Rationale, application and clinical qualification for NT-proBNP as a surrogate end point in pivotal clinical trials in patients with AL amyloidosis.

Amyloid light-chain (LC) amyloidosis (AL amyloidosis) is a rare and fatal disease for which there are no approved therapies. In patients with AL amyloidosis, LC aggregates progressively accumulate in organs, resulting in organ failure that is particularly lethal when the heart is involved. A significant obstacle in the development of treatments for patients with AL amyloidosis, as well as for those with any disease that is rare, severe and heterogeneous, has been satisfying traditional clinical trial end points (for example, overall survival or progression-free survival). It is for this reason that many organizations, including the United States Food and Drug Administration through its Safety and Innovation Act Accelerated Approval pathway, have recognized the need for biomarkers as surrogate end points. The international AL amyloidosis expert community is in agreement that the N-terminal fragment of the pro-brain natriuretic peptide (NT-proBNP) is analytically validated and clinically qualified as a biomarker for use as a surrogate end point for survival in patients with AL amyloidosis. Underlying this consensus is the demonstration that NT-proBNP is an indicator of cardiac response in all interventional studies in which it has been assessed, despite differences in patient population, treatment type and treatment schedule. Furthermore, NT-proBNP expression is directly modulated by amyloidogenic LC-elicited signal transduction pathways in cardiomyocytes. The use of NT-proBNP will greatly facilitate the development of targeted therapies for AL amyloidosis. Here, we review the data supporting the use of NT-proBNP, a biomarker that is analytically validated, clinically qualified, directly modulated by LC and universally accepted by AL amyloidosis specialists, as a surrogate end point for survival.

Effect of severe hypoalbuminemia on toxicity of high-dose melphalan and autologous stem cell transplantation in patients with AL amyloidosis.

High-dose melphalan with stem cell transplantation (HDM/SCT) extends survival and induces hematologic and clinical responses in patients with light chain (AL) amyloidosis. Eighty percent of melphalan is bound to plasma proteins (60% albumin-bound). We hypothesized that patients with profound hypoalbuminemia have a greater free melphalan fraction and more toxicity. Patients with AL amyloidosis treated with HDM/SCT between 2011 and 2014 with severe hypoalbuminemia (SH), defined as serum albumin ⩽2 g/dL were studied retrospectively. Sixteen patients with SH were identified. Forty-one patients without severe hypoalbuminemia (WSH) treated between 2011 and 2012 served as control. The incidence of acute renal failure requiring hemodialysis was 25% among patients with SH, compared with 5% among patients WSH (P=0.05). Not all patients who needed dialysis required it long term; 6.25% for SH and 2.44% for WSH (P=0.49). The rates of grade 3 or 4 febrile neutropenia and gastrointestinal toxicities were not significantly different between the groups. Engraftment kinetics were similar for both groups. Grade 4 renal toxicity and grade 3 lightheadedness were more frequent in patients with SH undergoing HDM/SCT for AL amyloidosis. Further studies into the mechanism of increased renal toxicity in patients with SH are warranted.

Safety and efficacy of high-dose melphalan and auto-SCT in patients with AL amyloidosis and cardiac involvement.

In Ig light chain (AL) amyloidosis, cardiac involvement is associated with worse prognosis and increased treatment-related complications. In this retrospective cohort study, we assessed survival, hematologic and cardiac responses to high-dose melphalan and auto-SCT (HDM/SCT) in patients with AL amyloidosis and cardiac involvement, stratified by cardiac biomarkers brain natriuretic peptide and Troponin I, analogous to the Mayo cardiac staging. Forty-seven patients underwent HDM/SCT based upon functional measures; six patients had modified cardiac stage I disease, seventeen had modified cardiac stage II disease and twenty-four had modified cardiac stage III disease. Treatment-related mortality was 4% for all patients and 8% for patients with stage III disease. Three-year survival was 88% and EFS was 47%; these did not differ by stage. By intention-to-treat analysis, 27% of patients achieved a hematologic complete response and 32% a very good partial response, of whom 70 and 45%, respectively, have not required additional therapy at 36 months. Cardiac response was achieved in 53% of patients. We conclude that with appropriate patient selection and a risk-adapted treatment approach, HDM/SCT is safe and effective in patients with AL amyloidosis and cardiac involvement.

Modified high-dose melphalan and autologous SCT for AL amyloidosis or high-risk myeloma: analysis of SWOG trial S0115.

We designed a trial using two sequential cycles of modified high-dose melphalan at 100 mg/m(2) and autologous SCT (mHDM/SCT) in AL amyloidosis (light-chain amyloidosis, AL), AL with myeloma (ALM) and host-based high-risk myeloma (hM) patients through SWOG-0115. The primary objective was to evaluate OS. From 2004 to 2010, 93 eligible patients were enrolled at 17 centers in the United States (59 with AL, 9 with ALM and 25 with hM). The median OS for patients with AL and ALM was 68 months and 47 months, respectively, and has not been reached for patients with hM. The median PFS for patients with AL and ALM was 38 months and 16 months, respectively, and has not been reached for patients with hM. The treatment-related mortality (TRM) was 12% (11/93) and was observed only in patients with AL after SCT. Grade 3 and higher non-hematologic adverse events were experienced by 81%, 67% and 57% of patients with AL, ALM and hM, respectively, during the first and second HDM/SCT. This experience demonstrates that with careful selection of patients and use of mHDM for SCT in patients with AL, ALM and hM, even in the setting of a multicenter study, OS can be improved with acceptable TRM and morbidity.

Microbiologically documented infections in patients undergoing high-dose melphalan and autologous stem cell transplantation for the treatment of light chain amyloidosis.

BACKGROUND: Immunoglobulin light chain (AL) amyloidosis can be treated with high-dose melphalan and autologous stem cell transplantation (HDM/SCT). Risk factors for infections may include hyposplenism, hypogammaglobulinemia, treatment-related neutropenia, melphalan-induced mucositis, and nosocomial exposures. METHODS AND DESIGN: A review of 493 patients with AL amyloidosis undergoing treatment with HDM/SCT from August 1994 to August 2009 was performed. The objectives were to determine the rate and types of infections following HDM/SCT, to identify factors associated with microbiologically documented infections, and to assess the contribution of infections to all-cause treatment-related mortality (TRM; defined as deaths within 100 days of SCT). RESULTS: Microbiologically documented infections after HDM/SCT occurred in 24% (n = 119) of patients. TRM was 10% (n = 48) overall, and 21% (n = 25) in patients who had a documented infection. Thus, the relative risk of TRM in a patient with a documented infection was 3.42 (95% confidence interval [CI] 2.02-5.79). Infections were caused by gram-positive bacteria in 51%, anaerobic bacteria in 16%, gram-negative bacteria in 13%, and fungi in 9% of cases. Serum creatinine >2 mg/dL was associated with increased risk of post-SCT infection (38% vs. 21%, P = 0.0007) with an odds ratio of 2.27 (95% CI 1.40-3.68). No significant association for infection was found for age, gender, cardiac involvement, prior steroid therapy, dose of melphalan, multiorgan involvement, days to neutrophil engraftment, or dose of CD34 +  cells infused. CONCLUSION: Serum creatinine >2 mg/dL is a risk factor for infections in patients with AL amyloidosis undergoing HDM/SCT. The relative risk of TRM in a patient with a documented infection was increased >3-fold. A broad spectrum of infections, similar to that in other SCT patients, is seen in this population in the early post-SCT period.

Consensus guidelines for the conduct and reporting of clinical trials in systemic light-chain amyloidosis.

This manuscript summarizes the recommendations that emerged from the first Roundtable on Clinical Research in Immunoglobulin Light-chain Amyloidosis (AL), a meeting sponsored by the Amyloidosis Foundation (Clarkston, MI, USA) to develop a consensus of experts on a modern framework for clinical trial design and drug development in AL. Recent diagnostic and technical advances in AL, and updated consensus guidelines for assessing hematologic and organ responses, enable us to define study populations, appropriate end points, and other criteria for all phases of clinical research. This manuscript provides a framework for the design and conduct of systematic collaborative clinical research in AL to encourage more rapid testing of therapies and to expedite new drug development and approval.

Bortezomib in a phase 1 trial for patients with relapsed AL amyloidosis: cardiac responses and overall effects.

BACKGROUND: Bortezomib is approved for the treatment of multiple myeloma and a role has been suggested in the treatment of systemic AL amyloidosis (AL). METHODS: In this phase 1 dose-escalation portion of the first prospective study of single-agent bortezomib in AL, 31 patients with relapsed disease, including 14 (45%) with cardiac involvement, received bortezomib in seven dose cohorts on once-weekly (0.7, 1.0, 1.3, 1.6 mg/m(2)) and twice-weekly (0.7, 1.0, 1.3 mg/m(2)) schedules. Electrocardiographic, Holter and echocardiographic studies were evaluated in all patients to determine safety and response. RESULTS: During therapy (median treatment period 210 days), no patient developed significant ventricular or supraventricular rhythm disturbance on 24-h Holter monitoring; however, no patient satisfied study criteria for cardiac response using echocardiographic assessment or New York Heart Association classification. Seven patients (23%) had a ≥ 10% fall in left ventricular ejection fraction, but only one met criteria for cardiac deterioration. The predominant cardiac adverse events were peripheral edema (23%), orthostatic hypotension (13%) and hypotension (10%). Two patients developed grade 3 congestive heart failure, which resolved following treatment interruption. In this Phase 1 portion, the maximum tolerated dose of bortezomib on either schedule was not reached. Hematologic responses occurred in 14 patients (45%), including seven (23%) complete responses. In non-responders mean left ventricular wall thickness increased during the course of treatment. CONCLUSION: AL is frequently rapidly progressive; in these patients who had relapsed or progressed following previous conventional therapies, these results suggest that bortezomib may slow the progression of cardiac amyloid with limited toxicity.

A second course of high-dose melphalan and auto-SCT for the treatment of relapsed AL amyloidosis.

High-dose melphalan and auto-SCT (HDM/SCT) induces hematological complete responses (HCRs) in 40% of patients with immunoglobulin light chain (AL) amyloidosis. However, relapses occur in 8% of patients who initially achieve HCR. We conducted a study to explore the feasibility and efficacy of a second HDM/SCT in this setting. Eleven patients were enrolled. Five patients underwent repeat stem cell mobilization with G-CSF; the others had stem cells cryopreserved from the first mobilization. Six patients received 200 mg/m(2) HDM; five patients received modified HDM at 140 mg/m(2). Engraftment occurred at a median of 10 days for neutrophils and 12 days for platelets. There was no treatment-related mortality or death within the first year, but significant grade III/IV non-hematological toxicities occurred. In all, 4 of 11 patients (36%) achieved HCR at 1 year. Two of these patients are in continuous remission at 3 and 6 years; the other two relapsed at 2 and 3 years. Of the four patients who achieved partial hematological response at 1 year, three have relapsed at a median of 3 years. Three patients died of progressive disease at 1-2 years. In conclusion, one-third of patients with AL amyloidosis who relapse after HDM/SCT can achieve HCR with a second SCT.

Febrile reactions occurring with second cycle of high-dose melphalan and SCT in patients with AL amyloidosis: a 'melphalan recall' reaction.

Aggressive treatment with high-dose i.v. melphalan followed by auto-SCT (HDM/SCT) is effective in inducing hematological and clinical remissions, and in extending survival in AL amyloidosis. Tandem cycles of HDM/SCT have been shown to increase hematologic complete response rates in patients with AL amyloidosis. Between April 1994 and July 2008, 57 patients with AL amyloidosis at the Boston University Medical Center were treated with a second cycle of HDM/SCT after failing to achieve a complete response after a first transplantation. A total of 11 of 57 patients (19%) treated with tandem transplantation developed high fever 12-24 h after melphalan administration. The average peak temperature was 39.1 degrees C. Other clinical features include hypotension, acute renal failure and skin rash. No infectious etiology was identified. One of the patients had serum available for measurement of cytokines before, during and after the febrile reaction. The concentration of several pro-inflammatory cytokines, including IL-6 and TNFalpha, increased significantly, showing a clear physiological response correlating with the clinical findings. We conclude that an unusual cytokine-mediated febrile reaction can occur in patients with AL amyloidosis exposed to a second cycle of high-dose melphalan, which we have termed a 'melphalan recall' reaction.

Tandem cycles of high-dose melphalan and autologous stem cell transplantation increases the response rate in AL amyloidosis.

Clinical outcomes of patients with AL amyloidosis treated with high-dose melphalan and stem cell transplantation (HDM/SCT) are tightly linked to the achievement of a hematologic complete response (HCR). We conducted a prospective trial to determine whether a second cycle of HDM/SCT could induce HCR in patients in whom the plasma cell dyscrasia persisted following initial treatment with HDM/SCT. Sixty-two patients were enrolled. Nine patients (15%) were removed from the protocol. Of the 53 patients continuing in this study, four died within 100 days of treatment (8%), and 27 (55%) achieved an HCR at 6 months after the first cycle of HDM/SCT. Of the 22 patients who did not achieve an HCR after initial treatment, 17 received a second HDM/SCT, 1 died within 100 days of treatment (6%), while 5 (31%) achieved an HCR. Thus, the HCR rate was 67% (32/48) for surviving patients on study, 60% (32/53) for all patients who received initial cycle of HDM/SCT, and 56% (35/62) by intention-to-treat. The median survival for all patients enrolled on the trial has not yet been reached. Thus, tandem cycles of HDM/SCT can increase the proportion of patients who achieve an HCR.

Clinical and molecular characteristics of patients with non-amyloid light chain deposition disorders, and outcome following treatment with high-dose melphalan and autologous stem cell transplantation.

Light chain deposition disease (LCDD) is caused by a clonal plasma cell disorder in which fragments of monoclonal immunoglobulin light chains form non-fibrillary deposits in various tissues resulting in organ dysfunction. Crystal storing histiocytosis (CSH) is another light chain deposition disorder in which monoclonal light chains form intracytoplasmic crystals. Both are uncommon diseases for which there is limited treatment experience. Between 2003 and 2005, five patients with LCDD and one with CSH were treated at Boston University Medical Center with high-dose melphalan and autologous peripheral blood stem cell transplantation (HDM/SCT). Five of the six patients had predominantly renal involvement, and one patient with LCDD had biopsy-proven deposits in the myocardium. Molecular characterization revealed that the pathologic light chains were kappa in four of the six patients, and sequence analysis revealed unusual germline donor genes and high rates of amino-acid substitutions. One light chain sequence encoded a new potential N-linked glycosylation site, and another showed evidence of antigen selection. All patients are alive and five of the six patients are in complete hematologic remission at a median follow-up of 12 months (range 4-29 months) after HDM/SCT. In our experience, HDM/SCT is a feasible and effective treatment approach for these disorders.

AL amyloidosis associated with B-cell lymphoproliferative disorders: frequency and treatment outcomes.

AL amyloidosis, a systemic disorder characterized by widespread deposition of amyloid fibrils derived from monoclonal Ig light chains in organs and soft tissues, is typically caused by an underlying plasma cell dyscrasia. However, this disease can also be associated rarely with a B-cell lymphoproliferative disorder. In this report, we describe the presentation and clinical course of 16 patients with this association. Although amyloid-related organ involvement in these patients was typical of AL amyloidosis, the patients in this series were on average older and more likely to be female than patients with disease associated with a plasma cell dyscrasia. They were also more likely to have multisystem involvement. Treatment decisions were based primarily on the dominent hematopathologic features of the associated lymphoproliferative disorder. However, high-dose melphalan and stem cell transplantation was the primary therapy in 5 patients, and each of these patients had prolonged survival, ranging from 36 to 102 months.