US regulators approve GBT's haemoglobin polymerisation inhibitor Oxbryta for sickle cell disease

Global Blood Therapeutics announced Monday that the FDA has granted accelerated approval to its marketing application for Oxbryta (voxelotor) to treat sickle cell disease (SCD) in adults and children 12 years of age and older. According to the company, the once-daily oral therapy is the first approved treatment that directly inhibits sickle haemoglobin polymerisation, the root cause of SCD. 

Oxbryta will carry a list price of $125,000 a year, though GBT said the drug would cost most health plans $96,000 a year after discounts. About half of the patients the company expects to treat with Oxbryta are covered by Medicaid, and another 15% are covered by Medicare, noted GBT chief executive Ted Love. The treatment is expected to be available through GBT’s specialty pharmacy partner network within two weeks.

The FDA approval was based on results from the 274-patient Phase III HOPE trial, demonstrating "significant and sustained improvements" in haemoglobin with Oxbryta, compared to placebo. Specifically, 51.1% of patients given the higher dose of the drug achieved a greater than 1 g/dL increase in haemoglobin after 24 weeks of treatment, compared with 6.5% for placebo. 

According to Richard Pazdur, acting director of the Office of Oncologic Diseases in the FDA's Center for Drug Evaluation and Research, "with Oxbryta, sickle cells are less likely to bind together and form the sickle shape, which can cause low haemoglobin levels due to red blood cell destruction." 

Earlier this month, the US regulator cleared Novartis' anti-P-selectin antibody Adakveo (crizanlizumab) to reduce the frequency of vaso-occlusive crises in SCD patients aged 16 years and older. The price for that drug has been set between $84,852 and $113,136 per year for most patients. 

For related analysis, see ViewPoints: Does SCD offer another blockbuster shot for Novartis?   


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