Regulators hit the brakes on a gene-editing therapy train before it even left the station.
CRISPR Therapeutics and Vertex Pharmaceuticals said Wednesday that the Food and Drug Administration placed a clinical hold on their application to start a clinical trial of their CRISPR gene-editing therapy, CTX001, for sickle cell disease. The hold was placed “pending the resolution of certain questions that will be provided by the FDA as part of its review” of the investigational new drug application, or IND. The companies are headquartered in Zug, Switzerland, and Boston, respectively.
The companies said they expected to obtain additional information on the FDA’s questions in the near future and work toward a resolution, but they did not provide further details. The IND was submitted in April to support the Phase I/II study. At the same time, a planned Phase I/II study of CTX001 in beta-thalassemia remains on track and will be initiated in the second half of this year.
With the therapy, sickle cell disease and beta-thalassemia patients’ cells are engineered outside the body to produce high levels of fetal hemoglobin, or HbF, in red blood cells. The aim is that elevating HbF will alleviate the blood transfusions on which beta-thalassemia patients depend while also alleviating painful and debilitating sickle crises in sickle cell disease patients.
Both diseases are key targets for gene therapy. Cambridge, Massachusetts-based bluebird bio is developing the gene therapy LentiGlobin for sickle cell disease and beta-thalassemia. However, LentiGlobin is a viral vector-based gene therapy, whereby specially engineered viruses are used to transfect cells and change their genes, rather than one that uses gene editing techniques like CRISPR. Other gene-editing technologies include TALENs and zinc finger nucleases.
Other companies using CRISPR to develop medicines include Editas Medicine and Beam Therapeutics – both based in Cambridge – and Berkeley, California-based Caribou Biosciences. The market for gene therapies is expected to reach $363 million by 2022, according to a report by Market Reports Center, though the report defined gene therapy to also include CAR-T cell therapies and oncolytic viral therapies for cancers.
A Deep-dive Into Specialty Pharma
A specialty drug is a class of prescription medications used to treat complex, chronic or rare medical conditions. Although this classification was originally intended to define the treatment of rare, also termed “orphan” diseases, affecting fewer than 200,000 people in the US, more recently, specialty drugs have emerged as the cornerstone of treatment for chronic and complex diseases such as cancer, autoimmune conditions, diabetes, hepatitis C, and HIV/AIDS.
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