MOST EXPENSIVE DRUGS

Leading that pack at number 1 is glycerol phenylbutyrate (Ravicti, Horizon Pharma), an orphan drug approved by the US Food and Drug Administration (FDA) in 2013 for the long-term management of urea cycle disorders, which are estimated to affect 1 in 8500 births. The list price per year for Ravicti is about $793,000, according to the analysis compiled by Endpoints News. But a spokesperson for Horizon Pharma told Medscape Medical News that the accurate list price for Ravicti is approximately $556,000 per year, which would put it lower on the list.

Taking the number 2 spot on the list is orphan drug cerliponase alfa (Brineura, BioMarin International Ltd), approved last month by the FDA for the treatment of infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease, a form of Batten disease. The drug will cost an estimated $702,000 a year. About 20 new cases of CLN2 are diagnosed each year.

Coming in at number 3 is alglucosidase alfa (Lumizyme, Sanofi-Genzyme), approvedin 2010 to treat late-onset Pompe disease in children aged 8 years and older. It has a list price of about $626,400 per year, according to the analysis.

Orphan drug carglumic acid (Carbaglu, Recordati), for treating the rare genetic disorder N-acetylglutamate synthase deficiency, which causes hyperammonemia, holds the number 4 spot on the list of most expensive drugs. The drug was approvedin 2010 and has a list price of about $585,400 per year.

Number 5 on the list is interferon gamma 1-b (Actimmune, Horizon Pharma), approved to decrease the number and severity of infections in patients with chronic granulomatous disease and to delay the progression of severe, malignant osteopetrosis. The list price tops $572,000 annually, according to the analysis. However, Horizon Pharma said the accurate list price for Actimmune is approximately $480,000/year.

Rounding out the top 10 most expensive drugs are the following: 

6. Eculizumab (Soliris, Alexion Pharmaceuticals), approved for paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. It has an estimated list price of $542,640 per year.

7. Coagulation factor IX recombinant Fc fusion protein (Alprolix, Bioverativ), the first long-acting hemophilia B drug approved by the FDA for use in children and adults with hemophilia B. It has a list price of about $503,800 per year.

8. Albutrepenonacog alfa (Idelvion, CSL Behring), another long-acting hemophilia B drug. Approved in 2016, Idelvion combines albumin with factor IX to reduce injection frequency. It has an annual price tag of $500,000.

9. Galsulfase (Naglazyme, Biomarin Phamaceutical), approved in 2005 to improve walking and stair-climbing capacity of patients with mucopolysaccharidosis VI. It lists for around $485,700 per year.

10. Pralatrexate (Folotyn, Spectrum Pharmaceuticals) was approved in 2009 to treat relapsed or refractory peripheral T-cell lymphoma. The relatively rare and often aggressive type of non-Hodgkin's lymphoma occurs in fewer than 9500 US patients annually. Folotyn has a list price of around $450,500.