Regulatory Acceptance of Alternative Methods- Pharmaceuticals in the U.S. A. Jacobs 11/07 (not an official opinion)

Regulatory Acceptance of Alternative Methods-

Pharmaceuticals in the U.S.A. Jacobs

11/07(not an official opinion)

Overall • ICCVAM• OECD• In vitro assays• Flexibility in approaches• ICH• Combining of endpoints/considerate of

the 3 Rs• Implementation- the need for better

alternatives

ICCVAM

• FDA is an active participant in ICCVAM

– On the overall committee and most working groups on various alternatives and thus hopefully familiar with the issues

ICCVAM Agencies (a) • Regulatory Agencies • Consumer Product Safety Commission • Department of Agriculture • Department of the Interior • Department of Transportation • Environmental Protection Agency • Food and Drug Administration • Occupational Safety and Health Administration

ICCVAM Agencies (b) • Research Agencies • Agency for Toxic Substances and Disease Registry • Department of Defense • Department of Energy • National Cancer Institute • National Institute for Occupational Safety and Health • National Institute of Environmental Health Sciences • National Library of Medicine • National Institutes of Health, • Office of the Director

ICCVAM’s Mission (a)• To facilitate development, validation and

regulatory acceptance of new and revised regulatory test methods that

– reduce, refine, and replace the use of animals in testing

– while maintaining and promoting scientific quality and the protection of human health, animal health, and the environment

ICCVAM’s Duties (a )• To consider petitions from the public for

review and evaluation of validated test methods

• To review and evaluate new, revised, and alternative test methods

• To submit test method recommendations to U.S. Federal agencies and make agency responses (due within 180 days) available to the public

ICCVAM’s Duties (b)

• To facilitate and provide guidance on: – test method development – validation criteria and processes

• To facilitate: – acceptance of scientifically valid test

methods

• Interagency and international harmonization

ICCVAM Acceptance Criteria (a)

• Fits into the regulatory testing structure • Adequately predicts the toxic endpoint of

interest • Generates data useful for risk assessment • Adequate data available for specified uses • Robust and transferable • Time and cost-effective • Adequate animal welfare consideration (3Rs)

ICCVAM Acceptance Criteria (b)

• The proposed use of the test method will provide for equivalent or improved protection of human and/or animal health, or the environment

• Adopted from: Validation and Regulatory Acceptance of Toxicological Test Methods: A Report of the ad hoc Interagency Coordinating Committee on the Validation of Alternative Methods; NIH Pub. No. 97-3981, 1997

Regulatory Acceptance by U.S. Agencies

• ICCVAM does not dictate to U.S. regulatory agencies what tests or testing strategies to accept or use

• U.S. Agencies are bound by their regulatory mandates from the U.S. Congress

OECD (a)

• FDA and other agencies contribute to OECD expert pharm/tox working groups and guidelines

• For some agencies, OECD protocols/guidelines need to be followed

• OECD guidelines are geared toward evaluation of chemicals, not pharmaceuticals

OECD (b)• In the U.S. for pharmaceuticals, • Specific protocols are not generally required

and testing strategy is different from that for chemicals for which labeling for hazard is the goal

• Studies conducted according to OECD guidelines will be accepted, but may not be sufficient to answer a regulatory question

• For cosmetics, it is the sponsor’s responsibility to establish safety and to determine how (what methods)

Worker Exposure/Drug Discovery/Lead Selection vs Drug Evaluation

• Many in vitro and other alternative assays may be (are) used by drug companies for screening, to help in compound discovery and selection and to assess effects of exposure to the unfinished product

• For high deliberate exposure of humans, however, a screening assay will probably be insufficient to support studies in humans

In vitro Assays (a)

• May be used for the active ingredient (API) of a pharmaceutical formulation but may have limitations for entire formulations

• At some “high” concentrations, the incidence of false positives increases

• Often interested in reversibility

In vitro Assays (b)

• Limulus bacterial endotoxin test for pyrogenicity generally used in place of rabbits and currently ICCVAM is evaluating assays in human whole blood, PBMC and monocytoid cells

• Validation studies can suggest assays promising to be pursued by sponsors

• However, it would need to be demonstrated that the assay works for a particular product since that is a safety/regulatory need, and consequences of being wrong could be dire

In vitro Assays (c)

• 3T3 assay for photoirritation accepted, but a large percentage of false positives is seen – Some formulations are incompatible with

3T3 cells– Primarily for UVA absorbing since cells

can’t tolerate very much UVB• BCOP for severe ocular irritation accepted,

but for one drug, results in one lab indicated a severe ocular irritant (a score of 126) and in another lab a nonirritant (a score of 1.3)

In vitro Assays (d)

• Experience of false positive results discourages use of an assay– Companies follow-up on positives on their

own

• Some endpoints involve systemic interactions

• Need to relate effects to exposure when making a regulatory decision

Flexibility in What Specifically is Needed (a)

• Follow International Conference on Harmonization (ICH) agreements on what is needed and when in development

• Rather than a list of tests, consider what concerns need to be addressed during pharmaceutical development

Flexibility in What Specifically is Needed (b)

• Have potential human adverse effects at particular exposures been identified?

• What is a safe first dose in humans?

• How much toxicity is reasonable for humans at the particular stage of drug development?

• Is an identified adverse effect reversible?

Flexibility in What Specifically is Needed (c)

• How high is it reasonable to dose humans?

• What should be monitored in humans and how frequently?

• Is the drug reasonably safe for a person who wants to get pregnant or is pregnant

• What are the long-term effects of taking the drug?

Alternative Assays Accepted before Formal Validation (a)

• For pharmaceuticals, formal validation not required for an assay to be accepted for regulatory use – if adequate background data are provided to

demonstrate that the assay is capable of measuring the endpoints/effects claimed

– if the assay is a scientifically reasonable assay

Alternative Assays Accepted before Formal Validation (b)

• Sometimes alternatives are accepted to get data on usefulness for pharmaceuticals

• Examples: LLNA; 3T3; BCOP• LLNA was strongly recommended to drug

sponsors; false positives affected subsequent use and reliance on results; eagerly awaiting some in vitro alternatives

• 3T3 accepted but 7/8 positive results have turned out to be false positives

Alternative Assays Accepted before Formal Validation (c)

• BCOP accepted when direct exposure of finished product to eye not involved (e.g., dermal product on finger and eye then rubbed); experience with false positives may also affect use of this assay

Implementation (a)

• Alternatives mentioned in FDA guidances– LLNA– 3T3 Photocytotoxicity assay

• Exploratory IND Guidance– Less animal tox needed in fewer animals at

lower doses to help select drug candidates in limited studies in humans

• PreIND meeting with companies/ sponsors on product development plans

Implementation (b)

• Don’t ask for unnecessary studies

• Don’t ask for acute lethal tox studies

• Don’t ask for nonclinical photoallergy studies

• Combine endpoints when possible

Implementation (c)

• Draize tests not necessary for pharmaceuticals– Dermal irritation is part of another tox study– Ocular irritation usually part of another tox

study in which the active ingredient is diluted and is expected to be tolerated (the same material/formulation that will go into the human eye)

– Ocular irritation not evaluated if product causes dermal irritation

Implementation (d)

• Monthly Pharm/Tox supervisor meetings across all 16 human drug divisions in the FDA

• E-mail to share information

• Presentations at reviewer and supervisor retreats

• Workshops

Near-Term Goal

• Reduce animal use whenever possible without jeopardizing human health

Long-Term Goal

• Replace All Animal Testing

• Need alternatives that can address the questions that need to be answered in order to make regulatory decisions

The Dose-Limiting Step-the Assays

• For pharmaceuticals • The limitations and the limited utility of

the currently validated alternatives is the biggest impediment

• If we had reliable alternatives that could better address the regulatory questions, they would be strongly encouraged and easily accepted