Geron announced yesterday that it has began the first clinical trial of human embryonic stem cells. The primary objective of this Phase I study is to assess the safety and tolerability of the stem cells. However, instead of using healthy objects like in a typical Phase I trial, this study is conducted with patients who have suffered from what's called a complete thoracic spinal cord injury.
According to CNN, the FDA first approved the trial in January 2009, but later required further research before the study could proceed. The FDA gave final approval in July of this year.
Stem cells are cells that have the ability to divide and develop into many different cell types in the body during early life and growth. When a stem cell divides, each new cell has the potential either to remain a stem cell or to become another type of cell with a more specialized function, such as a nerve cell, a skin cell, or a red blood cell.
Information about the trial is thin on the FDA's website, as expected. However, the FDA did publish this PowerPoint presentation, which shed some light on the safety issues the agency was focusing on. Among them is the ability to predict inappropriate differentiation / tumorigenicity of the injected cells.
As discussed stem cells can differentiate into different type of cells, including cancer cells. Because we still don't know how the body regulates this differentiation process, it is not surprising that the FDA is particularly interested in how Geron would track the injected cells and monitor the differentiation process.
