Safety and Efficacy of Propylene Glycol-Free Melphalan in Patients with AL Amyloidosis Undergoing Autologous Stem Cell Transplantation: Results of a Phase II Study.

Patients with systemic light chain (AL) amyloidosis undergoing treatment with high-dose melphalan and autologous stem cell transplantation (HDM/SCT) may develop renal and cardiac toxicities potentially exacerbated by the co-solvent propylene glycol in conventional melphalan formulations. We investigated the safety and efficacy of propylene glycol-free melphalan (PGF-Mel) during HDM/SCT in patients with AL amyloidosis (ClinicalTrials.gov identifier NCT02994784). The primary objective of this phase II, open-label study was evaluation for renal dysfunction, new cardiac arrhythmias, and postural hypotension related to autonomic dysfunction. Secondary objectives included time to neutrophil and platelet engraftment, treatment-related mortality (TRM), overall hematologic response, organ response, and number of peritransplantation hospitalizations. Twenty-eight patients with AL amyloidosis enrolled, of whom 27 underwent HDM/SCT. PGF-Mel at 140 to 200 mg/m2 was administered i.v. in 2 equally divided doses. Patients were monitored for up to 30 days after the last administration of PGF-Mel to assess for treatment-related toxicity. Patients were followed for 12 months from the time of treatment with HDM/SCT for evaluation of hematologic and organ responses. Kaplan-Meier analysis was used to estimate progression-free survival. Two patients (7%) developed renal dysfunction, 5 (19%) experienced new cardiac arrhythmias, and 3 (11%) developed orthostatic hypotension. All patients achieved neutrophil and platelet engraftment, at a median of 10 days and 17 days post-HDM/SCT, respectively. TRM on day +100 was 0%. Peritransplantation hospitalization was required for 23 patients (85%). The most common nonhematologic adverse events were diarrhea (93%), fatigue (82%), and nausea (74%). At 6 months post-HDM/SCT, hematologic complete response or very good partial response occurred in 66% of the patients. At 12 months post-HDM/SCT, renal response occurred in 12 of 23 (52%) patients with renal involvement, and cardiac response occurred in 3 of 11 (27%) patients with evaluable cardiac involvement. Our data indicate that PGF-Mel is safe and efficacious as a high-dose conditioning regimen for autologous SCT in patients with AL amyloidosis.

Modified High-Dose versus High-Dose Melphalan Conditioning in Older Patients Undergoing Autologous Stem Cell Transplantation for Immunoglobulin Light Chain Amyloidosis.

High-dose melphalan and autologous stem cell transplantation (HDM/SCT) induces deep hematologic responses (HR) in patients with newly diagnosed systemic immunoglobulin light-chain (AL) amyloidosis. Modifying melphalan conditioning dose (mHDM <140 mg/m2) is considered in older patients because of concerns regarding tolerability. Age does not predict frailty, and dose modification could compromise responses in an era where effective non-transplant regimens are available. We analyzed 43 patients ≥ 65 years with AL amyloidosis who underwent SCT at Boston University Amyloidosis Center between 2011 and 2020. Median age was 66 years (range 65-68) versus 69 years (range 65-76) in the HDM and mHDM groups, respectively. HR of ≥ very good partial response at 12 months was 66.7% versus 42.3% for patients treated with HDM versus mHDM. Median progression-free survival (PFS) from day 0 of SCT was not reached versus 12.0 months (P =.13); grade ≥ 3 non-hematologic transplant-related toxicities occurred in 87.5% versus 76.9%; and transplant-related mortality was 0% versus 2.3% in the HDM versus mHDM group, respectively. In carefully selected older patients with AL amyloidosis, HDM is well tolerated. Use of mHDM results in reduced HR and PFS; an important consideration with the advent of highly effective non-transplant therapies.

Comparing measures of hematologic response after high-dose melphalan and stem cell transplantation in AL amyloidosis.

Hematologic complete response (hemCR) in AL amyloidosis requires absence of monoclonal protein by immunofixation electrophoreses (IFE) and normal serum free light chain ratio (FLCR). Recent literature suggests that an involved free light chain (iFLC) <20 mg/L or difference in free light chains (dFLC) <10 mg/L may more accurately predict outcomes after treatment. We evaluated overall survival in 340 patients treated with high-dose melphalan and stem cell transplantation (SCT). Of 305 patients evaluable 6 months after SCT, 90 (30%) achieved hemCR, 132 (43%) dFLC <10 mg/L, 118 (39%) iFLC <20 mg/L, and 176 (58%) normal FLCR. Of 215 patients without hemCR, 65 (30%) had dFLC <10 mg/L and 86 (40%) had normal FLCR. Overall survival (OS) in those achieving dFLC <10 mg/L or normal FLCR without hemCR was inferior to those achieving hemCR (p = 0.013 and p = 0.001). OS was not significantly different in patients achieving iFLC <20 mg/L without hemCR compared with hemCR (p = 0.243). Of those with hemCR, OS was not significantly improved if dFLC <10 mg/L was also achieved (p = 0.852), but OS was improved for those with hemCR who also attained iFLC <20 mg/L (p = 0.009). Multivariate analysis demonstrated absence of monoclonal protein in IFE and iFLC <20 mg/L as independent predictors of survival. Attainment of hemCR remains a treatment goal, although achieving iFLC <20 mg/L may also predict improved OS.

Safety, tolerability, and response rates of daratumumab in relapsed AL amyloidosis: results of a phase 2 study.

Daratumumab, a monoclonal CD38 antibody, is approved in the treatment of myeloma, but its efficacy and safety in light-chain (AL) amyloidosis has not been formally studied. This prospective phase 2 trial of daratumumab monotherapy for the treatment of AL amyloidosis was designed to determine the safety, tolerability, and hematologic and clinical response. Daratumumab 16 mg/kg was administered by IV infusion once weekly for weeks 1 to 8, every 2 weeks for weeks 9 to 24, and every 4 weeks thereafter until progression or unacceptable toxicity, for up to 24 months. Twenty-two patients with previously treated AL amyloidosis were enrolled. The majority of the patients had received high-dose melphalan and stem cell transplantation and/or treatment with a proteasome inhibitor. The median time between prior therapy and trial enrollment was 9 months (range, 1-180 months). No grade 3-4 infusion-related reactions occurred. The most common grade ≥3 adverse events included respiratory infections (n = 4; 18%) and atrial fibrillation (n = 4, 18%). Hematologic complete and very-good-partial response occurred in 86% of patients. The median time to first and best hematologic response was 4 weeks and 3 months, respectively. Renal response occurred in 10 of 15 patients (67%) with renal involvement and cardiac response occurred in 7 of 14 patients (50%) with cardiac involvement. In summary, daratumumab is well tolerated in patients with relapsed AL amyloidosis and leads to rapid and deep hematologic responses and organ responses. This trial was registered at www.clinicaltrials.gov as #NCT02841033.

Left Atrial Mechanics Associates With Paroxysmal Atrial Fibrillation in Light-Chain Amyloidosis Following Stem Cell Transplantation.

BACKGROUND: Atrial fibrillation (AF) during high-dose melphalan and autologous stem-cell transplantation (HDM/SCT) for light-chain (AL) amyloidosis confers significant morbidity. Traditional risk factors provide limited prediction for development of paroxysmal AF during this vulnerable period. OBJECTIVES: We sought to assess the association of clinical and echocardiographic parameters, including left atrial (LA) mechanics and development of AF in patients undergoing HDM/SCT therapy. METHODS: Baseline echocardiograms, electrocardiograms, and electronic medical records were retrospectively assessed among patients with AL amyloidosis before HDM/SCT (n = 91). LA function analysis was performed using speckle-tracking echocardiography. RESULTS: In this study, 42 patients (46%) had cardiac involvement; in the peri-transplant period, 12 (13%) developed AF (7 with cardiac involvement). No significant differences in age, sex, cardiac biomarkers, or cardiac risk factors were seen between patients with and without development of AF; one-third of patients with AF peri-transplant had previous AF. Although LA reservoir strain was reduced in patients with development of AF, time to peak strain rate indexed to R-R interval (TPSRI) (p = 0.001) was prolonged in patients with development of AF compared with sinus rhythm patients in the total cohort but also in subgroups with and without cardiac involvement. CONCLUSIONS: TPSRI, a parameter of mechanical dispersion in the early reservoir phase of LA function, is associated with development of AF among patients undergoing HDM/SCT for AL amyloidosis. These findings require validation in larger prospective cohorts.

High-dose melphalan and autologous peripheral blood stem cell transplantation in patients with AL amyloidosis and cardiac defibrillators.

Cardiac deposition of misfolded light chains is the leading cause of morbidity and mortality in patients with immunoglobulin (AL) amyloidosis. Cardiac defibrillators can be used in the management of patients with advanced cardiac amyloidosis, but data concerning the use of these devices in patients undergoing treatment with high-dose melphalan followed by autologous peripheral blood stem cell transplantation (HDM/SCT) is limited. Herein we describe a single-institution experience of HDM/SCT in 15 patients with cardiac defibrillators. During the peri-transplant period, five of these patients (33%) had detectable cardiac arrhythmias and two patients (13%) had implantable cardiac defibrillator (ICD) discharges. Thirteen of the 14 evaluable patients (93%) achieved at least a partial hematologic response. Transplant-related mortality was 6.7% and median overall survival was 40.8 months, with multiple patients achieving an overall survival of >10 years. These data highlight the feasibility of HDM/SCT in patients with an ICD due to advanced cardiac AL amyloidosis, but highlight the need for additional research to appropriately determine which patients will benefit from this aggressive therapy.

Induction Therapy with Bortezomib and Dexamethasone and Conditioning with High-Dose Melphalan and Bortezomib Followed by Autologous Stem Cell Transplantation for Immunoglobulin Light Chain Amyloidosis: Long-Term Follow-Up Analysis.

In immunoglobulin light-chain (AL) amyloidosis, the depth of hematologic response to treatment is associated with improved survival and organ responses. We conducted a clinical trial using bortezomib in induction and in conditioning with melphalan before stem cell transplantation (SCT) for AL amyloidosis. The results of this clinical trial with a median follow-up of 36 months have been reported previously. Here we report the long-term results of this clinical trial with a median follow-up of 77 months. We describe survival, durability of hematologic and organ responses, and relapse rates. Thirty-five patients were enrolled between 2010 and 2013. Hematologic complete response and very good partial response (VGPR) were noted in 100% (27 of 27) of the evaluable patients at 6 months post-SCT. Four patients (15%) had hematologic relapse at a median of 42 months, and 1 patient (3.7%) had organ progression despite maintaining a VGPR at 37 months. The median overall survival and progression-free survival have not yet been reached at the time of this report. Renal and cardiac responses occurred in 65% and 88%, respectively, at 5 years post-SCT. The median time to renal and cardiac response was 12 months and 6 months, respectively. In conclusion, incorporating bortezomib into induction and conditioning yielded durable hematologic responses of AL amyloidosis, with corresponding organ responses and prolonged survival.

Modified High-Dose Melphalan and Autologous Stem Cell Transplantation for Immunoglobulin Light Chain Amyloidosis.

High-dose melphalan and autologous stem cell transplantation (HDM/SCT) have been used in patients with immunoglobulin light chain (AL) amyloidosis for over 2 decades now with durable responses, prolonged survival, and decreasing treatment-related mortality. Historically, patients with poorer baseline functional status, advanced age, renal compromise, and cardiac involvement have been treated with a risk-adapted modified conditioning dose of melphalan (mHDM) of 100 to 140 mg/m2 before SCT. In part because of these baseline characteristics, patients receiving mHDM/SCT have had poorer outcomes compared with patients receiving full-dose melphalan at 200 mg/m2. With the advent of novel therapeutic agents such as proteasome inhibitors, immunomodulatory agents, and monoclonal antibodies for the treatment of AL amyloidosis, it is imperative to understand the long-term effects of mHDM/SCT. Here we report the long-term outcomes of 334 patients with AL amyloidosis treated with mHDM/SCT. Median overall survival was 6.1 years and median event-free survival 4.3 years, with median overall survival reaching 13.4 years for patients who had achieved a hematologic complete response (CR). Overall hematologic response rate was 69%, and treatment-related mortality was 3% after 2010. Thus, mHDM/SCT leads to prolonged survival and favorable outcomes, especially if a hematologic CR is achieved.

Evaluation of a new continuous mononuclear cell collection procedure in a single transplant center cohort enriched for AL amyloidosis patients.

BACKGROUND: The Spectra Optia continuous mononuclear cell (CMNC) program is newly available, and herein validated in a single-center cohort enriched with AL amyloidosis patients to collect a target CD34+ yield of 2.5 × 106 cells/kg within 2 days. METHODS: Consecutive autologous transplant patients in 2016 are included. Patients undergo leukapheresis with Optia CMNC and Spectra v4.7 over a 2-day cycle. Data collection includes collection efficiency, adverse events and engraftment kinetics. RESULTS: 36 leukapheresis procedures on 18 patients are included. The diagnoses are AL amyloidosis (9), myeloma (7), lymphoma (2), and scleroderma (1). Median age is 60; 12 are men. Plerixafor was employed pre-emptively in 6 cycles. Median blood CD34+ on Day 1 of leukapheresis was 46 cells/uL. Median number of blood volumes processed on Day 1 was 3.1. All collection cycles were completed within 2 days; only one in a heavily pretreated lymphoma patient did not reach the target requiring a second mobilization attempt. Mean collection efficiencies were comparable between the two devices. There were 2 adverse events: tubing rupture on the Optia; and one case of hypotension. All 18 patients underwent high-dose chemotherapy: median cell dose infused was 7.7 × 106 CD34+ cells/kg. Median days to neutrophil and platelet engraftment were 10 and 13 respectively. CONCLUSION: The Optia CMNC collection protocol is safe and effective in a small single-center autologous stem cell transplant cohort enriched for high-risk patients with AL amyloidosis and cardiac involvement. Caution is needed for tubing setup because there is less cumulative experience with Optia.

High-Dose Melphalan and Stem Cell Transplantation in Patients on Dialysis Due to Immunoglobulin Light-Chain Amyloidosis and Monoclonal Immunoglobulin Deposition Disease.

The kidney is the most common organ affected by immunoglobulin light-chain (AL) amyloidosis and monoclonal immunoglobulin deposition disease (MIDD), often leading to end-stage renal disease (ESRD). High-dose melphalan and stem cell transplantation (HDM/SCT) is effective for selected patients with AL amyloidosis, with high rates of complete hematologic response and potential for improved organ dysfunction. Data on tolerability and response to HDM/SCT in patients with ESRD due to AL amyloidosis and MIDD are limited. We analyzed data on toxicity, efficacy, and hematologic and renal response of HDM/SCT in 32 patients with AL amyloidosis and 4 patients with MIDD who were dialysis-dependent for ESRD treated at Boston Medical Center between 1994 and 2016. The most common grade 3/4 nonhematologic toxicities were infections (75%), metabolic abnormalities (56%), mucositis (42%), constitutional symptoms (39%), pulmonary complications (39%), and diarrhea (28%). Treatment related mortality (defined as death within 100 days of SCT) occurred in 8% (3 of 36). A complete hematologic response was achieved in 70% of evaluable patients (19 of 27) at 1 year after HDM/SCT. In the entire cohort, median overall survival (OS) after HDM/SCT was 5.8 years; median OS was 1 year for those who did not achieve a complete hematologic response and 8 years for those who did achieve a complete hematologic response. Twelve patients (33%) underwent kidney transplantation after successful treatment with HDM/SCT at a median of 2.4 years after SCT. HDM/SCT is safe and effective in inducing hematologic complete responses and prolonging survival in patients with ESRD from AL amyloidosis and MIDD. Achievement of a durable hematologic response can make these patients possible candidates for renal transplantation.

Induction Therapy with Bortezomib Followed by Bortezomib-High Dose Melphalan and Stem Cell Transplantation for Light Chain Amyloidosis: Results of a Prospective Clinical Trial.

The depth of hematologic response has been shown to correlate with survival and organ responses for patients with light chain (AL) amyloidosis. We conducted a prospective trial of 2 cycles of induction with bortezomib and dexamethasone on a twice a week schedule followed by conditioning with bortezomib and high-dose melphalan (HDM) and autologous stem cell transplantation (SCT). The objectives were hematologic responses, tolerability, and survival. Thirty-five patients were enrolled from 2010 to 2013. Of these, 30 proceeded with SCT, whereas 5 did not because of clinical deterioration during induction (n = 3) or complications after stem cell collection (n = 2). Two patients developed features of an autologous graft-versus-host disease-like syndrome post-SCT, which responded to steroids; no other unusual complications were seen. Treatment-related mortality occurred in 8.5% (3/35). Hematologic responses were achieved by 100% of the 27 assessable patients (63% complete response, 37% very good partial response [VGPR]) who completed the planned treatment. By intention-to-treat, hematologic responses occurred in 77% of patients (49% complete response, 29% VGPR). With a median follow-up of 36 months, the median overall survival and progression-free survival were not reached. In conclusion, incorporating bortezomib into induction and conditioning yielded a high rate of hematologic responses after HDM/SCT in patients with AL amyloidosis.