Sobi Receives Approval from Health Canada for Once-Daily Dosing of Orfadin (nitisinone) for the Treatment of HT-1

Sobi has received approval from Health Canada for a reduced dosing frequency for Orfadin (nitisinone).

Orfadin is approved in combination with dietary restriction of tyrosine and phenylalanine in the treatment of hereditary tyrosinemia type 1 (HT-1), a rare genetic disorder that may result in liver, renal and neurological complications and in most cases is fatal if untreated. The once-daily reduced dosing frequency is approved for use in patients who weigh 20 kg or more and who have undetectable serum and urine succinylacetone concentrations after a minimum of 4 weeks on a stable twice-daily dosage of nitisinone.

“Orfadin is the first nitisinone product approved for once-daily use in Canada. This is an important step towards reducing the treatment burden of people with HT-1 and it follows Sobi’s introduction of Orfadin oral suspension and 20 mg capsules,” said Bob McLay, Vice President and General Manager of Sobi Canada, Inc. “In the U.S., where all Orfadin dosing and formulation options have been available for some time, we see patients increasingly choosing to take advantage of the flexibility that these options offer. I am glad to be able to offer these choices to patients in Canada as well.”

Sobi currently provides a range of Orfadin dosing options in Canada including 2mg, 5mg, 10mg, and 20mg capsules, as well as a 4mg/mL oral suspension and the new once-daily dosing frequency. The original Canadian approval of Orfadin was based on a multinational, uncontrolled, open-label study of 291 HT-1 patients. Patients treated with Orfadin and dietary restrictions experienced 2-, 4-, and 6-year survival probabilities of 93% to 96%; historical controls treated with dietary restriction alone experienced survival probabilities of 38% and 29% (1- and 2-year survival, respectively, for patients younger than 2 months of age at the onset of symptoms), 74% (for patients 2-6 months of age at the onset of symptoms), and 96% (for patients older than 6 months of age at the onset of symptoms). The most common reported adverse reactions in the trial were thrombocytopenia, leucopenia, granulocytopenia and conjunctivitis, corneal opacity, keratitis, and photophobia. No patients discontinued treatment due to adverse drug reactions. More information and the Product Monograph can be found at the Sobi North America website.

“HT-1 caregivers often feel their life is far from normal, revolving around the demanding treatment schedule and dietary restrictions, so I am grateful to Sobi for bringing new dosing options like once-daily Orfadin to Canada,” said Durhane Wong-Rieger, President of the Canadian Organization for Rare Disorders. “It is particularly important to have dosing options like this for patients approaching adolescence, as studies have shown that adherence to medicines is more difficult at this age.”