On February 25-26, 2014, FDA will hold a meeting of the Cellular, Tissue, and Gene Therapies Advisory Committee. A majority of the meeting will concern oocyte modification in assisted reproduction for the prevention of transmission of mitochondrial disease or treatment of infertility. While FDA will post meeting materials at least two business days before the meeting, one item that will likely be discussed is a workshop held in September 2002 on Evidence Based Assisted Reproductive Technologies (ART) that concerned oocyte modification. Approximately half of the second day will focus on considerations for the design of early-phase clinical trials of cellular and gene therapy products, which was the topic of a revised guidance published on July 2, 2013. This meeting was originally scheduled for October 22-23, 2013 but was postponed “due to resource constraints arising from the government shutdown.”
The July Draft Guidance provided recommendations to assist in designing early-phase clinical trials of cellular therapy (“CT”) and gene therapy (“GT”) products, collectively referred to as “CGT products”, which covers most Phase 1 trials and some Phase 2 trials. FDA considers clinical study designs for CGT products to be different because of the way the products work and the potential for substantial risk. In the past, FDA halted CGT therapies due to experiences that included: (1) multiple-organ failure and death of a subject receiving a GT product for ornithine transcarbamylase deficiency, (2) late-onset T-cell leukemia in subjects who received a GT product for X-linked severe combined immunodeficiency, and (3) the development of tumors in the brain and spinal cord of a patient who received intrathecal allogenic stem cells for ataxia telangiectasia.
FDA’s Guidance on early-phase clinical trials explained that unlike many small molecule drugs, there is much less experience across a broad population with CGT products, leading to more uncertainty with clinical study design and controls. Some CGT products persists in humans for an extended time period and the administration may involve surgery or other invasive procedures that may require use of an investigational medical device. Allogenic CT products, GT vectors, and proteins that may be produced by CGT products have the potential to produce an immune response that may produce an unintended adverse reaction or sensitivity to a CGT product in the future. CGT products are cellular products and so mimic the complex, dynamic nature of living cells, which can migrate within the recipient’s body.