Amyloid Polyneuropathy and Myocardial Amyloidosis 10 Years after Domino Liver Transplantation from a Patient with a Transthyretin Ser50Arg Mutation

Safety, Tolerability, and Outcomes of Tafamidis for the Treatment of Acquired Amyloid Neuropathy in Domino Liver Transplant Recipients

INTRODUCTION

Acquired amyloid neuropathy is an iatrogenic disease that appears years after a domino liver transplant. The objectives of our study are to analyze the efficacy and tolerability of tafamidis for the treatment of acquired amyloid neuropathy in domino liver transplant recipients. This post-authorization, prospective, longitudinal study included seven domino liver transplant recipients with acquired amyloid neuropathy who received treatment with tafamidis for 18 months.

METHODS

The primary endpoints were the response rate, defined as those patients with an increase of < 2 points on the Neurological Impairment Score (NIS) from baseline, and the change in the NIS score from baseline. Secondary endpoints included the Quantitative Sensory Test, 10-m walk test, quality of life (Norfolk), and disability (Rasch-built Overall Disability Scale). As safety parameters, the evidence of graft rejection, changes in immunosuppressive trough levels and changes in antiviral and allogeneic cellular immunity before and 12 months after tafamidis treatment were also assessed.

RESULTS

Six patients (85.7%) had responded at 18-months. Compared to baseline, we observed non-statistically significant improvement in mean NIS score at 6 months (- 2.54 points, CI - 5.92 to 0.84), 12 months (- 3.25 points; CI - 6.63 to 0.13), and 18 months (- 2.35 points; CI - 5.74 to 1.02). Changes in the Quantitative Sensory Test, 10-m walk tests and the quality of life and disability questionnaires were not statistically significant. The use of tafamidis did not induce relevant side effects or drug interactions. Also, no acute rejections events nor changes in functional adaptive immunity were observed.

CONCLUSION

Our study supports the safety and tolerability of tafamidis for the treatment of acquired amyloid neuropathy in domino liver transplant recipients. Tafamidis shows promise as a useful treatment in the clinical management of these patients. Future randomized placebo-controlled clinical trials with longer follow-up durations are needed.

Does Patisiran Reduce Ocular Transthyretin Synthesis? A Pilot Study of Two Cases

BACKGROUND

Variant transthyretin-mediated amyloidosis (ATTR-v) is a well-characterized disease affecting the neurologic and cardiovascular systems. Patisiran has been approved for neurologic involvement as it reduces hepatic synthesis of transthyretin (TTR). Eye involvement is a lateonset feature increasing the risk of glaucoma and cataracts in patients.

AIMS

The aim of this case series was to assess whether patisiran can effectively reduce TTR synthesis in such a barrier-protected organ as the eye.

METHODS

Two patisiran-treated ATTR-v patients underwent serum and aqueous humor sampling to measure TTR levels detected by SDS-PAGE and immunoblotting. Serum samples were compared to healthy control (HC), whereas aqueous humor samples were compared to non-amyloidotic subjects affected by cataracts and glaucoma.

RESULTS

Serum TTR levels representative of hepatic synthesis were sharply lower in treated patients if compared to the HC (-87.5% and -93.75%, respectively). Aqueous humor TTR levels showed mild-tono reduction in treated patients compared to non-amyloidotic subjects with cataracts (-34.9% and +8.1%, respectively) and glaucoma (-41.1% and -2.1%).

CONCLUSION

Patisiran does not seem to be as effective in inhibiting ocular TTR synthesis as it is in inhibiting hepatic synthesis. Re-engineering the envelope could allow the drug to target RPE cells thus avoiding any ocular involvement.

Treatment With Diflunisal in Domino Liver Transplant Recipients With Acquired Amyloid Neuropathy

Objectives: To analyze the efficacy and tolerability of diflunisal for the treatment of acquired amyloid neuropathy in domino liver transplant recipients. Methods: We performed a retrospective longitudinal study of prospectively collected data for all domino liver transplant recipients with acquired amyloid neuropathy who received diflunisal at our hospital. Neurological deterioration was defined as an score increase of ≥2 points from baseline on the Neurological Impairment Scale/Neurological Impairment Scale-Lower Limbs. Results: Twelve patients who had received compassionate use treatment with diflunisal were identified, of whom seven had follow-up data for ≥12 months. Five patients (71.4%) presented with neurological deterioration on the Neurological Impairment Scale after 12 months (p = 0.0382). The main adverse effects were cardiovascular and renal, leading to diflunisal being stopped in five patients and the dose being reduced in two patients. Conclusion: Our study suggests that most domino liver transplant recipients with acquired amyloid neuropathy will develop neurological deterioration by 12 months of treatment with diflunisal. This therapy was also associated with a high incidence of adverse effects and low treatment retention. The low efficacy and low tolerability of diflunisal treatment encourage the search for new therapeutic options.

Canadian Guidelines for Hereditary Transthyretin Amyloidosis Polyneuropathy Management

Hereditary transthyretin-mediated (hATTR) amyloidosis is a progressive disease caused by mutations in the TTR gene leading to multisystem organ dysfunction. Pathogenic TTR aggregation, misfolding, and fibrillization lead to deposition of amyloid in multiple body organs and frequently involve the peripheral nerve system and the heart. Common neurologic manifestations include: sensorimotor polyneuropathy (PN), autonomic neuropathy, small-fiber PN, and carpal tunnel syndrome. Many patients have significant progression due to diagnostic delays as hATTR PN is not considered within the differential diagnosis. Recently, two effective novel disease-modifying therapies, inotersen and patisiran, were approved by Health Canada for the treatment of hATTR PN. Early diagnosis is crucial for the timely introduction of these disease-modifying treatments that reduce impairments, improve quality of life, and extend survival. In this guideline, we aim to improve awareness and outcomes of hATTR PN by making recommendations directed to the diagnosis, monitoring, and treatment in Canada.

Transthyretin amyloidosis with cardiomyopathy after domino liver transplantation: Results of a cross-sectional study

Domino liver transplantation (DLT) has been used widely in patients with hereditary amyloid transthyretin (ATTR) amyloidosis. New-onset polyneuropathy in recipients of DLT has been reported, but there are few cases of cardiac involvement reported. We aimed to perform a cross-sectional study for ATTR amyloidosis with cardiomyopathy (ATTR-CM) in DLT recipients. We evaluated 23 living DLT recipients a median of 9 years since DLT at 2 referral centers with a systematic cardiac evaluation, including bone scintigraphy. Median age was 72 years, 91% had hypertension, 35% had diabetes mellitus, 67% had chronic renal failure, and 8 patients (35%) developed new-onset polyneuropathy. Only 13% had a normal electrocardiogram and a normal echocardiography, and most of them showed some conduction disturbance or increase in left ventricular wall thickness, but only 1 patient with a Glu89Lys mutation developed ATTR-CM diagnosed by bone scintigraphy and endomyocardial biopsy. None of the recipients of a DLT with Val30Met mutation showed cardiac involvement by bone scintigraphy. In conclusion, DLT from Val30Met donors seems to be safe regarding the development of ATTR-CM. Evaluation of cardiomyopathy in DLT recipients is challenging due to concomitant comorbidities and in this context, bone scintigraphy can be helpful to evaluate ATTR-CM.

Temporal Change in Longitudinal Strain After Domino Liver Transplantation With Liver Grafts Explanted From Patients With Hereditary Amyloidogenic Transthyretin Amyloidosis

Background: Using transthoracic echocardiography, including 2D speckle tracking imaging (STI), this study examined cardiac function after domino liver transplantation (DLT) with liver grafts explanted from patients with hereditary amyloidogenic transthyretin amyloidosis.

Methods and Results: In all, 14 patients who underwent DLT at Kumamoto University Hospital and for whom 2D STI information was available were enrolled in the study; time-dependent echocardiographic changes were evaluated in 7. Although left ventricular (LV) systolic and diastolic function did not differ between the pre- and post-DLT periods (mean [±SD] 5.4±1.0 years after DLT), there were significant (P<0.05 for all) increases in the post- vs. pre-DLT period in basal longitudinal strain (LS; −13.4±2.3 vs. −19.3±4.4), relative apical LS index (=apical LS/[basal LS+mid LS]; 0.75±0.20 vs. 0.58±0.08), and LV ejection fraction/global LS (3.91±0.58 vs. 3.06±0.44). Age at the time of DLT was significantly higher in the group with impaired (>−14%) than preserved basal LS (57.2±3.5 vs. 39.6±16.0 years; P<0.05). When control subjects (n=14) were added to the enrolled DLT recipients, multivariable logistic regression analysis revealed that a history of DLT was significantly associated with impaired basal LS (>−14%; odds ratio 28.39, 95% confidence interval 1.89–427.45, P<0.05).

Conclusions: LV systolic and diastolic function was preserved in the long term after DLT. However, 2D STI revealed subtle cardiac dysfunction in DLT recipients, which may be an early manifestation of cardiac amyloidosis.

Amyloidosis in Heart Failure

PURPOSE

Amyloidosis represents an increasingly recognized but still frequently missed cause of heart failure. In the light of many effective therapies for light chain (AL) amyloidosis and promising new treatment options for transthyretin (ATTR) amyloidosis, awareness among caregivers needs to be raised to screen for amyloidosis as an important and potentially treatable differential diagnosis. This review outlines the diversity of cardiac amyloidosis, its relation to heart failure, the diagnostic algorithm, and therapeutic considerations that should be applied depending on the underlying type of amyloidosis.

RECENT FINDINGS

Non-biopsy diagnosis is feasible in ATTR amyloidosis in the absence of a monoclonal component resulting in higher detection rates of cardiac ATTR amyloidosis. Biomarker-guided staging systems have been updated to facilitate risk stratification according to currently available biomarkers independent of regional differences, but have not yet prospectively been tested. Novel therapies for hereditary and wild-type ATTR amyloidosis are increasingly available. The complex treatment options for AL amyloidosis are improving continuously, resulting in better survival and quality of life. Mortality in advanced cardiac amyloidosis remains high, underlining the importance of early diagnosis and treatment initiation. Cardiac amyloidosis is characterized by etiologic and clinical heterogeneity resulting in a frequently delayed diagnosis and an inappropriately high mortality risk. New treatment options for this hitherto partially untreatable condition have become and will become available, but raise challenges regarding their implementation. Referral to specialized centers providing access to extensive and targeted diagnostic investigations and treatment initiation may help to face these challenges.

Characteristics of acquired transthyretin amyloidosis: A case series and review of the literature

OBJECTIVE

To elucidate the clinical characteristics of acquired ATTR amyloidosis after domino liver transplantation (DLT) with liver grafts explanted from patients with hereditary variant ATTR (ATTRv) amyloidosis.

METHODS

We evaluated the presence of amyloid deposits and clinical symptoms in 30 recipients of domino liver transplants (24 men and 6 women) who underwent DLT with liver grafts explanted from patients with ATTRv amyloidosis. We analyzed symptoms and measures of 7 cases of symptomatic acquired ATTR amyloidosis and compared those with 30 patients with ATTRv amyloidosis who were the domino liver donors. We also reviewed the literature on case studies of acquired ATTR amyloidosis.

RESULTS

We found amyloid deposition in 13 of our 30 domino liver recipients. A Kaplan-Meier analysis estimated that the median time from DLT to the first detection of amyloid was 8.5 years. In the literature review, the mean time was 7.3 years, with a wide range of 0.5-13 years. Our 7 symptomatic cases and the literature cases with acquired ATTR amyloidosis presented with clinical features that differed from patients with ATTRv amyloidosis who were the domino liver donors. Patients with acquired ATTR amyloidosis showed markedly milder autonomic disturbance, which is one of the main symptoms of ATTRv amyloidosis.

CONCLUSIONS

Careful monitoring is required for DLT recipients of ATTRv liver grafts because the time from DLT to disease onset has a wide range and the clinical picture of these DLT recipients is distinct from that of liver donors.