U.S. FDA’s team of reviewers has requested that the regulatory advisory panel assess the requirement for additional studies on the sickle cell disease gene therapy developed by Vertex Pharmaceuticals and CRISPR Therapeutics.
The U.S. Food and Drug Administration’s team of reviewers has requested that the regulatory advisory panel assess the requirement for additional studies on the sickle cell disease gene therapy developed by Vertex Pharmaceuticals and CRISPR Therapeutics.
The sickle cell gene therapy, named exagamglogene autotemcel or exa-cel, utilizes cutting-edge CRISPR gene editing technology and marks the first of its kind to reach the FDA’s approval consideration.
The FDA reviewers have expressed concerns regarding the potential for “off-target” unintended genomic modifications associated with this form of gene editing, which could potentially lead to other side effects. Notably, they did not raise any apprehensions about the therapy’s effectiveness.
However, the reviewers have noted that the limited genetic sample size utilized in the therapy’s laboratory analysis may not be adequate for a comprehensive safety assessment, as it did not encompass the diversity of the entire U.S. population affected by sickle cell disease.
Furthermore, they pointed out that it remains uncertain whether the analysis conducted by the company to evaluate the off-target risk was sufficiently robust.
According to RBC analyst Luca Issi, the FDA’s primary focus appears to be on the technological risks. He suggests that the FDA’s concerns seem manageable and anticipates that additional studies, if required, will be conducted after the therapy receives approval.
Vertex and CRISPR Therapeutics are seeking FDA approval for this groundbreaking therapy designed to address the inherited red-blood-cell disorder, which leads to an abnormal sickle-shaped deformation of the cells due to irregular hemoglobin levels.
If granted approval, the therapy could potentially provide patients with a one-time treatment option, as opposed to the necessity of frequent blood transfusions or the daily administration of drugs, such as Pfizer’s Oxbryta.
An independent panel is scheduled to convene on Tuesday to deliberate on the off-target analysis and determine the necessity for additional laboratory studies.
The FDA is slated to make a decision regarding the therapy’s use in patients aged 12 years and older by December 8.