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Aug 13 2019

A Platform for Screening Drugs to Treat Sickle Cell Disease

SEATTLE, August 13, 2019  -- ReachBio Research Labs (trade name under ReachBio LLC), a CRO specializing in primary cell assay services and products, is now offering a drug screening platform to assess HbF (fetal hemoglobin) protein induction in drug candidates to treat sickle cell disease as well as other hemoglobinopathies such as β-thalassemias.

Hemoglobinopathies, including β-thalassemias and sickle cell disease, are a group of inherited blood disorders, most of which arise from mutations in the β-globin gene that encodes the β-subunit of hemoglobin. β-thalassemia is characterized by a reduction in the production of adult hemoglobin (HbA) which can result in severe anemia. In instances where sickle cell disease occurs, the HbA produced is abnormal, causing the red blood cells to stiffen and adopt the ‘sickle’ morphology causing, in many cases, severe anemia and acute pain.

Clinical severity of these diseases can be reduced by enhancing expression of the γ-globin gene (HBG) that encodes the γ-subunit of HbF, which is the main oxygen transport protein in the fetus, and has a higher affinity for oxygen than HbA. HbF constitutes the major hemoglobin during fetal life, gradually replaced by adult hemoglobin (HbA) during infancy. However, adults do retain low levels of HbF expression (~ 0.1 – 1% total hemoglobin). 

The FDA approved drug hydroxyurea (HU) is the current standard of care for the treatment of sickle cell disease. It increases HbF levels, despite incomplete knowledge on mechanism, but has had very limited success in treating β-thalassemia, where only minor elevations in HbF is achieved. Coupled with the statistic that 30-50% patients affected by sickle cell disease are unresponsive to HU treatment, the need for better performing drug candidates remains high.     

ReachBio’s new drug screening platform is a serum-free cell culture system where unaffected primary human bone marrow cells can be expanded in the presence of various cytokines. There are two stages, in the initial stage cells are synchronized and in the second stage a media change occurs with aims to induce significant differentiation along the erythroid (red blood cell) lineage. The addition of HU to this assay consistently induces HbF.  

Dr. Emer Clarke, Chief Scientific Officer at ReachBio Research Labs, mentions, ‘One of the advantages of this platform is that it ‘directly’ measures the actual HbF protein as opposed to other approaches that look at increases in transcript numbers or other indirect measurements which may not correlate directly with HbF protein levels. Furthermore, this high-throughput in vitro HbF induction assay will facilitate the ability to examine many new potential drug therapies, both alone and in combination with HU.’ 

Rob Chaney, General Manager & Chief Operations Officer at ReachBio Research Labs, adds, ‘New drug approvals to address sickle cell disease symptoms have been scarce over the last 20 or so years.   However, drug development companies and academic researchers are starting to make progress on this front due to the FDA’s mandate to excel development for new treatments. 

To attract companies to develop promising new sickle cell disease treatments, the FDA is supporting ‘fast track’ designation to bring new products to market faster, as well as giving certain drugs ‘orphan status’ for rare diseases. We believe this combined effort is generating progress as we now have clients inquiring about sickle cell disease drug screening assays which was a less frequent topic of conversation just a year ago.  We are excited to be able to address our clients’ drug development challenges with our new high-throughput screening platform.’