FDA approves Global Blood Therapeutics's sickle cell disease drug

Henrietta Strickland
November 29, 2019

It was approved in 2017 to be the first new sickle cell disease treatment in 20years.

Sickle cell disease is a lifelong, inherited blood disorder in which red blood cells are abnormally shaped (in a crescent, or "sickle" shape), which restricts the flow in blood vessels and limits oxygen delivery to the body's tissues, leading to severe pain and organ damage. We are proud to bring this breakthrough therapy to the SCD community.

The treatment will be priced at $10,417 per month, or around $125,000 per year, and will be sold under the brand name Oxbryta.

About half of the patients the company expects to treat with Oxbryta are covered by Medicaid, and another 15% are covered by Medicare, GBT executives said.

The approval is based on the results of the HOPE trial, which found that Oxbryta was able to achieve an increase in the haemoglobin response rate - defined as an increase of at least one gram per decilitre after 24 weeks - compared to placebo.

Patients were randomly assigned to receive a once-daily oral dose of 1500 mg voxelotor, 900 mg of voxelotor, or placebo. Voxelotor-treated patients also had better percent change in indirect bilirubin (-29.08% vs. -3.16%, respectively) and percent reticulocyte count (-19.93% vs. 4.54%, respectively) compared with placebo.

Benefits were seen regardless of concurrent use of hydroxyurea, a standard treatment to reduce the frequency of pain crises and the need for blood transfusions.

Overall, the percentage of patients with an adverse event that occurred or worsened during the treatment period was similar across the trial groups, according to the study.

Today is a major milestone not only for GBT but, most importantly, for people living with SCD, their families and those who care for them. Nonclinical studies demonstrated that voxelotor inhibits red blood cell sickling, improves red blood cell deformability and improves the blood's ability to flow.

"Oxbryta is an inhibitor of deoxygenated sickle hemoglobin polymerization, which is the central abnormality in sickle cell disease", Richard Pazdur, MD, director of the FDA's Oncology Center of Excellence, said in an agency release. We are grateful to the patients, caregivers, clinical trial investigators, healthcare providers and advocates who have worked alongside us to develop this first-in-class therapy.

Common side effects for patients taking Oxbryta were headache, diarrhea, abdominal pain, nausea, fatigue, rash and pyrexia (fever).

Following behind the new drug treatments for CD are gene therapies that promise to deliver a one-shot treatment for the disease.

Margarida graduated with a BS in Health Sciences from the University of Lisbon and a MSc in Biotechnology from Instituto Superior Técnico (IST-UL).

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