Regulatory Framework for Academic Investigator-Sponsored Investigational New Drug Development of Cell and Gene Therapies in the USA.

PURPOSE OF REVIEW: The promise of cell and gene therapy (CGT) products for a multitude of diseases has revitalized investigators to advance novel CGT product candidates to first-in-human trials by pursuing the investigational new drug (IND) mechanism administered by the United States (US) Food and Drug Administration (FDA). This review is intended to familiarize academic investigators with the IND governing regulations set forth by the FDA. RECENT FINDINGS: CGT products are extraordinarily complex biologics and, therefore, early-stage evaluation programs must be customized to satisfactorily address their unique developmental challenges. The US FDA continues to foster the development of transformational technology that will facilitate the broad application of safe and effective gene therapy products that have the potential to alleviate many conditions previously out of reach of therapeutic intervention. FDA is committed to working with the scientific community and industry to facilitate the availability of these treatments to patients. SUMMARY: The pathway to meet regulatory compliance during early stage IND programs can be daunting to academic investigators interested in CGT product development that typically don't progress beyond phase 1/2. However, by keeping abreast of current regulatory framework and building upon FDA's supportive infrastructure, an investigator can be well-positioned to advance innovative scientific discoveries towards early stage clinical assessments.

Preparation of intravenous cholesterol tracer using current good manufacturing practices.

Studies of human reverse cholesterol transport require intravenous infusion of cholesterol tracers. Because insoluble lipids may pose risk and because it is desirable to have consistent doses of defined composition available over many months, we investigated the manufacture of cholesterol tracer under current good manufacturing practice (CGMP) conditions appropriate for phase 1 investigation. Cholesterol tracer was prepared by sterile admixture of unlabeled cholesterol or cholesterol-d7 in ethanol with 20% Intralipid(®). The resulting material was filtered through a 1.2 micron particulate filter, stored at 4°C, and tested at time 0, 1.5, 3, 6, and 9 months for sterility, pyrogenicity, autoxidation, and particle size and aggregation. The limiting factor for stability was a rise in thiobarbituric acid-reacting substances of 9.6-fold over 9 months (P < 0.01). The emulsion was stable with the Z-average intensity-weighted mean droplet diameter remaining at 60 nm over 23 months. The zeta potential (a measure of negative surface charge protecting from aggregation) was unchanged at -36.2. Rapid cholesterol pool size was 25.3 ± 1.3 g. Intravenous cholesterol tracer was stable at 4°C for 9 months postproduction. CGMP manufacturing methods can be achieved in the academic setting and need to be considered for critical components of future metabolic studies.

Design and production of retro- and lentiviral vectors for gene expression in hematopoietic cells.

Successful retroviral gene transfer into hematopoietic cells has been demonstrated in a number of small and large animal models and clinical trials. However, severe adverse events related to insertional muta-genesis in a recent clinical trial for X-linked severe combined immunodeficiency reinforced the need to develop novel retroviral vectors with improved biosafety. Improvements include the use of self-inactivating (SIN) vectors as well as improvements in vector design. This chapter describes the basic design of gamma-retroviral and lentiviral SIN vectors that utilize a split-packaging system and includes a description of the various cloning modules frequently used in the design of such vectors that impact biosafety, titer, and transgene expression. In addition, this chapter describes the methods used for high titer vector production using calcium phosphate transfection both at research scale and at large scale for clinical application using a closed system bioreactor.