Regulatory Decision Strategy for Entry of a Novel Biologic Therapeutic with a Clinically Unmonitorable Toxicity into Clinical Trials: Pre-IND Meetings and a Case Example

Abstract

The following material was derived from a synthesis of case histories taken from investigational new drug (IND) applications and drug sponsors' experiences, utilizing fictionalized data to avoid any resemblance to any proprietary information; any such resemblance is accidental. These examples are used as an instructional scenario to illustrate appropriate handling of a difficult toxicology issue. In this scenario, a drug caused a toxicity in animals that was detected only by histopathologic analysis; if it were to develop in patients, no conventional clinical methods could be identified to monitor for it. It is not unusual for a firm to cancel clinical development plans for a lead drug candidate that causes such a toxicity, especially if such a drug is intended for use as a chronic therapeutic in a population of patients with a chronic disease. This case synthesis was inspired by a Food and Drug Administration (FDA) agreement to allow such a product to proceed into clinical trials after substantive pre-IND discussions and agreement on well-considered toxicology program designs. The scientists most closely involved in the strategy development included the sponsor's toxicologist, veterinary toxicologic pathologist, and pharmacokineticist, as well as the FDA's reviewing pharmacologist. The basis of this decision was thorough toxicity characterization (1-month studies in 2 species); correlating toxicities with a particular cumulative area under the curve (AUC) in both species; identification of the most sensitive species (the species that showed the lower AUC correlating with toxicity); allometric assessment of clearance of the drug in 3 nonhuman species; construction of a model of human kinetics (based on extrapolation from animal kinetics); and finally, estimation of clinical safety factors (ratios of the human estimated cumulative AUC at the proposed clinical doses, over the animal cumulative AUC that correlated with the no adverse effect levels). Industry and FDA scientists negotiated a joint assessment of risk and benefit in patients, resulting in the FDA permitting such a compound to enter into clinical trials for a serious autoimmune disease. Such constructive, early communication starts with the pre-IND meeting, and the conduct and planning for this meeting can be very important in establishing smooth scientific and regulatory groundwork for the future of a drug under IND investigation.

Keywords

Risk-benefit regulatory strategy safety margins histopathology pre-IND FDA interactions

References

Guidance for Industry (1994 ). S5A Detection of Toxicity to Reproduction for Medicinal Products. ICH. Available from OCTMA, HFM-40, CBER, FDA, 1401 Rockville Pike, Rockville, Maryland 20852-1448.

Guidance for Industry (1997 ). S6 Preclinical Safety Evaluation of Biotechnology-Derived Pharmaceuticals. ICH.

Guidance for Industry (1997 ). M3 Nonclinical Safety Studies for the Conduct of Human Clinical Trials for Pharmaceuticals. ICH. Available from OCTMA, HFM-40, CBER, FDA, 1401 Rockville Pike, Rockville, Maryland 20852-1448.

Guidance for Industry (1997 ). S3A A Standard Battery for Genotoxicity Testing of Pharmaceuticals. ICH. Available from: OCTMA, HFM-40, CBER, FDA, 1401 Rockville Pike, Rockville, Maryland 20852-1448.

Guidance for Industry (1998 ). Fast Track Drug Development Programs-Designation, Development, and Application Review. Available from: OCTMA, HFM-40, CBER, FDA, 1401 Rockville Pike, Rockville, Maryland 20852-1448.

Orphan Drug Regulation ( 1992 ). Final rule. 21 CFR part 316. Fed. Register 57(250). Available from OCTMA, HFM-40, CBER, FDA, 1401 Rockville Pike, Rockville, Maryland 20852-1448.