Graphite Bio, Inc. announced it is voluntarily pausing the Phase 1/2 CEDAR study of nulabeglogene autogedtemcel (nula-cel) for sickle cell disease (SCD) due to a serious adverse event in the first patient dosed with nula-cel, and the company's conclusion that the event is likely related to study treatment. As a result, the company will not meet its guidance for initial proof-of-concept data in mid-2023. The decision by Graphite Bio to voluntarily pause the CEDAR study follows a serious and unexpected adverse event of prolonged low blood cell counts (pancytopenia) requiring ongoing transfusion and growth factor support in the first patient dosed with nula-cel.

The event has been reported to the U.S. Food and Drug Administration. The patient achieved study-defined neutrophil engraftment and has shown no evidence of myelodysplasia, a rare type of blood cancer. While the event did not meet study stopping requirements, based on evolving clinical data, Graphite Bio decided to voluntarily pause the study.

Graphite Bio is comprehensively assessing the adverse event, risk factors and mitigation strategies, including potential modifications to the nula-cel manufacturing process. The clinical investigators and Safety Monitoring Committee for the CEDAR study have agreed with the company's decision to suspend dosing of additional patients pending this assessment. Based on the ongoing activities in the nula-cel program, Graphite Bio no longer expects to file an investigational new drug application for GPH102 in beta-thalassemia by mid-2024.

The company is also working to identify operational efficiencies to extend its cash position to at least 2026. Graphite Bio will provide a business update by the end of the first quarter of 2023. Nula-cel, formerly GPH101, is an investigational next-generation gene editing autologous hematopoietic stem cell (HSC) therapy designed to directly correct the genetic mutation that causes sickle cell disease (SCD).

A serious, life-threatening inherited blood disorder, SCD affects approximately 100,000 people in the United States and millions of people around the world, making it the most prevalent monogenic blood disease worldwide. Nula-cel is the first investigational therapy to use a highly differentiated gene correction approach that seeks to efficiently and precisely correct the mutation in the beta-globin gene to decrease sickle hemoglobin (HbS).