Nov 22 (Reuters) - Australian drugmaker CSL Ltd (CSL.AX) on Tuesday set the list price of its one-time gene therapy for hemophilia B at $3.5 million, making it the world's most expensive treatment, following its approval by the U.S. health regulator. The first gene therapy for the rare genetic blood clotting disorder offers a long-term solution for patients as against current treatments from Biogen (BIIB.O), Pfizer (PFE.N) and others that focus on regular infusions. The gene therapy consists of an engineered virus carrying a gene expressed in the liver to produce clotting factor IX. While Zynteglo was priced at $2.8 million, Skysona had a wholesale cost of $3.0 million. CSL shares were up 1% at A$300.62 on the Australian stock exchange, while UniQure stock edged up 0.9% in extended trading.

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