RESUMO
Hereditary transthyretin amyloidosis (ATTRv) is a rare, progressive, and life-threatening disease caused by misfolded transthyretin (TTR) proteins that aggregate as abnormal amyloid fibrils and accumulate throughout the body. The kidney is one of the main organs affected in amyloid light chain (AL) amyloidosis and ATTRv amyloidosis. The most common clinical presentation is proteinuria, which consists mainly of albumin; this is the first step in the natural history of ATTRv nephropathy. Not all TTR mutations are equal in terms of ATTRv kidney involvement. Kidney involvement in ATTRv itself is difficult to define, given the numerous associated confounding factors. There are several treatments available to treat ATTRv, including orthotopic liver transplant (OLT), which is the classic treatment for ATTRv. However, we should be careful regarding the use of calcineurin inhibitors in the setting of OLT because these can be nephrotoxic. New treatments for amyloidosis may have an impact on kidney function, including drugs that target specific pathways involved in the disease. Tafamidis and diflunisal, which are TTR stabilizers, patisiran (RNA interference agent), and inotersen (antisense oligonucleotide inhibitor) have been shown to reduce TTR amyloid. Tafamidis and patisiran are medications that have reduced the progression of kidney disease in amyloidosis, but inotersen and diflunisal may damage kidney function.
Assuntos
Neuropatias Amiloides Familiares , Benzoxazóis , Humanos , Neuropatias Amiloides Familiares/terapia , Neuropatias Amiloides Familiares/complicações , Neuropatias Amiloides Familiares/genética , Neuropatias Amiloides Familiares/diagnóstico , Benzoxazóis/uso terapêutico , Transplante de Fígado , Diflunisal/uso terapêutico , Pré-Albumina/genética , Pré-Albumina/metabolismo , Oligonucleotídeos/uso terapêutico , RNA Interferente PequenoRESUMO
La amiloidosis cardíaca es una entidad con creciente reconocimiento, la variedad por transtiretina es la que más se diagnostica en la tercera edad de la vida. Hay reciente disponibilidad de fármacos que mejoran el pronóstico y la calidad de vida de los pacientes. Presentamos un caso de amiloidosis por transtiretina donde se usó por primera vez en nuestro país el fármaco tafamidis aprobado para el tratamiento de esta enfermedad.
Cardiac amyloidosis is an entity on increasing recognition, transthyretin variety is the most diagnosed in the third age. There is a recent availability of drugs that can improve the prognosis and quality of life of these patients. We present a case of transthyretin amyloidosis and the first use of tafamidis in our country.
A amiloidose cardíaca é uma entidade em crescente reconhecimento, a variedade transtiretina é a mais diagnosticada em idosos. Há disponibilidade recente de medicamentos que melhoram o prognóstico e a qualidade de vida dos pacientes. Apresentamos um caso de amiloidosis transteretina onde o medicamento tafamidis aprovado para esta doença foi utilizado pela primeira vez em nosso país.
Assuntos
Humanos , Masculino , Idoso , Benzoxazóis/administração & dosagem , Amiloidose/diagnóstico por imagem , Cardiomiopatias , Amiloidose/tratamento farmacológicoRESUMO
Tafamidis, a non-nonsteroidal anti-inflammatory benzoxazole derivative, acts as a transthyretin (TTR) stabilizer to slow progression of TTR amyloidosis (ATTR). Tafamidis meglumine, available as 20-mg capsules, is approved in more than 40 countries worldwide for the treatment of adults with early-stage symptomatic ATTR polyneuropathy. This agent, administered as an 80-mg, once-daily dose (4 × 20-mg capsules), is approved in the United States, Japan, Canada, and Brazil for the treatment of hereditary and wild-type ATTR cardiomyopathy in adults. An alternative single solid oral dosage formulation (tafamidis 61-mg free acid capsules) was developed and introduced for patient convenience (approved in the United States, United Arab Emirates, and European Union). In this single-center, open-label, randomized, 2-period, 2-sequence, crossover, multiple-dose phase 1 study, the rate and extent of absorption were compared between tafamidis 61-mg free acid capsules (test) and tafamidis meglumine 80-mg (4 × 20-mg) capsules (reference) after 7 days of repeated oral dosing under fasted conditions in 30 healthy volunteers. Ratios of adjusted geometric means (90%CI) for the test/reference formulations were 102.3 (98.0-106.8) for area under the concentration-time profile over the dosing interval and 94.1 (89.1-99.4) for the maximum observed concentration, satisfying prespecified bioequivalence acceptance criteria (90%CI, 80-125). Both tafamidis regimens had an acceptable safety/tolerability profile in this population.
Assuntos
Neuropatias Amiloides/tratamento farmacológico , Benzoxazóis/farmacocinética , Cardiomiopatias/prevenção & controle , Pré-Albumina/efeitos dos fármacos , Administração Oral , Adulto , Neuropatias Amiloides Familiares/complicações , Benzoxazóis/administração & dosagem , Benzoxazóis/efeitos adversos , Brasil , Canadá , Cardiomiopatias/tratamento farmacológico , Cardiomiopatias/etiologia , Cardiomiopatias/genética , Estudos Cross-Over , Progressão da Doença , Relação Dose-Resposta a Droga , Esquema de Medicação , Composição de Medicamentos/métodos , Jejum/sangue , Feminino , Voluntários Saudáveis/estatística & dados numéricos , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Pré-Albumina/metabolismo , Segurança , Equivalência Terapêutica , Estados UnidosRESUMO
PURPOSE: Autonomic dysfunction is a very common, early and distressing aspect of hereditary transthyretin (ATTR) amyloidosis leading to significant loss of quality of life and morbidity for patients. Although the clinical variability of ATTR has been well characterized as neuropathic, cardiac or mixed phenotype, the extent of autonomic involvement remains poorly understood. Despite the fact that the autonomic nervous system has not been specifically evaluated in any of the clinical trials of tafamidis, and that, for some primary and secondary endpoints used in these trials, the behavior cannot be separated from non-autonomic items, an attempt was made to use published material to indirectly access the efficacy of tafamidis in treating dysautonomia. METHODS: Literature review summarizing the results of primary and secondary endpoints related to the autonomic features used in the original tafamidis trials, the post hoc publications, and real-world data, on the effect of tafamidis on autonomic dysfunction in patients with ATTR amyloidosis. RESULTS: There is some evidence that indirectly demonstrates that tafamidis is safe and could slow or arrest the progression of autonomic neuropathy in patients with ATTR amyloidosis, in addition to its well-described effects to ameliorate sensory-motor peripheral neuropathy. CONCLUSION: Although the current evidence is scarce, tafamidis might be effective in arresting the progression of autonomic neuropathy in patients with ATTR amyloidosis. Tafamidis might be more effective at the early stage of the disease; however, individual responses must be monitored.
Assuntos
Neuropatias Amiloides Familiares/complicações , Neuropatias Amiloides Familiares/tratamento farmacológico , Doenças do Sistema Nervoso Autônomo/tratamento farmacológico , Doenças do Sistema Nervoso Autônomo/etiologia , Benzoxazóis/uso terapêutico , Humanos , Polineuropatias/tratamento farmacológico , Polineuropatias/etiologiaRESUMO
Transthyretin (TTR)-related amyloidosis (ATTR) is a devastating disease which affects a combination of organs including the heart and the peripheral nerves, and which has a fatal outcome if not treated within a average of 10 years. Tafamidis, or 2-(3,5-dichloro-phenyl)-benzoxazole-6-carboxylic acid, selectively binds to TTR with negative cooperativity and kinetically stabilizes wild-type native TTR and mutant TTR; tafamidis therefore has the potential to halt the amyloidogenic cascade initiated by TTR tetramer dissociation, monomer misfolding, and aggregation. The first tafamidis trial, Fx-005, evaluated the effect of 18 months of tafamidis treatment (20 mg once daily) on disease progression, as well as assessing its safety in TTR-FAP Val30Met patients. The secondary objective of this trial was to study the pharmacodynamic stabilization of mutated TTR. Tafamidis proved effective in reducing the progress of neuropathy, and in maintaining the nutritional status and quality of life of stage 1 (able to walk without support) Val3OMet TTR-FAP patients. Furthermore, TTR stabilization was achieved in more than 90% of patients. An extension study, Fx-006, was conducted to determine the long-term safety and tolerability of tafamidis and to assess the efficacy of the drug on slowing disease progression. No significant safety or tolerability issues were noticed. Taken together, the results from both trials indicated that the beneficial effects of tafamidis were sustained over a 30-month period and that starting treatment early is desirable. Results are expected from an extended open-label study but data that have already been presented show that long-term use of tafamidis in Val30Met patients is associated with reduced progression in polyneuropathy. Tafamidis was initially approved for commercial use in Europe in 2011 and has since been approved for use in Japan, Mexico, and Argentina where it is used as a first-line treatment option for patients with early-stage TTR-FAP. Patients should be carefully followed at referral centers to ascertain the individual response to treatment. In cases of discontinuation, liver transplantation and enrollment in clinical trials of novel drugs aimed mostly toward suppression of TTR production are options.