Tafamidis for the treatment of transthyretin amyloidosis

A retrospective observational analysis of the real-world care pathway of people with hereditary transthyretin amyloidosis with polyneuropathy in Italy

BACKGROUND

This retrospective observational study described the epidemiology and the burden on the Italian healthcare service (SSN) of patients with polyneuropathy (PN) associated with hereditary transthyretin amyloidosis (ATTRv).

RESEARCH DESIGN AND METHODS

From the Fondazione ReS (Ricerca e Salute) administrative healthcare database (~5.5 million inhabitants in 2021), patients were identified as having ATTRv-PN in 2021 if they had received treatments for ATTRv-PN under SSN reimbursement (i.e. tafamidis, patisiran, or inotersen) from 1 January 2014 to 31 December 2021 (index date in 2021). Demographics and comorbidities at the baseline, healthcare resource consumption, and related direct costs reimbursed by the SSN throughout the one-year follow-up were described.

RESULTS

In 2021, 36 patients with ATTRv-PN (prevalence: 7.4/1,000,000) were identified (males were 83.3%; patients with ≥2 comorbidities were 61.1%; the mean age was 73 ± 8 years). During follow-up, of patients, 91.7% received drugs for ATTRv-PN; >50% received antiepileptics and acid suppressants; 22.2% were admitted to overnight hospitalizations; 30.6% accessed the emergency department; 97.2% received local outpatient specialist care. The per patient mean annual cost was € 122,017; drugs for ATTRv-PN accounted for 94.7% of the total expenditure.

CONCLUSIONS

This study of real-world patients with ATTRv-PN showed a high rate of comorbidities, and substantial direct healthcare and economic burdens on the SSN.

Analysis of post-market adverse events of tafamidis base on the FDA adverse event reporting system

Tafamidis is the world's first and only oral drug approved to treat the rare disease transthyretin amyloid cardiomyopathy (ATTR-CM). Medicines are known to have different adverse reactions during the course of treatment. However, the current limited clinical studies did not identify significant adverse drug reactions to tafamidis. Tafamidis has been on the market for 5 years now, a large number of adverse drug event (ADE) reports with tafamidis as the primary suspected drug have been reported in the United Food and Drug Administration's adverse event reporting system (FAERS). We retrieved 8170 adverse event reports in FAERS with tafamidis as the first suspected drug, and mined these reports for positive signals to perform risk warnings for potentially possible adverse events with tafamidis. We found that a large number of adverse events associated with the primary disease were reported due to insufficient awareness of ATTR among the reporters, leading to a large number of positive signals reported in the cardiac disorders system. We also found that tafamidis has the potential to cause an adverse event risks of ear and labyrinth disorders system and urinary tract infection bacterial, which deserve continued clinical attention.

The Bioequivalence of Tafamidis 61-mg Free Acid Capsules and Tafamidis Meglumine 4 × 20-mg Capsules in Healthy Volunteers

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.