A phase II, open-label, extension study of long-term patisiran treatment in patients with hereditary transthyretin-mediated (hATTR) amyloidosis

BACKGROUND

Patisiran, an RNA interference therapeutic, has demonstrated robust reduction of wild-type and mutant transthyretin protein and was able to improve polyneuropathy and quality of life following 18 months of treatment in patients with hereditary transthyretin-mediated (hATTR) amyloidosis. In this 24-month Phase II open-label extension study, we evaluated the effects of patisiran treatment (0.3 mg/kg intravenously every 3 weeks) on safety, serum transthyretin levels, and clinical parameters. Efficacy assessments included modified Neuropathy Impairment Score +7 (mNIS+7) and multiple disease-relevant measures. Cardiac assessments were performed in a pre-specified cardiac subgroup.

RESULTS

Twenty-seven patients entered this study, including 12 (44%) with ambulation difficulties due to their neuropathy and 11 (41%) who met criteria for the cardiac subgroup. During treatment, the majority of adverse events were mild/moderate in severity; there were no drug-related adverse events leading to treatment discontinuation. The most common drug-related adverse events were flushing and infusion-related reactions (22% each). Patisiran resulted in rapid, robust (~ 82%), and sustained reduction of mean transthyretin levels over 24 months. A mean 6.95-point decrease (improvement) in mNIS+7 from baseline was observed at 24 months. Patisiran's impact on mNIS+7 was irrespective of concomitant tafamidis or diflunisal use, sex, or age. Clinical assessments of motor function, autonomic symptoms, disease stage, and quality of life remained stable over 24 months. No significant changes were observed for echocardiographic measures or cardiac biomarkers in the cardiac subgroup. Exploratory analyses demonstrated improvements in nerve-fiber density with corresponding reductions in amyloid burden observed in skin biopsies over 24 months.

CONCLUSIONS

Long-term treatment with patisiran had an acceptable safety profile and was associated with halting/improvement of polyneuropathy progression in patients with hATTR amyloidosis.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (identifier: NCT01961921 ) on October 14, 2013.

Patisiran, an RNAi Therapeutic, for Hereditary Transthyretin Amyloidosis

BACKGROUND

Patisiran, an investigational RNA interference therapeutic agent, specifically inhibits hepatic synthesis of transthyretin.

METHODS

In this phase 3 trial, we randomly assigned patients with hereditary transthyretin amyloidosis with polyneuropathy, in a 2:1 ratio, to receive intravenous patisiran (0.3 mg per kilogram of body weight) or placebo once every 3 weeks. The primary end point was the change from baseline in the modified Neuropathy Impairment Score+7 (mNIS+7; range, 0 to 304, with higher scores indicating more impairment) at 18 months. Other assessments included the Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) questionnaire (range, -4 to 136, with higher scores indicating worse quality of life), 10-m walk test (with gait speed measured in meters per second), and modified body-mass index (modified BMI, defined as [weight in kilograms divided by square of height in meters]×albumin level in grams per liter; lower values indicated worse nutritional status).

RESULTS

A total of 225 patients underwent randomization (148 to the patisiran group and 77 to the placebo group). The mean (±SD) mNIS+7 at baseline was 80.9±41.5 in the patisiran group and 74.6±37.0 in the placebo group; the least-squares mean (±SE) change from baseline was -6.0±1.7 versus 28.0±2.6 (difference, -34.0 points; P<0.001) at 18 months. The mean (±SD) baseline Norfolk QOL-DN score was 59.6±28.2 in the patisiran group and 55.5±24.3 in the placebo group; the least-squares mean (±SE) change from baseline was -6.7±1.8 versus 14.4±2.7 (difference, -21.1 points; P<0.001) at 18 months. Patisiran also showed an effect on gait speed and modified BMI. At 18 months, the least-squares mean change from baseline in gait speed was 0.08±0.02 m per second with patisiran versus -0.24±0.04 m per second with placebo (difference, 0.31 m per second; P<0.001), and the least-squares mean change from baseline in the modified BMI was -3.7±9.6 versus -119.4±14.5 (difference, 115.7; P<0.001). Approximately 20% of the patients who received patisiran and 10% of those who received placebo had mild or moderate infusion-related reactions; the overall incidence and types of adverse events were similar in the two groups.

CONCLUSIONS

In this trial, patisiran improved multiple clinical manifestations of hereditary transthyretin amyloidosis. (Funded by Alnylam Pharmaceuticals; APOLLO ClinicalTrials.gov number, NCT01960348 .).

Extracellular Volume Detects Amyloidotic Cardiomyopathy and Correlates With Neurological Impairment in Transthyretin-familial Amyloidosis

INTRODUCTION AND OBJECTIVES

Cardiac involvement determines prognosis and treatment options in transthyretin-familial amyloidosis. Cardiac magnetic resonance T₁ mapping techniques are useful to assess myocardial extracellular volume. This study hypothesized that myocardial extracellular volume allows identification of amyloidotic cardiomyopathy and correlates with the degree of neurological impairment in transthyretin-familial amyloidosis.

METHODS

A total of 31 transthyretin-familial amyloidosis patients (19 mean age, 49 ± 12 years; 26 with the Val30Met mutation) underwent a T₁ mapping cardiac magnetic resonance study and a neurological evaluation with Neuropathy Impairment Score of the Lower Limb score, Norfolk Quality of Life questionnaire, and Karnofsky index.

RESULTS

Five patients had cardiac amyloidosis (all confirmed by ^99mTc-DPD scintigraphy). Mean extracellular volume was increased in patients with cardiac amyloidosis (0.490 ± 0.131 vs 0.289 ± 0.035; P = .026). Extracellular volume correlated with age (R = 0.467; P = .008), N-terminal pro-B-type natriuretic peptide (R_S = 0.846; P < .001), maximum wall thickness (R = 0.621; P < .001), left ventricular mass index (R = 0.685; P < .001), left ventricular ejection fraction (R = -0.378; P = .036), Neuropathy Impairment Score of the Lower Limb (R_S = 0.604; P = .001), Norfolk Quality of Life questionnaire (R_S = 0.529; P = .003) and Karnofsky index (R_S= -0.517; P = .004). A cutoff value of extracellular volume of 0.357 was diagnostic of cardiac amyloidosis with 100% sensitivity and specificity (P < .001). Extracellular volume and N-terminal pro-B-type natriuretic peptide were the only cardiac parameters that significantly correlated with neurologic scores.

CONCLUSIONS

Extracellular volume quantification allows identification of cardiac amyloidosis and correlates with the degree of neurological impairment in transthyretin-familial amyloidosis. This noninvasive technique could be a useful tool for early diagnosis of cardiac amyloidosis and to track cardiac and extracardiac amyloid disease.

PHASE 2 OPEN-LABEL EXTENSION STUDY OF PATISIRAN, AN INVESTIGATIONAL RNAI THERAPEUTIC FOR THE TREATMENT OF FAMILIAL AMYLOID POLYNEUROPATHY

Familial amyloid polyneuropathy (FAP) is a progressive disease. Patisiran is an investigational small interfering RNA (siRNA) targeting TTR. The primary objective of the Phase 2 study is to evaluate the safety of 0.3 mg/kg patisiran administered intravenously once every 3 weeks. Twenty-seven patients were enrolled; the mean duration of treatment was 7 months (range 3–12), with 282 doses administered (median of 11 doses/patient). Chronic dosing with patisiran has been generally well tolerated. Two patients experienced serious adverse events regarded as being unrelated to study drug. Infusion-related reactions were observed in 14.8% of the patients, were mild in severity, and did not result in any discontinuations. Sustained TTR lowering of at least 80% was achieved based on serial TTR measurements for over 9 months, with further nadir of up to 89.6% between doses. Neurologic impairment scores were stable after 6 months of treatment with patisiran. A mean decrease from baseline in mNIS+7 of 0.95 points (N=19) observed in this study compared favorably to the estimated increase of 7–10 points in mNIS+7 at 6 months from prior FAP studies in a patient population with similar baseline NIS values. Dosing continues in all patients, and 12–month results will be presented.

Efficacy and safety of patisiran for familial amyloidotic polyneuropathy: a phase II multi-dose study

BACKGROUND

Transthyretin-mediated amyloidosis is an inherited, progressively debilitating disease caused by mutations in the transthyretin gene. This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple doses of patisiran (ALN-TTR02), a small interfering RNA encapsulated within lipid nanoparticles, in patients with transthyretin-mediated familial amyloid polyneuropathy (FAP).

METHODS

In this phase II study, patients with FAP were administered 2 intravenous infusions of patisiran at one of the following doses: 0.01 (n = 4), 0.05 (n = 3), 0.15 (n = 3), or 0.3 (n = 7) mg/kg every 4 weeks (Q4W), or 0.3 mg/kg (n = 12) every 3 weeks (Q3W).

RESULTS

Of 29 patients in the intent-to-treat population, 26 completed the study. Administration of patisiran led to rapid, dose-dependent, and durable knockdown of transthyretin, with the maximum effect seen with patisiran 0.3 mg/kg; levels of mutant and wild-type transthyretin were reduced to a similar extent in Val30Met patients. A mean level of knockdown exceeding 85 % after the second dose, with maximum knockdown of 96 %, was observed for the Q3W dose. The most common treatment-related adverse event (AE) was mild-to-moderate infusion-related reactions in 10.3 % of patients. Four serious AEs (SAEs) were reported in 1 patient administered 0.3 mg/kg Q3W (urinary tract infection, sepsis, nausea, vomiting), and 1 patient administered 0.3 mg/kg Q4W had 1 SAE (extravasation-related cellulitis).

CONCLUSIONS

Patisiran was generally well tolerated and resulted in significant dose-dependent knockdown of transthyretin protein in patients with FAP. Patisiran 0.3 mg/kg Q3W is currently in phase III development.

TRIAL REGISTRATION NUMBER

NCT01617967 .

Use of adsorptive mechanisms in continuous renal replacement therapies in the critically ill

The pathophysiology of sepsis is becoming a more complicated scenario. In sepsis, endotoxin or other gram-positive derived products induce a complex and dynamic cellular response giving rise to several mediators known to be relevant in the pathogenesis of septic shock, such as specific mediators. substances responsible for up- or down-regulation of cytokine receptors and cytokine antagonists, inactivators of nuclear factor-kappaB or signal transduction pathways, and precursor molecules. In this article, we delve into some new concepts stemming from the use of sorbents in continuous plasma filtration. The rationale is based on the assumption that the nonspecific removal of several mediators of the inflammatory cascade and cytokine network may improve outcome in a rabbit model of septic shock and hemodynamics in a pilot clinical study. The importance of looking for innovative treatments specifically targeted for the special needs of the critically ill patients rather than using concepts and technology applied to the treatment of chronic renal failure is underlined.

Relevance of platelet-activating factor in inflammation and sepsis: mechanisms and kinetics of removal in extracorporeal treatments

Sepsis can be considered a systemic inflammatory response syndrome (SIRS) caused by infection. When an excessive and/or persistent activation of humoral and cellular mechanisms of host defense is present, an exaggerated and generalized activation of inflammatory mechanisms can lead to a multiple organ dysfunction syndrome. Mediators thought to be involved in this syndrome include the major plasma cascade systems (complement, coagulation, and fibrinolytic systems) and soluble cell-derived mediators (cytokines, reactive oxygen species, platelet-activating factor (PAF), arachidonic acid metabolites, and nitric oxide and related compounds). Several findings indicate that among these mediators, PAF may exert an important role in the pathophysiology of septic shock. Evidence is accumulating that in human sepsis this scenario is far more complicated and that removal of inflammatory mediator excess from plasma, rather than blockade of their potentially beneficial local production, might provide a rationale for the use of continuous renal replacement therapy (CRRT). There is an emerging view that CRRT should be considered in the light of broader concept (ie, the use of blood purification for the treatment of sepsis). Recent studies, performed in an experimental model of continuous arteriovenous hemofiltration with exogenous PAF, demonstrated that polysulfone membranes can adsorb substantial amounts of biologically active PAF. These studies also showed that the removal of this mediator occurs by a two-step process involving early adsorption followed by ultrafiltration. Although the removal of cytokines, such as tumor necrosis factor-alpha (TNF-alpha), remains controversial, mainly because of differences in membrane used, operational conditions, and inter- and intra-assay variability, the crucial point is that no evidence has yet been given to show real benefit from CRRT in significantly reducing the plasma concentration of cytokines. The net advantage of CRRT, however, may not only be the removal of cytokines per se, but also the simultaneous elimination of cytokine-inducing substances. Experimental and human studies will be discussed as to whether extracorporeal treatments may remove an excess of circulating cytokines, either by increasing the turnover rate (the so-called high-volume hemofiltration), or by using sorbent systems to regenerate plasma filtrate.

Familial Mediterranean fever in the "Chuetas" of Mallorca--origin in inquisition?

The aim of our study was to compare the features of familial Mediterranean fever (FMF) in Mallorcan "Chuetas" with those in non-Ashkenazi Jews in Israel. The clinical and laboratory data of FMF were evaluated in a recently identified cluster of 50 FMF patients from Mallorca (the Chuetas) and 45 patients from Israel. We found that the prevalence and clinical manifestations of FMF were similar among the Chuetas and the Israeli group. Furthermore, in contrast to other ethnic groups with FMF, joint involvement was quite common in both the Chuetas (70%) and the Israeli group (75%). The Chuetas are descendants of Mallorcan Jews who emigrated from Spain to the island in the 12th century. The non-Ashkenazi Jews originated mainly in North Africa and are descendants of refugees who escaped from Spain as a result of the Inquisition in the 15th century. We suggest that the non-Ashkenazi Jews and the Chuetas may have a common gene defect for FMF.

Laryngeal leishmaniasis as initial opportunistic disease in HIV infection

A case of laryngeal leishmaniasis, with symptoms of hoarseness and odinophagia which had developed over the past year, is presented. Clinical features and histological findings are discussed. Visceral leishmaniasis is increasingly associated with HIV infection and some authors have suggested the possibility of including it as a diagnostic criterium for AIDS in HIV-positive patients. When any case of leishmaniasis presents atypical clinical features, localization or treatment response in endemic areas, HIV infection should be ruled out.

Visceral leishmaniasis: another HIV-associated opportunistic infection? Report of eight cases and review of the literature

Visceral leishmaniasis (VL) is considered an opportunistic infection in immunocompromised patients. We review the clinical, laboratory, and therapeutic data in 63 patients (eight new cases and 55 cases reported in the literature) with Mediterranean VL (kala azar) and HIV-1 infection to determine whether VL should be considered an opportunistic infection in HIV-infected adults. We conclude that: (1) in areas where both leishmaniasis and HIV-1 infection are endemic, VL may be more frequent among HIV-infected adults; (2) in HIV-infected patients, the clinical picture did not differ significantly from classical kala azar, although it often ran a recurrent course, with resistance to antimonial therapy. We propose the inclusion of VL in the IVC-2 subgroup of the Centers for Disease Control (CDC) clinical classification of HIV-1 infection while prospective and larger studies further define whether there are clinical presentations that could justify adding VL to the list of opportunistic infections indicative of AIDS.