Sickle Cell Therapy Safety Assessment Questioned

Share

FDA reviewers will ask an advisory committee 10/31 whether Vertex Pharmaceuticals and CRISPR Therapeutics need to conduct additional studies on their sickle cell disease (SCD) gene therapy exagamglogene autotemcel (exa-cel) to obtain a better safety assessment.

According to briefing documents released 10/27 in advance of the meeting, reviewers are seeking input on “whether the off-target analysis (e.g., in silico and cellular methods)” performed by the companies is adequate to assess risk in the intended SCD patient population in the U.S. The reviewers further noted that it was “not clear if the limited SCD donor cells used for the off-target assessment will adequately inform the potential safety risks of exa-cel.”

The reviewers emphasized the current “unmet need” from current available treatments for SCD, which include hydroxyurea, L-glutamine, voxelotor, and crizanlizumab. The disease is associated with vaso-occlusive crises, “which most commonly are severe painful events, but may also present with acute chest syndrome, priapism, or hepatic/splenic sequestration,” they write. “In the longer term, SCD may lead to life-threatening neurologic, pulmonary, cardiac, and renal complications and a shortened life span (survival).”

Read more