Global Blood Therapeutics sells one drug that treats sickle cell disease and it’s developing another one that could offer a different treatment approach. The company is spreading its bets even further with the acquisition of two Sanofi compounds that could offer other ways to treat the rare disorder.
According to deal terms announced Tuesday, GBT is responsible for conducting all research, development, and regulatory work for the drugs, which come from Sanofi’s Bioverativ subsidiary. If they are approved, the biotech is also responsible for their commercialization globally.
GBT is committing to pay Sanofi up to $353 million for the rights to the two small molecules. The announcement did not specify how that payment breaks down but a securities filing from South San Francisco-based GBT shows it agreed to pay $2.25 million up front and up to $351 million tied to the achievement of regulatory, commercial, and sales milestones.
Sanofi would also receive royalties from sales if GBT is able to bring one or both drugs to the market. But for the France-based pharma giant, offloading the two small molecules is a sign that the company is choosing to focus its sickle cell efforts on a gene-editing treatment in development with partner Sangamo Therapeutics.
Sickle cell disease is an inherited disorder in which hemoglobin, the blood protein that carries oxygen, abnormally forms into a crescent shape. That shape can block capillaries and small blood vessels, leading to organ damage and other complications throughout the body.
Oxbryta is designed to block hemoglobin polymerization, the process that causes red blood cells to become sickle shaped. Approved by the FDA in 2019, it’s the only sickle cell treatment drug that works in this manner and is GBT’s only commercialized product. In 2020, Oxbryta accounted for $123.9 million in sales, according to the company’s report of 2020 financial results.
The next GBT drug in the pipeline is inclacumab, an antibody designed to target P-selectin, a target in sickle cell disease that is known to reduce the incidence of vaso-occlusive crisis, a painful complication of the disorder. GBT licensed the drug from Roche in 2018. The biotech is also working on a “next-generation” version of Oxbryta that could offer better therapeutic effects but at lower doses. That drug, GBT601, started a Phase 1 study late last year.
The two Sanofi compounds GBT is acquiring each take different approaches to sickle cell disease. One uses a “novel anti-sickling mechanism” while the other is intended to reduce inflammation and oxidative stress, according to the company. GBT has said its strategy is to develop multiple approaches to treating sickle cell disease. Oxbryta is a once-daily pill that patients must take for life and the other drugs the biotech is developing will also likely require patients to take them on a regular basis.
“We envision a future in which sickle cell disease is a well-managed condition with the potential for a functional cure in the form of patient-friendly oral therapies,” Jung Choi, chief business and strategy officer of GBT said in a prepared statement.
But other companies are in clinical development with therapies that offer the prospect of a one-time treatment that is long-lasting, if not permanent. Bluebird bio has reached human testing of a gene therapy for the disorder, though the Cambridge, Massachusetts-based company’s clinical trials remain under FDA clinical holds after two suspected cases of cancer were reported in the studies.
Sanofi’s partnership with Brisbane, California-based Sangamo uses that company’s zinc finger nuclease technology to edit a patient’s stem cells so that they produce fetal hemoglobin. This fetal hemoglobin is hoped to provide a patient with functional versions of that key blood protein. A Phase 1 study testing the gene-editing treatment, BIVV003, is underway. Sanofi inherited this alliance via its 2018 acquisition of Bioverativ. Sangamo said in its 2020 annual report that it expects Phase 1 data will be available by the end of 2021.
Vertex Pharmaceuticals and CRISPR Therapeutics are further ahead in clinical development of a gene-editing therapy for sickle cell disease. Last December, encouraging data from an ongoing Phase 1/2 study were reported at the annual meeting of the American Society of Hematology. Peer-reviewed data were also published in the New England Journal of Medicine.
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