CSL doses first patient with haemophilia B gene therapy Hemgenix

CSL announced the first patient with haemophilia B has been treated with its recently approved gene therapy Hemgenix (etranacogene dezaparvovec).

Hemgenix is the first and only gene therapy approved for haemophilia B. At $3.5m per dose, it is the most expensive single-use gene therapy in the US. The high price tag may be hard to defend, but with lifetime treatment costs for haemophilia B reaching as high as $23m for some, the single-dose treatment could prove far more cost-effective. Despite this, the Institute for Clinical and Economic Review (ICER) claimed that a fairer price would be in the region of $2.9m.

In the past year, Hemgenix has been granted approval by the US Food and Drug Administration (FDA) and has received conditional marketing authorisation from the European Commission (EC) and the UK’s Medicines and Healthcare products Regulatory Agency (MHRA). This followed positive results from CSL’s Phase III HOPE-B trial (NCT03569891). In the study, Hemgenix reduced or eliminated the need for prophylactic treatment in 94% of patients.

In a 20 June press release, CSL Behring’s North America general manager and senior vice-president Bob Lojewski said that the company was “thrilled” by this latest milestone and looked forward to more patients benefitting from the therapy.

Hemgenix works by dosing a patient with an engineered adeno-associated virus (AAV), containing the gene responsible for producing a protein called factor IX. This protein helps to form blood clots and stop bleeding, with haemophilia B arising when the body is partially or completely unable to produce it. Once administered, the body will then be able to produce factor IX and prevent severe bleeds.

Already a big player in haemophilia treatments, CSL licensed exclusive global rights to Hemgenix from gene therapy developers uniQure back in 2021. UniQure announced that it had received $100m from this first commercial sale milestone, on top of a $450m upfront payment. It is eligible for up to $1.6bn based on future milestones, as well as royalties amounting to more than 20% of net product sales.

Haemophilia B is a rare condition. It predominantly affects males, with the CDC estimating 33,000 cases in males across the US. Despite the limited market, the price tags of haemophilia make it potentially lucrative.

GlobalData forecasts predict that the global market for haemophilia A and haemophilia B treatments will grow to $14.7bn by 2030, up from $9.3bn in 2020 – an annual growth of nearly 5%. Gene therapies have long been predicted as the next big thing in haemophilia treatment, and are likely to drive this growth.

GlobalData is the parent company of Pharmaceutical Technology.

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