OBJECTIVES : To evaluate cost of inotersen and patisiran for treatment of adults with polyneuropathy of hereditary transthyretin-mediated amyloidosis in the Canadian, German, and Italian healthcare settings.

METHODS : Cost of treating amyloidosis patients with inotersen and patisiran was estimated based on drug utilization, over 1-year period from therapy initiation, and corresponding unit costs. Drug utilization was characterized—per prescribing information—based on number of administrations and dose per administration. Dose of inotersen was assumed to be 284 mg (subcutaneous injection), once weekly. Dose of patisiran was assumed to be 0.3 mg/kg (IV), every 3 weeks; patient body weight was estimated using country-specific clinical trial data. Unit costs for inotersen 284 mg syringe (Canada, CAD 8,077; Germany, EUR 5,396; Italy, EUR 5,980) and patisiran 10 mg vial (Canada, CAD 13,022; Germany, EUR 7,053; Italy, EUR 8,529) were based on public sources. One-year costs (2020 values) were expressed per 10 treated patients in each country; for patisiran, drug wastage was calculated as the remainder of opened, but not fully administered, vials.

RESULTS : Over the 1-year period from therapy initiation (per 10 patients), the number of inotersen administrations totaled 522 in each country and corresponding total cost was CAD 4.2M in Canada, EUR 2.8M in Germany, and EUR 3.1M in Italy. In contrast, the number of patisiran administrations totaled 174 in each country, and the total number of patisiran vials opened was 467 in Canada, 442 in Germany, and 442 in Italy. Total cost of patisiran was CAD 6.1M in Canada, EUR 3.1M in Germany, and EUR 3.8M in Italy, and 18-19% (Canada: CAD 1.1M; Germany: EUR 0.60M; Italy: EUR 0.73M) of costs were attributable to drug wasted.

CONCLUSIONS : Use of inotersen for the treatment of patients with polyneuropathy of hereditary transthyretin-mediated amyloidosis may yield lower drug costs than patisiran and no drug wastage.