Transthyretin hereditary amyloid polyneuropathy, also traditionally known as transthyretin familial amyloid polyneuropathy (ATTR-FAP), is a rare, relentless, fatal hereditary disorder. Tafamidis, an oral, non-NSAID, highly specific transthyretin stabilizer, demonstrated safety and efficacy in slowing neuropathy progression in early-stage ATTRV30M-FAP in a 1.5-year, randomized, double-blind, placebo-controlled trial, and 1-year open-label extension study, with a second long-term open-label extension study ongoing. Subgroup analysis of the effectiveness of tafamidis in the pivotal study and its open-label extensions revealed a relatively cohesive cohort of patients with mild neuropathy (i.e. Neuropathy Impairment Score for Lower Limbs [NIS-LL] ≤ 10) at the start of active treatment. Early treatment with tafamidis for up to 5.5 years (≥1 dose of tafamidis meglumine 20 mg once daily during the original trial or after switching from placebo in its extension) resulted in sustained delay in neurologic progression and long-term preservation of nutritional status in this cohort. Mean (95% CI) changes from baseline in NIS-LL and mBMI were 5.3 (1.6, 9.1) points and -7.8 (-44.3, 28.8) kg/m2 × g/L at 5.5 years, respectively. No new safety issues or side effects were identified. These data represent the longest prospective evaluation of tafamidis to date, confirm a favorable safety profile, and underscore the long-term benefits of early intervention with tafamidis.
Keywords: ATTRV30M; Amyloidosis; TTR Val30Met; disease modification; transthyretin amyloidosis.