Hematology Xagena

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Once-weekly prophylactic dosing in children: Alprolix meets primary endpoint and achieves low bleeding rates

Positive top-line results of the Kids B-LONG phase 3 clinical study that evaluated the safety, efficacy and pharmacokinetics of Alprolix [ Coagulation Factor IX ( Recombinant ), Fc Fusion Protein ] in children under age 12 with severe haemophilia B, were presented.
Alprolix was generally well tolerated and no inhibitors ( neutralising antibodies that may interfere with the activity of the therapy ) were detected during the study.
In this study, once-weekly prophylactic dosing with Alprolix resulted in low bleeding rates.
Alprolix is the only approved hemophilia B therapy with prolonged circulation in the body.

Kids B-LONG investigated the safety, efficacy, and pharmacokinetics of Alprolix in previously treated children under age 12 with severe haemophilia B.
The study's primary endpoint was to evaluate the occurrence of inhibitor development. Secondary endpoints included the overall and spontaneous annualised bleeding rates ( ABR ), which is the estimated number of yearly bleeding episodes, and the number of injections used to treat bleeding episodes.
In the study, children treated prophylactically with Alprolix had an overall median ABR of 1.97. The median ABR for spontaneous joint bleeds was zero.
Approximately 33% of participants in the study experienced zero bleeding episodes.
Overall, 91.7% of bleeding episodes were controlled by one or two injections of Alprolix.
The terminal half-life of Alprolix in the study was 66.5 hours for children under six and 70.3 hours for children six to less than 12 years of age.

No inhibitors to Alprolix were detected during the study. Alprolix was generally well tolerated and no cases of serious allergic reactions or vascular thrombotic events were reported in any participants, all of whom had been previously treated with other commercially available factor IX products.
No serious adverse events were determined by any investigator to be related to the drug. One adverse event, decreased appetite, was considered related to Alprolix treatment and was reported in one participant.
No participant discontinued the study due to an adverse event after receiving Alprolix.
The pattern of treatment-emergent adverse events reported was consistent with the population studied and generally consistent with results seen in adolescents and adults in the pivotal phase 3 B-LONG study.

Kids B-LONG was a global, open-label, multicenter study involving 30 boys with severe haemophilia B (f actor IX activity equal to or less than 2 IU per dL, or 2% ) with at least 50 prior exposure days to factor IX therapies.
The study was conducted at 16 haemophilia treatment Centers in six countries.
Overall, 27 participants ( 90% ) completed the study.
The median time participants spent in the study was 49.4 weeks, and 24 participants received Alprolix injections on at least 50 separate days ( exposure days ).

In the United States, Alprolix is indicated for the control and prevention of bleeding episodes, perioperative management and routine prophylaxis in adults and children with hemophilia B.
Alprolix is not indicated for immune tolerance induction therapy, which is a treatment for people with inhibitors, and should not be used in individuals with a known history of allergic reactions to Alprolix or any of the other ingredients in Alprolix.

Alprolix was developed by fusing factor IX to the Fc portion of immunoglobulin G subclass 1, or IgG1 ( a protein commonly found in the body ). It is believed that this enables Alprolix to use a naturally occurring pathway to prolong the time the therapy remains in the body.

Common adverse reactions ( incidence of greater than or equal to 1% ) from the B-LONG study were headache and oral paresthesia ( an abnormal sensation in the mouth ).

Haemophilia B occurs in about one in 25,000 male births annually, and more rarely in females, affecting about 6,300 people in the United States.
The World Federation of Hemophilia global survey conducted in 2012 estimates that approximately 28,000 people are currently diagnosed with haemophilia B worldwide.
It is caused by having substantially reduced or no factor IX activity, which is needed for normal blood clotting. People with haemophilia B experience bleeding episodes that cause pain, irreversible joint damage and life-threatening haemorrhages. Prophylactic injections of factor IX temporarily replace clotting factors necessary to control bleeding and prevent new bleeding episodes. ( Xagena )

Source: Swedish Orphan Biovitrum AB ( SOBI ), 2015