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

Presence of t(11;14) in AL amyloidosis as a marker of response when treated with a bortezomib-based regimen

The proteasome inhibitor, bortezomib, has become a backbone for the first line treatment of patients with AL amyloidosis who are not eligible for high dose melphalan and stem cell transplantation. The presence of t(11;14), seen in up to 40-60% of patients with AL amyloidosis, may be associated with poorer response when treated with bortezomib based regimens. This remains a critical distinction in light of recent evidence demonstrating favourable responses to BCL-2 inhibition with venetoclax in patients with t(11;14) in multiple myeloma. We report on 135 patients with newly diagnosed AL amyloidosis treated with a bortezomib-based regimen as first line therapy between 2013 and 2017. Treatment outcomes were compared between a cohort of patients with t(11;14) and those without the translocation. Forty-four patients had the presence of t(11;14). Five-year overall survival was 46% for those with t(11;14) and 72% in patients without this translocation (p = .026). The median haematologic event free survival was 17 months for patients with t(11;14) compared to 34 months without (p = .068). Haematologic response of VGPR or better was achieved in 41% of patients with t(11;14) vs 66% without t(11;14) (p = .012). Cardiac and renal responses to first line treatment with bortezomib-based regimens were also higher in patients without t(11;14). In conclusion, patients with AL amyloidosis and the presence of t(11;14) have inferior outcomes with respect to survival, as well as haematologic and organ responses, when treated with bortezomib-based regimens as first line therapy.

The efficacy and safety of bortezomib-based chemotherapy for immunoglobulin light chain amyloidosis: A systematic review and meta-analysis

BACKGROUND

The role of bortezomib in the treatment of immunoglobulin light chain (AL) amyloidosis is not well defined. We performed this meta-analysis to evaluate the efficacy and safety of bortezomib-based regimens in patients with AL amyloidosis who are not eligible for or refuse autologous stem cell transplantation.

METHODS

A systematic search of Medline, Embase, and the Cochrane Library was conducted to identify related studies.

RESULTS

Twenty-four studies with 1238 patients were included. The pooled overall response rate (ORR) and complete hematological response rate (CHR) were 0.72 (95% CI, 0.67-0.77) and 0.35 (95% CI, 0.30-0.40), respectively. Bortezomib significantly improved the outcome of ORR compared to other regimens (RR 1.28, 95% CI, 1.04-1.57, P = .02). Similar results were observed in CHR (RR 1.90, 95% CI, 1.45-2.50, P < .001) and cardiac response (RR 2.03, 95% CI, 1.31-3.13, P = .002), but not in overall survival (HR 0.82, 95% CI, 0.62-1.09, P = .17). In addition, once-weekly bortezomib was associated with improved overall survival compared with twice-weekly bortezomib (HR 0.52, 95% CI, 0.27-0.99, P = .05). Peripheral neuropathy was the most widely reported adverse event. Incorporation of bortezomib into the standard melphalan + dexamethasone setting showed a trend of increased serious adverse events, though this was not statistically significant (RR 1.29, 95% CI, 0.95-1.75, P = .10).

CONCLUSIONS

Current evidence indicates that bortezomib-based regimens might be effective and safe therapies for patients with AL amyloidosis. There is a great need to conduct more well-designed randomized controlled trials to provide high-quality evidence.

The Effect and Safety of Bortezomib in the Treatment of AL Amyloidosis: A Systematic Review and Meta-Analysis

Bortezomib began to be used in the treatment of light chain (AL) amyloidosis in recent years. We performed the first meta-analysis of randomized clinical trials and clinical controlled trials to evaluate the effect and safety of bortezomib treatment for AL amyloidosis. We conducted a search (until July 2016) in electronic databases (PubMed databases and the Cochrane Central Register of Controlled Trials bases from the year 2003). There were 205 records we searched and eight studies was included (n = 617 persons). We demonstrated that bortezomib treatment significantly improved overall response rate (ORR), complete response, a cardiac response rate, 2-year overall survival and the risk of neuropathy and reduced overall mortality compared to controls without bortezomib therapy. From the comparison and subgroup analysis of ORR between bortezomib group and no bortezomib group, the patients with bortezomib had a higher ORR, especially patients pretreated with bortezomib before high-dose melphalan followed by autologous stem cell transplant compared to no pretreatment. In addition, patients with bortezomib in standard dosage had significantly higher ORR. According to our results, bortezomib should be used in AL amyloidosis patients to improve response rate and survival rate and future relevant randomized controlled trials require to be performed.

Newer Therapies for Amyloid Cardiomyopathy

The heart and the kidneys are the most commonly involved organs in systemic amyloidosis. Cardiac involvement is associated with an increased morbidity, treatment intolerance, and poorer overall survival. The most common types of amyloidosis that are associated with cardiac involvement include light chain (AL) amyloidosis and transthyretin (TTR) amyloidosis (both mutant and wild type). The traditional first-line treatment for AL amyloidosis includes alkylator-based chemotherapy or high-dose melphalan followed by autologous stem cell transplantation (ASCT). Novel agents, including proteasome inhibitors, immunomodulators, and monoclonal antibodies, have shown promising activity in both frontline and relapsed settings. Orthotopic heart transplantation (OHT) followed by ASCT has led to superior outcomes compared to OHT alone. Orthotopic liver transplantation (OLT) is the first-line treatment for TTR amyloidosis. However, progression of cardiac amyloidosis after OLT is often noted due to deposition of wild TTR. Combined OLT and OHT also has a role in treatment and leads to superior outcomes in carefully selected candidates. Pharmacologic agents, including diflunisal, tafamidis, small interfering ribonucleic acid, and doxycycline, have shown promising activity in stabilizing TTR from misfolding into fibrils and are being actively investigated. Best supportive care and management of heart failure symptoms with diuretics are a mainstay of treatment in all cardiac amyloidosis subtypes. Robust data on the benefit of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or beta blockers in amyloid cardiomyopathy is lacking.

Cardiovascular complications of multiple myeloma in the elderly

INTRODUCTION

Multiple myeloma is a malignant neoplasm characterized by plasma cell proliferation in blood and bone marrow. Approximately two-thirds of the patients with multiple myeloma are >65 years at the time of diagnosis. Patients in this age group often have co-existing cardiovascular diseases. Areas covered: The presence of multiple myeloma adds to the malady by direct deposition of amyloid protein in the heart or via toxicity of chemotherapeutic agents. Cardiac contractile dysfunction, arrhythmias and thromboembolic disorders are the main issues in the management of elderly patients with multiple myeloma. Expert commentary: Assessment of cardiac risk and functional status requires careful evaluation by history, physical examination and imaging studies such as echocardiography and magnetic resonance imaging. The management of cardiovascular disorders in the presence of multiple myeloma is difficult and poses a challenge for the internist, the oncologist, and the cardiologist alike. This review is an overview of the problem of cardiovascular risk in and management of elderly patients with multiple myeloma.

Prognostic significance of interventricular septal thickness in patients with AL amyloidosis

The major prognostic determinant of immunoglobulin light chain (AL) amyloidosis is cardiac involvement. However, the role of interventricular septal thickness (IVST), which reflects the extent of cardiac involvement, remains unclear. Therefore, we analyzed 77 patients with newly diagnosed AL amyloidosis and evaluated the prognostic role of IVST. Fifty patients (64.9%) had cardiac involvement and 17 patients (22.1%) showed IVST >15mm. Among all patients, the revised Mayo Clinic Stage III-IV and IVST >15mm were independently associated with inferior overall survival (OS) in a multivariable analysis. IVST >15mm was also adversely prognostic for OS in a subgroup of advanced-stage (revised Mayo Clinic stage III-IV) patients in a multivariable analysis (P<0.001). Furthermore, advanced-stage patients with IVST >15mm did not show survival benefit from treatment with bortezomib-based regimens and/or autologous stem-cell transplantation (ASCT). Our study demonstrated that IVST >15mm is adversely prognostic independent of the revised Mayo Clinic staging system in patients with AL amyloidosis. In addition, the degree of IVST might be used as a useful prognostic indicator that can guide the management of patients with AL amyloidosis especially at an advanced stage.

A retrospective analysis of 3954 patients in phase 2/3 trials of bortezomib for the treatment of multiple myeloma: towards providing a benchmark for the cardiac safety profile of proteasome inhibition in multiple myeloma

This retrospective analysis aimed to establish the overall cardiac safety profile of bortezomib using patient-level data from one phase 2 and seven phase 3 studies in previously untreated and relapsed/refractory multiple myeloma (MM). Seven clinically relevant primary [congestive heart failure (CHF), arrhythmias, ischaemic heart disease (IHD), cardiac death] and secondary (hypertension, dyspnoea, oedema) cardiac endpoints were defined based on MedDRA v16.0 preferred terms. 2509 bortezomib-treated patients and 1445 patients in non-bortezomib-based control arms were included. The incidence of grade ≥3 CHF was 1·3-4·0% in studies in relapsed/refractory MM and 1·2-4·7% in previously untreated MM (2·0-7·6% all grades), with no significant differences between bortezomib- and non-bortezomib-based arms in comparative studies. Incidences of arrhythmias (1·3-5·9% grade ≥2; 0·6-4·1% grade ≥3), IHD (1·2-2·9% all grades; 0·4-2·7% grade ≥3) and cardiac death (0-1·4%) were low, with no differences between bortezomib-based and non-bortezomib-based arms. Higher rates of oedema (mostly grade 1/2) were seen in bortezomib-based versus non-bortezomib-based arms in one study and a pooled transplant study analysis. Logistic regression analyses of comparative studies showed no impact on cardiac risk with bortezomib-based versus non-bortezomib-based treatment. Bortezomib-based treatment was associated with low incidences of cardiac events.

Immunoglobulin Light-Chain Amyloidosis: From Basics to New Developments in Diagnosis, Prognosis and Therapy

Immunoglobulin amyloid light-chain (AL) amyloidosis is the most common form of systemic amyloidosis, where the culprit amyloidogenic protein is immunoglobulin light chains produced by marrow clonal plasma cells. AL amyloidosis is an infrequent disease, and since presentation is variable and often nonspecific, diagnosis is often delayed. This results in cumulative organ damage and has a negative prognostic effect. AL amyloidosis can also be challenging on the diagnostic level, especially when demonstration of Congo red-positive tissue is not readily obtained. Since as many as 31 known amyloidogenic proteins have been identified to date, determination of the amyloid type is required. While several typing methods are available, mass spectrometry has become the gold standard for amyloid typing. Upon confirming the diagnosis of amyloidosis, a pursuit for organ involvement is essential, with a focus on heart involvement, even in the absence of suggestive symptoms for involvement, as this has both prognostic and treatment implications. Details regarding initial treatment options, including stem cell transplantation, are provided in this review. AL amyloidosis management requires a multidisciplinary approach with careful patient monitoring, as organ impairment has a major effect on morbidity and treatment tolerability until a response to treatment is achieved and recovery emerges.

Bortezomib-induced acute interstitial nephritis

Acute interstitial nephritis (AIN) is one of the important causes of acute kidney injury (AKI) resulting from inflammatory tubulointerstitial injury induced by medications, infections and systemic diseases. Bortezomib has been increasingly used especially in renal related indications such as multiple myeloma and monoclonal gammopathy of renal significance. Severe allergic reactions from bortezomib treatment including AIN have not been described in the literature. We report a 47-year-old white man who developed biopsy-proven allergic AIN after treatment with bortezomib for his C3 glomerulonephritis. The patient's kidney function improved after treatment with glucocorticoid therapy and discontinuation of bortezomib, but worsened with recurrent AKI episode after re-initiation of bortezomib. His renal function improved after glucocorticoid therapy and discontinuation of bortezomib. To our knowledge, this is the first report of a biopsy-proven AIN from bortezomib.

Phase 1 study of bortezomib in combination with melphalan and dexamethasone in Japanese patients with relapsed AL amyloidosis

We performed a phase 1 study to evaluate the safety and feasibility of bortezomib (BOR) with melphalan and dexamethasone (BMD) in patients with light chain amyloidosis (AL) without severe cardiac failure. Patients received BOR on a twice-weekly schedule (days 1, 4, 8, and 11 of 28-day treatment cycles) at planned doses of 1.0 (dose level 1) and 1.3 (dose level 2) mg/m(2) in combination with melphalan 8 mg/m(2) on days 1-4 and dexamethasone 20 mg on days 1, 2, 4, 5, 8, 9, 11, and 12. Dose-limiting toxicity (DLT) was evaluated at the end of cycle one, and treatment was continued for four cycles. Six patients were enrolled at dose level 1, and one showed DLT (grade 3: herpes zoster). Further 3 patients were enrolled at dose level 2, and none experienced DLT. Thus, the maximum tolerated dose was defined as BOR doses of 1.3 mg/m(2) for the twice-weekly schedule. A total of 32 cycles of BMD therapy were given, and the most common hematologic toxicity was thrombocytopenia (47%). Peripheral neuropathy was the most common non-hematologic toxicity (16%). We demonstrated that BMD is safe and tolerable for Japanese AL patients without severe cardiac damage.

CLINICAL TRIAL REGISTRATION

UMIN000006604.

A phase II trial of lenalidomide, dexamethasone and cyclophosphamide for newly diagnosed patients with systemic immunoglobulin light chain amyloidosis

Immunomodulatory drugs have been shown to be of benefit in relapsed/refractory immunoglobulin light-chain (AL) amyloidosis. We designed a prospective, multicentre phase II trial of lenalidomide, dexamethasone and cyclophosphamide for newly diagnosed patients with AL amyloidosis not eligible for autologous stem-cell transplantation. Twenty-eight patients were included in the study. Cardiac involvement was present in 23 patients; 14 of them had cardiac stage III. The overall haematological response rate was 46%, including complete and very good partial responses in 25% and 18% of patients respectively. Haematological response was mainly associated with absence of cardiac stage III and lower tumour burden. Organ response was observed in 46% of patients. After a median follow-up of 24 months, median progression-free and overall survival have not been reached, both being significantly longer in responders (P < 0·001 and P = 0·001 respectively). Seventeen patients have discontinued treatment, mostly due to amyloid-related death, disease progression or lack of response. Only 14% of the patients discontinued treatment due to therapy-related adverse events. Our results support the efficacy of this regimen, with high quality responses and prolonged survival, as well as its tolerability, in patients with AL amyloidosis not eligible for stem cell transplant and without advanced cardiac involvement (clinicaltrials.gov identifier: NCT01194791).

Translocation t(11;14) Is Associated With Adverse Outcome in Patients With Newly Diagnosed AL Amyloidosis When Treated With Bortezomib-Based Regimens

Purpose

Bortezomib has become a cornerstone in the treatment of AL amyloidosis. In this study, we addressed the prognostic impact of cytogenetic aberrations for bortezomib-treated patients.

Patients and Methods

We analyzed a consecutive series of 101 patients with AL amyloidosis treated with bortezomib-dexamethasone as first-line treatment by interphase fluorescence in situ hybridization (iFISH). Patients were ineligible for high-dose chemotherapy, which would put them at risk for cardiac or renal failure, and thus represented a poor-risk group.

Results

Presence of t(11;14), versus its absence, was associated with inferior hematologic event-free survival (median, 3.4 v 8.8 months, respectively; P = .002), overall survival (median, 8.7 v 40.7 months, respectively; P = .05), and remission rate (≥ very good partial remission; 23% v 47%, respectively; P = .02). In multivariable Cox regression models incorporating established hematologic and clinical risk factors, t(11;14) was an independent adverse prognostic marker for hematologic event-free survival (hazard ratio, 2.94; 95% CI, 1.37 to 6.25; P = .006) and overall survival (hazard ratio, 3.13; 95% CI, 1.16 to 8.33; P = .03), but not for remission (≥ very good partial remission). Markedly, the multiple myeloma high-risk iFISH aberrations t(4;14), t(14;16), del(17p), and gain of 1q21 conferred no adverse prognosis in this bortezomib-dexamethasone–treated group. After backward variable selection, the final multivariable model was validated in a consecutive series of 32 patients treated with bortezomib, dexamethasone, and cyclophosphamide.

Conclusion

iFISH results are important independent prognostic factors in AL amyloidosis. In contrast to our recently published results with melphalan and dexamethasone standard therapy, bortezomib is less beneficial to patients harboring t(11;14), whereas it effectively alleviates the poor prognosis inherent to high-risk aberrations. Given the discrepant response to different treatment modalities, iFISH may help to guide therapeutic choices in these poor-risk patients requiring rapid hematologic response.

Long-term outcomes of primary systemic light chain (AL) amyloidosis in patients treated upfront with bortezomib or lenalidomide and the importance of risk adapted strategies

Bortezomib and lenalidomide are increasingly used in patients with AL amyloidosis, but long term data on their use as primary therapy in AL amyloidosis are lacking while early mortality remains significant. Thus, we analyzed the long term outcomes of 85 consecutive unselected patients, which received primary therapy with bortezomib or lenalidomide and we prospectively evaluated a risk adapted strategy based on bortezomib/dexamethasone to reduce early mortality. Twenty-six patients received full-dose bortezomib/dexamethasone, 36 patients lenalidomide with oral cyclophosphamide and low-dose dexamethasone and 23 patients received bortezomib/dexamethasone at a dose and schedule adjusted to the risk of early death. On intent to treat, 67% of patients achieved a hematologic response (24% hemCRs) and 34% an organ response; both were more frequent with bortezomib. An early death occurred in 20%: in 36% of those treated with full-dose bortezomib/dexamethasone, in 22% of lenalidomide-treated patients but only in 4.5% of patients treated with risk-adapted bortezomib/dexamethasone. Activity of full vs. adjusted dose bortezomib/dexamethasone was similar; twice weekly vs. weekly administration of bortezomib also had similar activity. After a median follow up of 57 months, median survival is 47 months and is similar for patients treated with bortezomib vs. lenalidomide-based regimens. However, risk adjusted-bortezomib/dexamethasone was associated with improved 1-year survival vs. full-dose bortezomib/dexamethasone or lenalidomide-based therapy (81% vs. 56% vs. 53%, respectively). In conclusion, risk-adapted bortezomib/dexamethasone may reduce early mortality and preserve activity while long term follow up indicates that remissions obtained with lenalidomide or bortezomib may be durable, even without consolidation with alkylators.

Targeting the ubiquitin-proteasome system in heart disease: the basis for new therapeutic strategies

SIGNIFICANCE

Novel therapeutic strategies to treat heart failure are greatly needed. The ubiquitin-proteasome system (UPS) affects the structure and function of cardiac cells through targeted degradation of signaling and structural proteins. This review discusses both beneficial and detrimental consequences of modulating the UPS in the heart.

RECENT ADVANCES

Proteasome inhibitors were first used to test the role of the UPS in cardiac disease phenotypes, indicating therapeutic potential. In early cardiac remodeling and pathological hypertrophy with increased proteasome activities, proteasome inhibition prevented or restricted disease progression and contractile dysfunction. Conversely, enhancing proteasome activities by genetic manipulation, pharmacological intervention, or ischemic preconditioning also improved the outcome of cardiomyopathies and infarcted hearts with impaired cardiac and UPS function, which is, at least in part, caused by oxidative damage.

CRITICAL ISSUES

An understanding of the UPS status and the underlying mechanisms for its potential deregulation in cardiac disease is critical for targeted interventions. Several studies indicate that type and stage of cardiac disease influence the dynamics of UPS regulation in a nonlinear and multifactorial manner. Proteasome inhibitors targeting all proteasome complexes are associated with cardiotoxicity in humans. Furthermore, the type and dosage of proteasome inhibitor impact the pathogenesis in nonuniform ways.

FUTURE DIRECTIONS

Systematic analysis and targeting of individual UPS components with established and innovative tools will unravel and discriminate regulatory mechanisms that contribute to and protect against the progression of cardiac disease. Integrating this knowledge in drug design may reduce adverse effects on the heart as observed in patients treated with proteasome inhibitors against noncardiac diseases, especially cancer.

Emerging treatments for amyloidosis

Amyloidosis results from protein misfolding, and ongoing amyloid deposition can ultimately lead to organ failure and death. Historically, this is a group of diseases with limited treatment options and frequently poor prognosis. However, there are now 'targeted' therapeutics emerging in the form of stabilizers of the precursor protein, inhibitors of fibrillogenesis, fibril disruptors, and blockers of protein translation, transcription, and immunotherapy. We review many of these approaches that are currently being assessed in clinical trials.

Bortezomib, melphalan, and prednisolone combination chemotherapy for newly diagnosed light chain (AL) amyloidosis

Bortezomib combination chemotherapy appears to be active in light chain (AL) amyloidosis with high rates of hematologic and organ response. We report a retrospective evaluation of the clinical outcome of treatment with bortezomib, melphalan, and prednisolone (VMP) as first-line chemotherapy in patients with AL amyloidosis who were ineligible for autologous stem cell transplant. Among the 19 patients included in this study, 90% had two or more involved organs and most of the patients had advanced stage AL amyloidosis (84% with 2004 Mayo Stage III and 92% with 2012 Mayo Stage III or IV). Sixteen (84%) patients had a hematologic response, including seven (37%) with complete response, with time to response of 1-3 months. Cardiac and renal responses were observed in 44% and 33% of patients, respectively. Estimated 2-year survival is 39%, and 5 patients (26%) died during therapy. The common grade 3-4 adverse events were thrombocytopenia, diarrhea and pneumonia. A once-weekly bortezomib is more feasible than twice-weekly regimen. Our results suggest that triplet regimen of VMP appears to be an effective regimen in advanced AL amyloidosis ,but benefits in the patients with multi-organ dysfunction remain to be proven.

Proteasome inhibitors in progressive renal diseases

Proteasome (PS) is a sophisticated protein degradation machinery comprising a 20S proteolytic core particle provided with caspase-like, trypsin-like and chymotrypsin-like activities on ubiquitinilated proteins. The products of this selective, complex, controlled and strictly coordinated system play a crucial role in cell cycle progression and apoptosis; activation of transcription factors, cytokines and chemokines; degradation and generation of MHC class I-presented peptides. PS has recently emerged as a promising drug target in cancer therapy, and bortezomib has been approved for refractory multiple myeloma. PS proteolysis is crucial for the degradation of the inhibitory protein IkB of nuclear factor kB (NF-kB), and hence, an interesting field of research has been developed on possible benefits of drugs with anti-PS activity in disease conditions with hyper-expression of NF-kB. PS inhibitors are being adopted in pilot studies in antibody-mediated renal rejection and in AL amyloidosis, with increasing scientific interest in possible applications in lupus, IgA nephropathy, idiopathic nephrotic syndrome and renal fibrosis. The most often used PS inhibitor, bortezomib, has a severe peripheral neurotoxicity, and the search for effective and less toxic PS-targeted drugs is a challenging area also in nephrology.

Long-term follow-up from a phase 1/2 study of single-agent bortezomib in relapsed systemic AL amyloidosis

CAN2007 was a phase 1/2 study of once- and twice-weekly single-agent bortezomib in relapsed primary systemic amyloid light chain amyloidosis (AL) amyloidosis. Seventy patients were treated, including 18 and 34 patients at the maximum planned doses on the once- and twice-weekly schedules. This prespecified final analysis provides mature response and long-term outcomes data after 3-year additional follow-up since the last report. In the once-weekly 1.6 mg/m(2) and twice-weekly 1.3 mg/m(2) bortezomib groups, final hematologic response rates were 68.8% and 66.7%; 80% of patients in each group sustained their response for ≥1 year. One-year progression-free rates were 72.2% and 76.8%. Median overall survival (OS) was 62.1 months and not reached; 4-year OS rates were 75.0% and 63.0%. Low baseline difference in κ/λ free light-chain level was associated with higher hematologic complete response rates and longer OS. At data cutoff, 40 (57%) patients had received subsequent therapy, including 19 (27%) retreated with bortezomib, 11 (58%) of whom achieved complete or partial hematologic responses. Four patients received prolonged bortezomib for between 3.5 and 5.6 years, with no new safety concerns, highlighting the feasibility of long-term therapy. Single-agent bortezomib produced durable hematologic responses and promising long-term OS in relapsed AL amyloidosis. This trial was registered at www.clinicaltrials.gov as #NCT00298766.

Immunoglobulin light chain amyloidosis

Primary light chain amyloidosis is the most common form of systemic amyloidosis and is caused by misfolded light chains that cause proteotoxicity and rapid decline of vital organ function. Early diagnosis is essential in order to deliver effective therapy and prevent irreversible organ damage. Accurate diagnosis requires clinical skills and advanced technologies. The disease can be halted and the function of target organs preserved by the prompt reduction and elimination of the plasma cell clone producing the toxic light chains in the bone marrow. Heart damage is the major determinant of survival, and staging with cardiac biomarkers guides treatment. Two-thirds of patients can benefit from treatment with improved quality of life and extended survival. Future efforts should be directed at early diagnosis, improving the tolerability and efficacy of anti-plasma cell therapy, accelerating recovery of organ function via promoting resorption of amyloid deposits, and developing novel approaches to counter light chain proteotoxicity.

Systemic amyloidoses: what an internist should know

Systemic amyloidoses are rare, complex diseases caused by misfolding of autologous proteins. Although these diseases are fatal, effective treatments exist that can alter their natural history, provided that they are started before irreversible organ damage has occurred. The cornerstones of the management of systemic amyloidoses are early diagnosis, accurate typing, appropriate risk-adapted therapy, tight follow-up, and effective supportive treatment. Internists play a key role in suspecting the disease, thus allowing early diagnosis, starting the diagnostic workup and selecting patients that should be referred to specialized centers, judiciously titrating supportive measures, and following patients throughout the course of the disease. Here we review the pathogenesis, diagnosis and treatment of the most common forms of systemic amyloidoses.

Regulation of the proteasome by ATP: implications for ischemic myocardial injury and donor heart preservation

Several lines of evidence suggest that proteasomes are involved in multiple aspects of myocardial physiology and pathology, including myocardial ischemia-reperfusion injury. It is well established that the 26S proteasome is an ATP-dependent enzyme and that ischemic heart disease is associated with changes in the ATP content of the cardiomyocyte. A functional link between the 26S proteasome, myocardial ATP concentrations, and ischemic cardiac injury, however, has been suggested only recently. This review discusses the currently available data on the pathophysiological role of the cardiac proteasome during ischemia and reperfusion in the context of the cellular ATP content. Depletion of the myocardial ATP content during ischemia appears to activate the 26S proteasome via direct regulatory effects of ATP on 26S proteasome stability and activity. This implies pathological degradation of target proteins by the proteasome and could provide a pathophysiological basis for beneficial effects of proteasome inhibitors in various models of myocardial ischemia. In contrast to that in the ischemic heart, reduced and impaired proteasome activity is detectable in the postischemic heart. The paradoxical findings that proteasome inhibitors showed beneficial effects when administered during reperfusion in some studies could be explained by their anti-inflammatory and immune suppressive actions, leading to reduction of leukocyte-mediated myocardial reperfusion injury. The direct regulatory effects of ATP on the 26S proteasome have implications for the understanding of the contribution of the 26S proteasome to the pathophysiology of the ischemic heart and its possible role as a therapeutic target.

Profound Neurotoxicity and Treatment Response following One Cycle of Bortezomib Therapy in an Elderly Male with Multiple Myeloma

Objective:

To report a case of peripheral and autonomic neuropathy following one cycle of bortezomib in a patient with newly diagnosed multiple myeloma.

Case Summary:

A 75-year-old male who was highly functional prior to therapy rapidly became bed-bound from hypotension, syncope, and peripheral neuropathy after initiating bortezomib. Orthostatic hypotension and syncope persisted despite exclusion of infection and endocrine derangements and his receiving adequate intravenous hydration. Five weeks after this single cycle, the patient had a complete treatment response, including undetectable M-spike, improved anemia, and return to baseline renal function. An objective causality assessment revealed that an adverse drug event was probable.

Discussion:

Although neurotoxicity is an adverse effect of bortezomib, a MEDLINE search revealed little evidence on autonomic neuropathy, such as orthostatic hypotension and syncope. Also unique is the patient's complete treatment response following this single cycle. One explanation for the toxicities and dramatic treatment response is increased bortezomib exposure due to decreased drug metabolism. Both drug interactions and genetic polymorphisms can reduce bortezomib metabolism via effects on cytochrome P450 enzymes. Our patient was concomitantly taking 4 CYP inhibitors; amiodarone and omeprazole were longstanding, and ciprofloxacin and fluconazole were recently initiated prior to chemotherapy. Of these, fluconazole inhibits CYP2C9, 2C19, and 3A4; amiodarone inhibits CYP3A4, 1A1, 1A2, 2B6, and 2D6; ciprofloxacin inhibits CYP1A2 and 3A4; and omeprazole inhibits CYP1A2, 2C19, 2C9, 2D6, and 3A4. Similarly, genetic variables affect CYP enzymes. Genetic testing can predict response to bortezomib therapy, but pretherapy testing is not standard practice due to availability and cost, as in our patient's case.

Conclusions:

CYP-inhibiting drugs and many genetic polymorphisms can reduce bortezomib metabolism and increase serum concentrations of the drug, but guidelines on drug-drug interactions, monitoring, and genetic testing prior to bortezomib toxicity are needed.

Amyloid diseases of the heart: current and future therapies

Amyloid diseases in man are caused by as many as 23 different pre-cursor proteins already described. Cardiologists predominantly encounter three main types of amyloidosis that affect the heart: light chain (AL) amyloidosis, senile systemic amyloidosis (SSA) and hereditary amyloidosis, most commonly caused by a mutant form of transthyretin. In the third world, secondary amyloid (AA) is more prevalent, due to chronic infections and inadequately treated inflammatory conditions. Much less common, are the non-transthyretin variants, including mutations of fibrinogen, the apolipoproteins apoA1 and apoA2 and gelsolin. These rarer types do not usually cause significant cardiac compromise. Occurring worldwide, later in life and of less clinical significance, isolated atrial amyloid (IAA) also involves the heart. Heart involvement by amyloid often has devastating consequences. Clinical outcome depends on amyloid type, the extent of systemic involvement and the treatment options available. An exact determination of amyloid type is critical to appropriate therapy. In this review we describe the different approaches required to treat this spectrum of amyloid cardiomyopathies.

Cyclophosphamide, bortezomib, and dexamethasone therapy in AL amyloidosis is associated with high clonal response rates and prolonged progression-free survival

Bortezomib has shown great promise in the treatment of amyloid light-chain (AL) amyloidosis. We present our experience of 43 patients with AL amyloidosis who received cyclophosphamide, bortezomib, and dexamethasone (CVD) upfront or at relapse. Of these, 74% had cardiac involvement and 46% were Mayo Cardiac Stage III. The overall hematologic response rate was 81.4%, including complete response (CR) in 41.9% and very good partial response with >90% decrease in difference between involved/uninvolved light chain (VGPR-dFLC) in 51.4%. Patients treated upfront had higher rates of CR (65.0%) and VGPR-dFLC (66.7%). The estimated 2-year progression-free survival was 66.5% for patients treated upfront and 41.4% for relapsed patients. Those attaining a CR or VGPR-dFLC had a significantly better progression-free survival (P=.002 and P=.026, respectively). The estimated 2-year overall survival was 97.7% (94.4% in Mayo Stage III patients). CVD is a highly effective regimen producing durable responses in AL amyloidosis; the deep clonal responses may overcome poor prognosis in advanced-stage disease.