‐ISS stage (1‐2 vs 3) (HR, 0.48; P < .0001), and hematopoietic score (0‐2 vs 3) (HR, 0.51; P = .006). A hematopoietic score can predict survival in newly diagnosed myeloma patients.

SummaryIbrutinib‐related data in Waldenström macroglobulinaemia (WM) remain sparse, particularly outside of trials. We report on 80 patients [previously treated, n = 67 (84%), treatment‐naïve, n = 13 (16%)] with WM, evaluated consecutively at Mayo Clinic, who received ibrutinib off‐study after its approval in 2015 for WM. Overall response rate (ORR) was 91%; major‐response rate (MRR) was 78%. The median time to first response and best response was 2·9 [95% confidence interval (CI): 2–4] and 5·7 (95% CI: 4–12) months, respectively. The median follow‐up was 19 (95% CI: 14–21) months; 18‐month progression‐free survival (PFS) was 82%. The median time on therapy was 12·5 (95% CI: 9·3–16·7) months, and the median duration‐of‐response was 32 (range: 23–32) months. Twenty‐five patients (31%) had discontinued therapy at last follow‐up (68% due to treatment‐related toxicities) and 18% of patients required dose reduction. Fatigue (12%) and atrial‐fibrillation (11%) were common non‐haematological toxicities. IgM rebound occurred in 36% of patients who abruptly discontinued ibrutinib. Following ibrutinib discontinuation, 84% of patients received subsequent treatment, achieving an ORR of 57% and MRR of 50%. The median PFS from commencement of subsequent salvage therapy was 18 months. Ibrutinib therapy, outside of clinical trials, is effective in WM, but is associated with toxicities and challenges, including IgM rebound and a high drug discontinuation rate for reasons other than disease progression.

Summary Improvement in survival in Light chain (AL) amyloidosis has been seen over recent decades, enabling more patients to achieve long‐term survival. Patients with AL amyloidosis who survived ≥10 years from time of diagnosis ( n = 186) were the subject of this study. Ten‐year survivors represented 22% of the total population. These patients were characterized by favourable patient, organ and plasma cell features. Of note, trisomies were less common among 10‐year survivors compared to those who did not survive to 10 years. All‐time best haematological response was complete response in 67%, very good partial response in 30%, partial response in 2% and no response in 1%, with 11% having received a consolidative strategy for inadequate response to first line therapy. The overall organ response rate to first‐line therapy was 76%, which increased to 86% when considering subsequent line(s) of therapy. Forty‐seven percent of the 10‐year survivors did not require a second‐line therapy. The median treatment‐free survival (TFS) among the 10‐year survivors was 10·5 years (interquartile range 7·4‐12·2). On multivariate analysis independent predictors for TFS were the achievement of complete haematological response and lack of cardiac involvement. Long‐term survivors are increasingly seen in AL amyloidosis and present distinct patient, organ and clonal disease features.

AbstractThe role of consolidation post autologous stem cell transplant in light chain amyloidosis is not well defined. We retrospectively identified patients who had light chain amyloidosis and underwent autologous stem cell transplant at the Mayo Clinic. Consolidation was defined as any treatment given after the day 100 evaluation post‐transplant to maintain or deepen the response. We identified 471 patients, of whom 72 (15%) received consolidation. Patients receiving consolidation had more advanced disease (Mayo 2012 stage ≥II in 67% vs 52%, P = .02), and had lower day 100 response rates (very good partial response or better: 35% vs 84%, P < .001). After consolidation, rates of very good partial response improved from 24% to 28%, and rates of complete response improved from 11% to 40%. Patients with less than very good partial response who received consolidation, had better progression‐free survival (median of 22.4 vs 8.8 months, P < .001), and the benefit was greater in those who deepened their response (median of 41 vs 8.8 months, P < .001). In patients with less than very good partial response, there was a trend for better overall survival in patients who responded to consolidation (median of 125.8 vs 74.4 months, P = .07). In patients who achieved very good partial response, or better, at day 100 post autologous stem cell transplant, consolidation did not improve progression‐free or overall survival. Consolidation after autologous stem cell transplant for light chain amyloidosis improves progression‐free survival for patients who achieve less than very good partial response.

Abstract In appropriately selected patients with AL amyloidosis, autologous stem cell transplant (ASCT) is an established treatment modality with excellent outcomes and decreasing transplant related mortality (TRM) over time. We report on 15‐year overall survival (OS) in 159 patients undergoing ASCT from 1996 to 2003, with median follow up of 17.1 years. Day 100 TRM was 13.2% (n = 21). The OS of ≥15 years was observed in 30% (47/159) of patients. Patients surviving ≥15 years were younger (53 vs 56 years, P = .02), less likely to have lambda as the involved light chain (62% vs 78%, P = .03) and were less likely to have heart involvement (32% vs 56%, P = .005). Median OS of patients with heart involvement vs not was 4.0 vs 11.1 years, P = .006 and actuarial 15‐year OS was 23% vs 43%, respectively. A higher proportion of patients with OS ≥15 years received full‐dose melphalan conditioning (81% vs 61%, P = .01), and achieved day 100 complete response (CR) (64% vs 24%, P < .001). Median OS amongst patients who achieved CR vs not was 19.3 vs 5.4 years, P < .001. Heart involvement, receiving full‐dose melphalan and achieving CR remained independent predictors of OS. AL amyloidosis and related complications were the cause of death in 52% of patients overall (1‐5 years post‐transplant: 81%; 5‐10 years: 62% and 10‐15 years: 55%). These results reinforce the key role of ASCT in AL amyloidosis. With improvements in TRM and more options for relapsed disease, we expect the long‐term survival post‐transplant to improve significantly in the future.

AbstractAchievement of a complete response has been associated with improved outcomes in patients with multiple myeloma. Recently, increasing application of minimal residual disease (MRD) assessment has shown that MRD negativity is a powerful prognostic factor for survival outcomes. We wanted to examine the impact of the polyclonal plasma cell (pPC) compartment among patients in complete response (CR) but are MRD positive. This is a retrospective cohort study where 460 myeloma patients were identified who met criteria for CR and had multicolor flow cytometry performed on the bone marrow (BM). Monoclonal and pPCs were estimated during MRD testing. Final outcomes including overall survival (OS) and time to next treatment (TTNT) were compared among the groups. The median OS for the entire cohort was not reached (95% CI; 63 mos, NR) and the median TTNT was 31 months (95% CI; 27,36). Among the MRDneg group, median TTNT was 37.6 months vs 23 months for MRDpos patients (P < .001); the median OS was not reached for either group, but there was a trend toward better survival for MRDneg patients. Among the MRDpos group, median percentage of pPCs was 65% (2.5–98.5), and those with >95% pPCs had a significantly better TTNT (NR vs 23 months; P = .02) and a trend toward better OS. We conclude that achievement of MRD negativity predicts for better response durability and trend toward improved OS and an increased proportion of pPC predicts for better outcomes within those who have residual tumor cells highlighting the importance of marrow normalization.

SummaryThis study evaluated the differences in clinical features of 1077 newly diagnosed AL amyloidosis patients with renal involvement (n = 229, 21%), both cardiac and renal involvement (n = 443, 41%) and cardiac involvement (n = 405, 38%). Significant differences in dFLC (difference in involved and uninvolved light chains) were noted (renal, both, cardiac median: 83, 234 and 349 mg/l, P < 0.001). The proportion of patients with ≥ 10% bone marrow plasma cells (BMPCs) was lowest in renal only patients: 44%, 57%, 64%, respectively, P < 0.001. In a multivariate linear regression model incorporating organ involvement type and BMPCs ≥10%, organ involvement was a significant predictor of dFLC (P < 0.001). Median overall survival (OS) across the three groups was 83 vs. 19 vs. 16 months (P < 0.001) in patients not undergoing transplant and 5‐year OS in patients undergoing transplant was 90% vs. 75% vs. 64% (P = 0.007), respectively. In conclusion, renal involvement alone or renal + cardiac involvement in AL amyloidosis is associated with lower circulating light chain burden, which cannot be fully explained by BMPC burden alone. Increased sensitivity of the kidney to light chains, given significant interactions with the renal tubular system and secretion of modified light chain products may play a role in pathogenesis of renal AL amyloidosis and warrants further investigation.