Kumar, Shaji

Key Points λ Light chain AL amyloidosis is associated with a shorter PFS and OS compared with κ. Light chain type predicts likelihood of organ involvement in AL amyloidosis.

Purpose Autologous stem-cell transplantation (ASCT) has been used in patients with immunoglobulin light chain (AL) amyloidosis for more than two decades. Early experience raised concerns regarding safety with high early-mortality rates. Patients and Methods We report 20 years of experience with ASCT for AL amyloidosis at the Mayo Clinic Rochester. In all, 672 consecutive patients receiving ASCT for AL amyloidosis were divided into three cohorts on the basis of date of transplantation (cohort 1, 1996-2002 [n = 124]; cohort 2, 2003-2009 [n = 302]; and cohort 3, 2010-2016 [n = 246]). Results The median age for the entire cohort was 59 years, with patients in cohort 3 being slightly older than those in the other two cohorts (60 v 58 v 54 years for cohorts 3, 2, and 1, respectively; P < .001). Fewer patients in cohort 3 had more than two organs involved (9% v 18% v 19% for cohorts 3, 2, and 1, respectively; P < .001). More patients received pretransplantation therapy in cohort 3 compared with earlier time periods (49% v 38% v 42% for cohorts 3, 2, and 1, respectively; P = .02). Hematologic response was higher in cohort 3 (84% v 79% v 69% for cohorts 3, 2, and 1, respectively; P = .002). Median overall survival for the entire cohort was 122 months and improved over time (not reached v 120 months v 75 months for cohorts 3, 2, and 1, respectively; P < .001). Treatment-related mortality declined over time (2.4% v 8.6% v 14.5% for cohorts 3, 2, and 1, respectively; P < .001). On multivariable analysis, conditioning dose, Mayo stage 2012, and hematologic response were independent predictors of survival. Conclusion ASCT is a highly effective therapy for AL amyloidosis. The improved survival and markedly reduced treatment-related mortality in eligible patients indicate that this will remain an important first-line option even in the era of treatment approaches that use novel agents.

Autologous stem-cell transplantation (ASCT) remains an integral part of treatment for previously untreated, and may have value in the treatment of relapsed patients with, multiple myeloma (MM). The addition of novel agents like immunomodulators and proteasome inhibitors as induction therapy before and as consolidation/maintenance therapy after ASCT has led to an improvement in complete response (CR) rates, progression-free survival (PFS) and overall survival (OS). With advances in supportive care, older patients and patients with renal insufficiency are now able to safely undergo the procedure. The data concerning the timing of ASCT (early in the disease course or at first relapse), single versus tandem (double) ASCT and the role and duration of consolidation and maintenance therapy post ASCT remain conflicting. This review aims to discuss the evolution of stem-cell transplant over the past 3 decades and its current role in the context of newer, safer and more effective therapeutic agents.

572 Background: Single-center observational studies have established the use of single or tandem SCT to salvage relapsed GCT but randomized trials are lacking. We analyzed outcomes and prognostic factors in 2,395 male SCT recipients for relapsed GCT between 1990 and 2015. Methods: Recipients of single or tandem SCT reported to the Center for International Blood and Marrow Transplant Research were identified. Outcomes were compared by SCT year: 1990-94 (N = 288), 1995-99 (N = 351), 2000-04 (N = 376), 2005-09 (N = 509) and 2010-15 (N = 871). A recent subset (n = 267, 2000-2015) with detailed disease- and transplant-related data was further analyzed with a multivariate (MVA) Cox proportional hazards model. Results: Median age at SCT was 31 (11-76) years and 49% received SCT within 12 months of diagnosis consistent with early relapse/primary refractory GCT. 26% had primary extragonadal GCT; 1,167 (49%) had intent to tandem transplant (TT). The median follow up was 51 (3-313) months. Day 100 non-relapse mortality was statistically similar at 8% in 1990-94 (vs. 4% in 2010-15) but 3-year progression-free survival (PFS) improved from 24 (18-31)% in 1990-94 to 47 (43-50)% in 2010-15 (p < 0.0001) and 3-year survival (OS) from 35 (29-40)% to 54 (50-57)% in 2010-15 (p < 0.0001). Compared with single SCT, TT recipients were younger 31 (16-62) vs 34 (13-76), with lower Hematopoietic Cell Transplantation-Comorbidity Index, more likely to undergo SCT after 1 line of chemotherapy (28% vs 9%), and within 1 year of diagnosis (51% vs 38%). TT was preferred over single SCT over time (48% of SCT were TT in 2000-04 vs. 81% in 2010-15). In MVA, non-seminoma histology, residual tumor at SCT, receipt of > 1 line of pre-SCT chemotherapy and single SCT (vs. TT), were associated with worse PFS and OS. Year of SCT was not significant when adjusted for these covariates. Conclusions: In this large longitudinal cohort, improvements in PFS and OS were observed in recent years. SCT earlier in disease course and tandem SCT were associated with superior outcomes. These data involving a large cohort reported from 225 centers confirm specialized centers’ date in a real-world setting.

The production of the oncometabolite 2-hydroxyglutarate (2-HG) has been associated with c-MYC overexpression. c-MYC also regulates glutamine metabolism and drives progression of asymptomatic precursor plasma cell (PC) malignancies to symptomatic multiple myeloma (MM). However, the presence of 2-HG and its clinical significance in PC malignancies is unknown. By performing 13 C stable isotope resolved metabolomics (SIRM) using U[ 13 C 6 ]Glucose and U[ 13 C 5 ]Glutamine in human myeloma cell lines (HMCLs), we show that 2-HG is produced in clonal PCs and is derived predominantly from glutamine anaplerosis into the TCA cycle. Furthermore, the 13 C SIRM studies in HMCLs also demonstrate that glutamine is preferentially utilized by the TCA cycle compared with glucose. Finally, measuring the levels of 2-HG in the BM supernatant and peripheral blood plasma from patients with precursor PC malignancies such as smoldering MM (SMM) demonstrates that relatively elevated levels of 2-HG are associated with higher levels of c-MYC expression in the BM clonal PCs and with a subsequent shorter time to progression (TTP) to MM. Thus, measuring 2-HG levels in BM supernatant or peripheral blood plasma of SMM patients offers potential early identification of those patients at high risk of progression to MM, who could benefit from early therapeutic intervention.

AbstractWaldenström macroglobulinemia (WM) is an immunoglobulin M‐associated lymphoma, with majority of cases demonstrating MYD88 locus alteration, most commonly, MYD88L265P. Owing to low prevalence of the wild‐type (WT) MYD88 genotype in WM, clinically relevant data in this patient population are sparse, with one study showing nearly a 10‐fold increased risk of mortality in this subgroup compared to patients with MYD88L265P mutation. We studied a large cohort of patients with MYD88L265P and MYD88WT WM, evaluated at Mayo Clinic, Rochester, between 1995 and 2016, to specifically assess the impact of these genotypes on clinical course. Of 557 patients, MYD88L265P mutation status, as determined by allele‐specific polymerase chain reaction, was known in 219, and 174 (79%) of those exhibited MYD88L265P, 157 of 174 patients had active disease. Of 45 (21%) patients with MYD88WT genotype, 44 had active disease. The estimated median follow‐up was 7.0 years; median overall survival was 10.2 years (95% CI: 8.4‐16.5) for MYD88L265P versus 13.9 years (95% CI: 6.4‐29.3) for the MYD88WT (P = 0.86). The time‐to‐next therapy from frontline treatment and the presenting features were similar in the two patient populations. For patients with smoldering WM at diagnosis, the median time‐to‐progression to active disease was 2.8 years (95% CI: 2.2‐3.8) in the MYD88L265P cohort and 1.9 years (95% CI: 0.7‐3.1) in the MYD88WT cohort (P = 0.21). The frequency of transformation to high‐grade lymphoma, or the development of therapy‐elated myelodysplastic syndrome was higher in the MYD88WT cohort (16% versus 4% in the MYD88L265P, P = 0.009). In conclusion, MYD88L265P mutation does not appear to be a determinant of outcome, and its presence may not be a disease‐defining feature in WM. Our findings warrant external validation, preferably through prospective studies.