New concepts in the treatment and diagnosis of amyloidosis

The Clinical Characteristics and Prognosis of Chinese Patients with Light-Chain Amyloidosis: A Retrospective Multicenter Analysis

To retrospectively identify the critical characteristics and prognostic factors of light-chain amyloidosis. Patients and Methods: Data were collected and compared from 91 patients who were diagnosed with light-chain amyloidosis at four hospitals between January 2010 and November 2018. We analyzed the clinical characteristics and performed an overall survival (OS) analysis. Results: Patients (median age, 60 years) were diagnosed with organ involvement of the kidney (91.2%), heart (56%), liver (14.3%), soft tissue (18.7%), or gastrointestinal tract (15.4%), and 68.1% of patients had more than two organs involved. Patients were most treated with bortezomib-based regimens (56%), and only one patient had autologous stem cell transplantation (auto-ASCT). The median OS was 36.33 months and was influenced by the ECOG score, renal involvement, cardiac involvement, hepatic involvement, and persistence of positive immunofixation. Patients who received bortezomib-based treatment had a trend of favorable OS compared to those who received non-bortezomib-based treatments, but the difference was not statistically significant. Although the overall number of organs involved was not related to OS, the number of organs involved in the heart, liver and kidney was related. Multivariate analysis indicated that cardiac involvement and negative hematologic response with persistence of positive immunofixation were independent prognostic factors for OS. Conclusion: Cardiac involvement and the hematologic response to treatment were independent prognostic factors for OS in light-chain amyloidosis patients.

Pharmacologic targeting of plasma cell endoplasmic reticulum proteostasis to reduce amyloidogenic light chain secretion

Light chain (LC) amyloidosis (AL) involves the toxic aggregation of amyloidogenic immunoglobulin LCs secreted from a clonal expansion of diseased plasma cells. Current AL treatments use chemotherapeutics to ablate the AL plasma cell population. However, no treatments are available that directly reduce the toxic LC aggregation involved in AL pathogenesis. An attractive strategy to reduce toxic LC aggregation in AL involves enhancing endoplasmic reticulum (ER) proteostasis in plasma cells to reduce the secretion and subsequent aggregation of amyloidogenic LCs. Here, we show that the ER proteostasis regulator compound 147 reduces secretion of an amyloidogenic LC as aggregation-prone monomers and dimers in AL patient-derived plasma cells. Compound 147 was established to promote ER proteostasis remodeling by activating the ATF6 unfolded protein response signaling pathway through a mechanism involving covalent modification of ER protein disulfide isomerases (PDIs). However, we show that 147-dependent reductions in amyloidogenic LCs are independent of ATF6 activation. Instead, 147 reduces amyloidogenic LC secretion through the selective, on-target covalent modification of ER proteostasis factors, including PDIs, revealing an alternative mechanism by which this compound can influence ER proteostasis of amyloidogenic proteins. Importantly, compound 147 does not interfere with AL plasma cell toxicity induced by bortezomib, a standard chemotherapeutic used to ablate the underlying diseased plasma cells in AL. This shows that pharmacologic targeting of ER proteostasis through selective covalent modification of ER proteostasis factors is a strategy that can be used in combination with chemotherapeutics to reduce the LC toxicity associated with AL pathogenesis.

Cardiac amyloidosis-an underdiagnosed cause of heart failure in the elderly

Amyloidosis is a rare, generally multisystem disease that can also involve the heart. Infiltration of the myocardium with amyloid proteins is an important and underappreciated cause of heart failure with preserved ejection fraction in the elderly. We present the case of an 84-year-old man with chest tightness, dyspnoea, and ascites. He had a history of dyslipidaemia and ischaemic heart disease. Initial investigations showed severe diastolic dysfunction and elevated pulmonary artery systolic pressure on echocardiogram along with elevated serum natriuretic peptides. Further evaluation by a magnetic resonance imaging scan of the heart and endomyocardial biopsy confirmed the diagnosis of senile systemic amyloidosis. He made good progress after treatment with conventional heart failure drugs and is currently under consideration to start on specific medications to slow down the progression of amyloidosis. This case aims to increase clinicians' awareness of senile amyloidosis as a cause of heart failure in the elderly.

Melflufen: A Peptide-Drug Conjugate for the Treatment of Multiple Myeloma

Despite the availability of new therapies that have led to improved outcomes for patients with multiple myeloma, most patients will eventually relapse. With triplet and even quadruplet combination therapies becoming standard in the first and second line, many patients will have few treatment options after second-line treatment. Melflufen (melphalan flufenamide) is a first-in-class peptide-drug conjugate (PDC) that targets aminopeptidases and rapidly releases alkylating agents into tumor cells. Once inside the tumor cells, melflufen is hydrolyzed by peptidases to release alkylator molecules, which become entrapped. Melflufen showed anti-myeloma activity in myeloma cells that were resistant to bortezomib and the alkylator melphalan. In early phase studies (O-12-M1 and HORIZON [OP-106]), melflufen plus dexamethasone has demonstrated encouraging clinical activity and a manageable safety profile in heavily pretreated patients with relapsed/refractory multiple myeloma, including those with triple-class refractory disease and extramedullary disease. The Phase III OCEAN study (OP-104) is further evaluating melflufen plus dexamethasone in patients with relapsed/refractory multiple myeloma. The safety profile of melflufen is characterized primarily by clinically manageable hematologic adverse events. Melflufen, with its novel mechanism of action, has the potential to provide clinically meaningful benefits to patients with relapsed/refractory multiple myeloma, including those with high unmet needs.

Role of urine immunofixation in the complete response assessment of MM patients other than light-chain-only disease

Response criteria for multiple myeloma (MM) require monoclonal protein (M-protein)–negative status on both serum immunofixation electrophoresis (sIFE) and urine (uIFE) immunofixation electrophoresis for classification of complete response (CR). However, uIFE is not always performed for sIFE-negative patients. We analyzed M-protein evaluations from 384 MM patients (excluding those with light-chain-only disease) treated in the GEM2012MENOS65 (NCT01916252) trial to determine the uIFE-positive rate in patients who became sIFE-negative posttreatment and evaluate rates of minimal residual disease (MRD)–negative status and progression-free survival (PFS) among patients achieving CR, CR but without uIFE available (uncertain CR; uCR), or very good partial response (VGPR). Among 107 patients with M-protein exclusively in serum at diagnosis who became sIFE-negative posttreatment and who had uIFE available, the uIFE-positive rate was 0%. Among 161 patients with M-protein in both serum and urine at diagnosis who became sIFE-negative posttreatment, 3 (1.8%) were uIFE positive. Among patients achieving CR vs uCR, there were no significant differences in postconsolidation MRD-negative (<10−6; 76% vs 75%; P = .9) and 2-year PFS (85% vs 88%; P = .4) rates; rates were significantly lower among patients achieving VGPR. Our results suggest that uIFE is not necessary for defining CR in MM patients other than those with light-chain-only disease.

Macroglossia, the first manifestation of systemic amyloidosis associated with multiple myeloma: Case report

Amyloidosis is a group of diseases characterized by an irreversible and extracellular deposition of fibrillar, amorphous protein known as amyloid in different organs and tissues. Amyloid deposits may occur locally in tissues or may involve various organs, resulting in a wide range of clinical manifestations. Amyloidosis of the head and neck is rarely seen and can reflect some plasma cell dyscrasia that affects B lymphocytes. Deposition of amyloid on the tongue is very rare and accounts for less than 9% of all types of amyloidosis. Amyloid involvement of the tongue is almost always secondary to systemic amyloidosis. We report a 73-year-old female who presented with weight loss and macroglossia. Firstly, she was diagnosed only with amyloidosis of the tongue. Her general health condition was evaluated, revealing renal dysfunction, anemia, hypercalcemia, and hyperphosphatemia. The final diagnosis was systemic amyloidosis with multiple myeloma. The patient was referred for emergency hemodialysis and chemotherapy. Her condition progressed to congestive heart failure and recurrent urinary and respiratory infections. After 100 days from diagnosis, the patient died by pulmonary infection as a consequence of her weakened state of health. It is important to highlight role of the dentist especially oral pathologist to the evaluation of local alterations that may reflect systemic deterioration of patients.