Guidance for Industry 

Considerations for Developmental 

Toxicity Studies for Preventive and 

Therapeutic Vaccines for Infectious 

Disease Indications 

Additional copies of this guidance are available from the Office of Communication, 

Training and Manufacturers Assistance (HFM-40), 1401 Rockville Pike, suite 200N, 

Rockville, MD 20852-1448 or by calling 1-800-835-4709 or 301-827-1800, or from the 

Internet at http://www.fda.gov/cber/guidelines.htm. 

For questions on the content of this guidance, contact CBER Division of Vaccines and 

Related Products Applications at (301) 827-3070. 

U.S. Department of Health and Human Services 

Food and Drug Administration 

Center for Biologics Evaluation and Research 

February 2006 
Contains Nonbinding Recommendations

TABLE OF CONTENTS 

I. INTRODUCTION............................................................................................................. 1

II. BACKGROUND ............................................................................................................... 2

III. VACCINE TARGET POPULATION AND TIMING OF PRE-CLINICAL 

DEVELOPMENTAL TOXICITY STUDIES ................................................................ 3

IV. DESIGN OF DEVELOPMENTAL TOXICITY STUDIES.......................................... 4

A. General Considerations and Recommendations ................................................ 4

B. Specific Considerations ........................................................................................ 6

V. REFERENCES................................................................................................................ 12

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Contains Nonbinding Recommendations 

Guidance for Industry1 

Considerations for Developmental Toxicity Studies for Preventive 

and Therapeutic Vaccines for Infectious Disease Indications 

topic. 

FDA or the public. You can use an alternative approach if the approach satisfies the 

If you want to discuss an alternative 

approach, contact the appropriate FDA staff. If you cannot identify the appropriate FDA staff, 

call the appropriate number listed on the title page of this guidance. 

This guidance represents the Food and Drug Administration’s (FDA’s) current thinking on this 

It does not create or confer any rights for or on any person and does not operate to bind 

requirements of the applicable statutes and regulations. 

I. INTRODUCTION 

This guidance is intended to provide you, sponsors, with recommendations for the conduct of 

developmental toxicity2

 studies for investigational preventive and therapeutic vaccines for 

infectious disease indications. The recommendations set forth in this document pertain to the 

assessment of the developmental toxicity potential of preventive and therapeutic vaccines for 

infectious diseases indicated for females of childbearing potential and pregnant individuals.3 

This guidance applies prospectively to investigational vaccines, i.e., vaccines under 

investigational new drug applications (IND) and vaccines the subject of a new biologics license 

application (BLA). These recommendations do not apply retrospectively to already licensed 

vaccines except those the subject of additional INDs. This guidance document finalizes the draft 

guidance entitled “Guidance for Industry: Considerations for Reproductive Toxicity Studies for 

Preventive Vaccines for Infectious Disease Indications” dated August 2000 (65 FR 54534; 

September 8, 2000). 

FDA’s guidance documents, including this guidance, do not establish legally enforceable 

responsibilities. Instead, guidances describe the FDA’s current thinking on a topic and should be 

viewed only as recommendations, unless specific regulatory or statutory requirements are cited. 

The use of the word should in FDA’s guidances means that something is suggested or 

1

 The Maternal Immunization Working Group in the Center for Biologics Evaluation and Research at the Food and 

Drug Administration prepared this guidance. The document was revised based on public comments submitted to 

the Division of Dockets Management on the draft guidance dated August 2000, and on recommendations made by 

an expert panel convened at a Workshop entitled “Non-clinical Safety Evaluation of Preventive Vaccines: Recent 

Advances and Regulatory Considerations” held December 2 & 3, 2002, Arlington, VA, discussing approaches for 

developmental toxicity assessments for vaccines. 2

 Developmental toxicity is any adverse effect induced prior to attainment of adult life. This includes effects 

induced or manifested in the embryonic or fetal period and those induced or manifested postnatally (Ref. 1). 

3

 This document does not address concerns regarding male reproductive toxicity and male and female fertility 

studies. 

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recommended, but not required. 

II. BACKGROUND 

The Center for Biologics Evaluation and Research (CBER) reviews a broad spectrum of 

applications for investigational vaccines intended for the prevention and treatment of infectious 

diseases and indicated for immunization of adolescents and adults. Thus, the target population 

for vaccines often includes females of childbearing potential who may become pregnant during 

the vaccination period. A number of vaccines are in clinical development specifically for 

maternal immunization indications with the goal of preventing infectious disease in the pregnant 

mother and/or neonate through passive antibody transfer from mother to fetus. Unless the 

vaccine is specifically indicated for maternal immunization, no studies are conducted prior to 

product licensure to determine the vaccine’s safety in pregnant women. During clinical 

development of most vaccines not specifically intended for use during pregnancy, pregnant 

women are ineligible to participate in clinical trials. If pregnancy occurs during a study, 

treatment is usually discontinued and the woman does not receive additional immunizations. 

Consequently, there are few clinical data to address developmental toxicity of the vaccine in 

pregnant women or females of childbearing potential at the time of product licensure. 

As more women of childbearing potential participate in clinical trials and as more preventive and 

therapeutic vaccines are developed for adolescents and adults, there is increasing concern about 

the unintentional exposure of an embryo/fetus before information is available about the risk 

versus benefit of the vaccine. Also, following approval, vaccines not indicated for use during 

pregnancy may be recommended by health policy makers for use in pregnant women (Ref. 2). In 

addition, use of licensed vaccines in females of childbearing potential will likely result in 

inadvertent exposure of the pregnant woman and her fetus to the vaccine. Considering that more 

than half of pregnancies in the U.S. are unintended, it is unlikely that vaccine exposure would be 

avoided in these pregnancies prior to their clinical recognition (Ref. 3). In these situations, in the 

absence of clinical data, it is difficult for the practitioner to make an informed risk assessment, 

even in situations where immunization of pregnant women may be appropriate. 

Until recently, few licensed vaccines have been tested for developmental toxicity in animals 

prior to their use in humans. However, for the reasons listed above, we, FDA, recommend that 

you address during the IND studies the risks versus the benefits of immunization programs for 

pregnant women and/or females of childbearing potential by performing developmental toxicity 

studies in animal models. Potential risks involved in prenatal immunization programs include 

developmental adverse effects caused by the inherent biological activity of the vaccine antigen 

and constituents of the vaccine product (e.g., adjuvants, preservatives, and stabilizers). In 

addition, potential adverse effects on the pregnancy status and or the developing embryo/fetus 

may be the result of maternal immune modulation (Refs. 4 and 5). 

Because pregnant women are usually excluded from clinical trials, data from developmental 

toxicity studies in animal models offer one approach to screen for potential developmental 

hazards. Studies in animal models may frequently present the only information available to draw 

conclusions regarding developmental risk to be included in the product labeling required under 

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Contains Nonbinding Recommendations 

section 201.57(f)(6) in Title 21 Code of Federal Regulations (§ 201.57(f)(6)). As there is 

virtually no scientific literature on animal developmental toxicity testing for vaccine products, 

this guidance will outline general and specific recommendations that should be taken into 

account in the assessment of developmental toxicity for preventive and therapeutic vaccines for 

infectious disease indications. 

III. VACCINE TARGET POPULATION AND TIMING OF PRE-CLINICAL 

DEVELOPMENTAL TOXICITY STUDIES 

For the purpose of this document, vaccines are a heterogeneous class of preventive, in some 

cases therapeutic, medicinal products, the administration of which is intended to elicit an 

immune response(s) that can prevent and/or lessen the severity of one or more infectious 

diseases. A vaccine may be a live attenuated preparation of bacteria, viruses, or parasites, 

inactivated (killed) whole organisms, living irradiated cells, crude fractions or purified 

immunogens, including those derived from recombinant deoxyribonucleic acid (DNA) in a host 

cell, conjugates formed by covalent linkage of components, synthetic antigens, polynucleotides 

(such as plasmid DNA vaccines), living vectored cells expressing specific heterologous 

immunogens, or cells pulsed with immunogen. It may also be a combination of vaccines listed 

above. Antigens may be presented plain or delivered in combination with other antigens, 

adjuvants, additives and other excipients. Therapeutic vaccines for non-infectious diseases and 

monoclonal antibodies used as immunogens are not considered in this guidance (Ref. 6). 

Developmental toxicity studies are usually not necessary for vaccines indicated for 

immunization during childhood. However, for vaccines indicated for adolescents and adults and 

for vaccines that are indicated or may have the potential to be indicated for immunization of 

pregnant women, we recommend that you consider developmental toxicity studies. 

There are currently differences in the timing of these developmental toxicity studies, as follows, 

to support inclusion of either pregnant individuals or females of childbearing potential in clinical 

trials. 

Maternal immunization: For products indicated specifically for immunization of pregnant 

women, we recommend that you have the data from non-clinical developmental toxicity studies 

available prior to the initiation of any clinical trial enrolling pregnant women. 

Females of childbearing potential: For vaccines indicated for females of childbearing potential, 

you may include subjects in clinical trials without non-clinical developmental toxicity studies, 

provided that appropriate precautions are taken by subjects enrolled in these trials to avoid 

vaccination during pregnancy, such as pregnancy testing and use of birth control. For these 

products, we recommend that you include data from developmental toxicity studies with the 

initial BLA submission (§ 601.2), regardless of whether such studies have been submitted earlier 

to the IND. 

Males: Currently, males may be included in Phase I, II, and III clinical trials in the absence of 

nonclinical male fertility studies, although such studies may be recommended for certain 

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products in the future. 

IV. DESIGN OF DEVELOPMENTAL TOXICITY STUDIES 

A. General Considerations and Recommendations 

The decision whether a developmental toxicity study needs to be performed should be 

made on a case-by-case basis taking into consideration historical use, product features, 

intended target population and intended clinical use. We recommend the developmental 

toxicity study be designed to detect potential developmental adverse effects induced by 

components present in the vaccine formulation. However, despite efforts to maximize 

the predictive value of developmental toxicity studies, there may always be limitations in 

evaluating or screening for potential risks and thus, limitations in reducing the 

uncertainties of risk. Also, lack of adverse effects on embryo/fetal development in an 

animal study does not necessarily imply absence of risk for humans. Factors that may 

limit risk prediction include, but are not limited to, species-specific differences in the 

immune response, different developmental time lines, and differences in placentation. 

Nevertheless, developmental toxicity studies in animal models are the best currently 

available non-clinical tools to screen for adverse developmental effects of the product in 

humans. Information about developmental risk from animal data is frequently the only 

information available at the time of product licensure. The good laboratory practice 

regulations in 21 CFR Part 58 apply to nonclinical laboratory studies that support or are 

intended to support applications. 

1. Previous clinical experience 

All available clinical experience in pregnant women should be considered in any 

potential application with respect to the design of developmental toxicity studies 

in animals. Clinical experience derived from immunization of pregnant women 

may be helpful in the evaluation of the potential for any adverse outcome on the 

viability and development of offspring. Such information may also aid in the 

design/monitoring of appropriate non-clinical studies, and for product labeling. 

However, clinical data that may have been obtained from small numbers of 

pregnant women enrolled in non-IND studies, e.g., immunized with the vaccine or 

a related product, will generally not replace the need for animal developmental 

toxicity studies. 

2. Previous non-clinical experience 

We recommend that you review all data generated from prior acute or repeat dose 

non-clinical toxicity studies for their possible contribution to the interpretation of 

any adverse developmental effects that appear in the developmental toxicology 

studies. In addition, data from prior non-clinical studies do frequently form the 

basis for the choice of the animal model and vaccine dose used in the 

developmental toxicity study. 

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3. Vaccine formulation 

We recommend that you perform the non-clinical developmental toxicity study on 

the same lot as proposed for the clinical trial. If this is not feasible, we 

recommend that non-clinical lots be comparable to clinical lots with respect to 

physico-chemical data, stability, and formulation and be manufactured in 

accordance with applicable cGMPstandards. 

In addition, even though pivotal clinical studies are frequently conducted with an 

intended final formulation, optimizations of formulations are frequently made 

prior to product marketing. In these cases, we will assess, on a case-by-case 

basis, the applicability of non-clinical studies conducted with earlier clinical 

formulations of the vaccine to the commercial formulation of the vaccine. For a 

product specifically intended for maternal immunization, we recommend that you 

perform non-clinical developmental toxicity studies in advance of clinical studies 

that enroll pregnant women. In these cases, to avoid performing multiple 

developmental toxicology studies during development, you may find it 

advantageous to conduct Phase I and Phase II studies in non-pregnant subjects. 

Results from these studies can be used as the basis for advancing the most 

promising product formulation(s) to studies that enroll pregnant women. 

4. Vaccine product class 

There are a number of vaccines in clinical development that may be similar to or 

of the same product class as either investigational or already licensed products, 

for which developmental toxicity studies may have been performed. In these 

cases, we will examine the need for additional development toxicity studies for 

the product under investigation on a case-by case basis. Regarding combination 

vaccines in clinical development, for which the individual components are 

licensed and on which developmental toxicity assessments have been performed, 

we may not recommend further developmental toxicity assessments. However, if 

the combination vaccine is formulated with new adjuvant, new preservative or if 

significant changes to the individual products or their manufacture were made 

and/or concerns exist that combining the individual licensed products may 

increase their toxic potential, we recommend additional developmental toxicity 

studies. Similarly, if no developmental toxicity studies have been conducted for 

the individual licensed or unlicensed components, we recommend that you 

conduct developmental toxicity studies. In some instances, documentation on 

clinical and epidemiological data, e.g., exposure to the infectious agent or use of 

related, licensed vaccines during pregnancy, may be sufficient to evaluate the risk 

of the investigational product and may be provided by you and considered by 

FDA in determining the need for developmental toxicity studies in animal 

models. In these cases, we recommend that you contact FDA to reach agreement 

regarding the need for additional developmental toxicity studies for that particular 

product. 

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5. Application of ICH guidance document S5A 

The ICH S5A guidance document entitled "Detection of Toxicity to Reproduction 

for Medicinal Products," addresses the design of animal studies primarily for 

detection of toxicity on reproduction, dividing the reproductive cycle into 

different segments, defined as stages A – F (see Ref. 1). The ICH S5A guidance 

suggests that different studies can be conducted to address the various segments 

of the reproduction cycle. For preventive and therapeutic vaccines for infectious 

diseases, the primary concern is potential untoward effects of the test article on 

development and growth of the embryo and fetus. Thus, the primary focus is on 

developmental toxicity studies to detect adverse effects on the pregnant/lactating 

female and development of the embryo/fetus and the offspring following exposure 

of the female to the vaccine from implantation through the end of pregnancy, with 

follow-up of the offspring through weaning. These stages are defined as stages C, 

D, and E in the ICH S5A document. Depending on the product and on a case-bycase basis, we might require additional studies to address additional segments of 

the reproductive cycle. 

We recommend use of the ICH S5A guidance as a general point of reference to 

assist you in the general design of developmental toxicity studies and evaluation 

of endpoints. However, we want to emphasize distinguishable factors relevant to 

vaccines. The most important feature distinguishing vaccines from other 

pharmaceutical products is the intended vaccine-induced immune response. Also, 

vaccines are usually administered in limited, episodic dosages with months or 

even years between doses. Vaccines include a broad range of product categories 

such as live attenuated, inactivated, recombinant, polynucleotide, polysaccharide, 

protein antigens, vectored vaccines, and conjugate vaccines. These may be 

adjuvanted or consist of a combination of different vaccine antigens. Thus, given 

the complexity of these issues, the non-clinical testing strategies outlined in the 

ICH S5A document may not be directly applicable to vaccines, and study designs 

outlined in the ICH S5A document may need to be tailored to the vaccine product 

under consideration. Outlined below are specific considerations that we 

recommend you take into account when designing developmental toxicity studies 

for vaccines. We also recommend that prior to the conduct of the study, you 

establish an early dialogue with CBER to reach agreement on a specific protocol 

including study endpoints. 

B. Specific Considerations 

1. Animal model 

We recommend that you provide in your IND submission a justification for the 

choice of the animal model to be used in the developmental toxicity study. This 

should include a demonstration that the species is able to develop an immune 

response to the vaccine antigen, even though there may be quantitative and 

qualitative differences in immune responses between species. The laboratory 

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species most often used for developmental toxicity studies, on the basis of 

availability of background data and historical experience, are rats, rabbits and 

mice. Most human vaccines are immunogenic in rodents or rabbits. In some 

cases, only non-human primates may show an adequate immune response. 

However, because of the technical and logistic difficulties involved in using nonhuman primates for developmental toxicity studies, we recommend you only 

consider these animals if no alternative models are available. 

In addition to demonstrating an immune response in the pregnant female, we 

recommend that you verify the exposure of the fetus to maternal antibodies. 

Thus, since there are differences between primates, non-rodents, and rodent 

animal species in terms of timing of maternal antibody transfer to the offspring, 

we recommend that you evaluate the pre- and postnatal exposure of the offspring 

to maternal antibody as a criterion for selecting the most appropriate experimental 

model. In addition, the species selected should be amenable to fetal and postnatal 

examinations. 

In cases where lack of an appropriate animal model hinders the assessment of an 

immune response, developmental toxicity studies may still provide important 

information regarding potential embryo/fetal toxic effects of the vaccine 

components/formulation and safety of the product in the pregnant animal. 

In most cases, it is sufficient to conduct developmental toxicity studies using only 

one species; thus, there is no requirement for the routine use of two species, i.e., 

one rodent and one non-rodent. 

The number of animals per group should be sufficient to allow meaningful 

interpretation of the data. For example, for a developmental toxicity study using 

rats or rabbits, we recommend that you assign an adequate number of animals to 

each group to allow an evaluation of at least 40 animals per group. These animals 

can be further allocated to the Caesarean and littering subgroup using 20 animals 

each. 

2. Pharmacodynamics 

We recommend that you obtain information about the onset and duration of the 

antibody response in pilot studies because these data may help in selecting the 

proper species, study design, and dosing schedules. Initial information can be 

derived from non-pregnant animals. However, it may also be necessary to 

perform these pilot studies in a small group of pregnant animals to evaluate 

antibody formation in relation to test article exposure and placental antibody 

transfer to the fetus if there is evidence that antibody formation may differ in 

pregnant versus non-pregnant animals. 

We recognize that antibody induction presents only one aspect of the overall 

immune response induced by the vaccine and that other immunological 

parameters, such as cytokines and induction of cytotoxic T cells, may be as 

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important. However, given the relative lack of validated assays to assess the 

induction of these other parameters, antibody assessments are currently used as a 

marker for vaccine induced effects in these studies. This does not exclude the 

evaluation of additional immunologic parameters on a case-by-case basis. For 

example, if data are available which indicate that a vaccine antigen induces a 

particular cytokine response, respective cytokine measurements may be included, 

especially if the cytokine is one that may affect pregnancy. 

3. Experimental procedure 

In order to detect adverse effects on the pregnant/lactating female animal and 

development and growth of the embryo/fetus and the offspring, we recommend 

that the female be exposed to the vaccine during the interval from implantation 

through closure of the hard palate and also at later stages of pregnancy. The 

offspring should be followed to weaning and observed for normal growth and 

development. We recommend that you submit one subgroup of pregnant females 

to Caesarean examination at the end of pregnancy for routine uterine and fetal 

examinations, and allow another subgroup to litter and rear their offspring to 

weaning in order to monitor the post-natal development of the offspring up to 

weaning. 

4. Dosage 

We recommend that you assess a single dose level that is capable of inducing an 

immune response in the animal model. Where possible, we recommend that you 

administer animals the maximum human dose (e.g., 1 human dose = 1 rabbit 

dose) regardless of body weight. If it is not feasible to administer the maximum 

human dose (e.g., limitation in total volume that can be administered; dosing 

induced local toxicity affecting pregnancy), we recommend that you administer a 

dose that exceeds the human dose on a mg/kg bases while still capable of 

inducing an immune response in the animal. 

5. Frequency and route of administration 

We recommend that the vaccination regimen optimize maternal antibody titers 

throughout the embryonic, fetal, and early post-natal periods. Timing and number 

of doses will depend on the onset and duration of the immune response of the 

particular product. Because of concerns that a daily dosing regimen may lead to 

overexposure to the vaccine antigen that could potentially result in immune 

tolerance, we recommend episodic dosing of pregnant animals rather than daily 

dosing. In addition, episodic dosing appears to be more relevant, as it better 

mimics the clinically proposed immunization schedule for most preventive and 

therapeutic vaccines for infectious disease indications. Considering the short 

gestational period of animal species most frequently used, it may be necessary to 

administer priming doses to the animals several days or weeks prior to mating in 

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order to elicit a peak antibody production during the critical phases of pregnancy, 

i.e., the period of organogenesis. 

When dosing prior to implantation, stress reactions may be observed in the animal 

that may affect the pregnancy status. Therefore, with treatment of animals prior 

to mating/insemination, it may be necessary to add more animals to the study to 

ensure that sufficient animals become pregnant for evaluation. 

We recommend that you administer one or several additional doses during 

organogenesis (i.e., implantation to closure of the hard palate) to evaluate 

potential direct embryotoxic effects of the components of the vaccine formulation 

and to maintain a high level of antibody throughout the remainder of gestation. In 

certain cases, subgroups of animals that are dosed at certain time points may be 

included to evaluate if the vaccine acts as a selective toxicant, bearing in mind 

that it may be difficult to adjust vaccine administration with gestational timelines. 

We recommend that the route of administration mimic the clinical intended route 

of administration. 

6. Control groups 

We recommend that you dose control animals with placebo at the same time and 

frequency as test group animals. Since the potential toxicity of each of the 

components presented in the vaccine formulation will need to be evaluated, we 

recommend that you consider additional groups if components other than the 

vaccine antigen contained in the vaccine formulation (e.g. excipients, 

preservatives) cause effects or affect the activity of the test substance. In 

addition, if the vaccine is formulated with adjuvant, we recommend that you 

consider the inclusion of an adjuvant-only control arm, particularly if the adjuvant 

is novel. 

7. Endpoints 

In general, the study endpoints should include those recommended for studies for 

effects on prenatal and postnatal development including maternal functions as 

stated in the ICH S5A document (see Ref. 1). When deciding on the endpoints to 

be evaluated, we recommend that you take into consideration the nature of the 

vaccine and particular concerns associated with that product. The following 

parameters listed are intended to provide a basic panel of endpoints to be 

evaluated that are not meant to be all-inclusive. 

a. Premating/preinsemination period 

Clinical observations including data on general appearance and body weights 

should be obtained weekly and on days of test article administration. 

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b. Gestational period 

We recommend that you observe maternal animals during the study for signs of 

morbidity and mortality, and record clinical observations regarding general 

appearance and behavior. We recommend that the evaluations include body 

weight and body weight change, potential signs of local toxicity, food 

consumption, duration of pregnancy, abortions, premature deliveries, and 

parturition (for maternal animals not subjected to Caesarian sectioning). 

c. Caesarean sectioning group 

i. Maternal Observations 

At terminal examination of groups subjected to Caesarean sectioning, we 

recommend that you conduct a necropsy (macroscopic examination) and 

preserve maternal tissue with macroscopic findings for histological 

evaluations as deemed necessary by the gross findings. For example, 

histological evaluations may be indicated if you observe effects on organ 

to body weight ratios. We recommend that you record the number and 

distribution of corpora lutea, implantation sites, viable and nonviable 

fetuses, and early and late resorptions and that you perform a gross 

evaluation of the placenta. 

ii. Fetal examinations 

We recommend that you obtain individual body weights of live fetuses 

and examine each viable fetus for gross external, visceral, and skeletal 

alterations. Late resorptions and dead fetuses should also be examined for 

gross external alterations to the extent possible. All fetuses should be 

examined internally to determine sex. 

d. Natural delivery group 

i. Maternal observations 

In addition to the parameters outlined in section IV.B.7.b (Gestational 

period), we recommend that you determine the duration of gestation and 

parameters such as the fertility index, gestation index, and live birth index. 

Animals that deliver a litter should be sacrificed at the end of the preweaning period. We recommend that you perform a gross necropsy of the 

thoracic, abdominal and pelvic viscera, and record the number and 

distribution of implantation sites as well as any observed abnormalities. 

Animals that die or are sacrificed because of moribund condition, abortion 

or premature delivery should be examined for the cause of death and 

pregnancy status recorded. We recommend that you also examine aborted 

fetuses and/or delivered pups to the extent possible. 

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ii. F1 generation 

We recommend postnatal follow-up from birth to weaning to assess 

normal growth, body weight gain, and nursing activity as indicators for 

normal development. We also recommend that you include into the study 

design tests to screen for normal neuro-development, for example, 

auditory and visual function tests. Viability and lactation indices should 

be determined and individual sexes should be recorded. At terminal 

sacrifice, we recommend that you perform a necropsy, record any 

abnormalities and retain gross lesions for possible histological 

examinations. We recommend that you evaluate pups that die before 

examination for vital status at birth and examine pups found dead for 

gross lesions and cause of death. 

8. Immunological endpoints 

In addition to evaluating potential developmental adverse effects and adverse 

effects on the pregnant animal, we recommend that you include an assessment of 

the vaccine induced antibody response to verify exposure of the embryo/fetus to 

maternal antibody. Serum specimen from maternal animals prior to and at 

additional time points following dosing should be collected to assess the 

development of antibodies. Sampling is usually conducted prior to test article 

administration and at day of Caesarean sectioning (where applicable) and at the 

end of the weaning period. 

In addition, we recommend that you obtain cord blood samples to assess placental 

transfer of maternal antibodies from animals in the Caesarean subgroup. We 

recommend that you also assess antibody levels from a representative number of 

pups/litters at the end of the weaning period to verify exposure of the neonates to 

maternal antibody induced. Antibody evaluations in developmental toxicity 

studies serve the purpose of verifying an effect of the vaccine in the test species 

as opposed to evaluating potential immunotoxic effects. You may evaluate 

additional immune parameters on a case-by-case basis. For example, if evidence 

exists that the vaccine antigen or other vaccine components can trigger the release 

of a particular cytokine potentially affecting pregnancy, you may include 

respective assessments. 

9. Additional assessments 

In cases where non-clinical developmental toxicity studies reveal vaccine-induced 

adverse effects on either the pregnant/lactating animal, embryo/fetal development, 

or development of the offspring, we recommend you conduct further animal 

studies to evaluate the cause of the effect. Such studies may include broader 

immunological evaluations, e.g., histochemical analysis for antibody depositions, 

as well as neurological assessments. 

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V. REFERENCES 

1. International Conference on Harmonization (ICH) Harmonized Tripartite Guideline for 

Industry (ICH-S5A) Detection of Toxicity to Reproduction for Medicinal Products, (59 

FR 48746, September 22, 1994), http://www.fda.gov/cder/guidance/s5a.pdf. 

2. Recommended adult immunization schedule-United States, 2002-2003, MMWR October 

11, 2002, Vol. 51 (40); 904-908. 

3. Colley, Gilbert B., Brantley, M.D., Larson, M.K., Family Planning Practices and 

Pregnancy Intention, 1997. Atlanta, GA: Division of Reproductive Health, National 

Center for Chronic Disease Prevention and Health Promotion, Centers for Disease 

Control and Prevention, 2000, 

http://www.cdc.gov/reproductivehealth/prams/pdf/97/PRAMS_sr_97.pdf. 

4. Barrow, P.C., Reproductive toxicology studies and immunotherapeutics. Toxicology 185 

(2003), 205-212. 

5. Thellin, O., Heinen, E., Pregnancy and the immune system: between tolerance and 

rejection. Toxicology 185 (2003), 179-184. 

6. Guidance for Industry: Content and Format of Chemistry, Manufacturing and Controls 

Information and Establishment Description Information for a Vaccine or Related Product 

(January 1999), http://www.fda.gov/cber/gdlns/cmcvacc.pdf. 

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