Guidance for Industry 


M4: The CTD  Efficacy   
 

Questions and Answers 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. Department of Health and Human Services 
 
Food and Drug Administration 
 
Center for Drug Evaluation and Research (CDER) 
 
Center for Biologics Evaluation and Research (CBER)
  
 
December 2004 
 
ICH 
 
 
Revision 3 

   

 
Guidance for Industry 
 


M4: The CTD  Efficacy   
 

Questions and Answers 
 
 
 
Additional copies are available from:
  
 
Office of Training and Communication 
 
Division of Drug Information, HFD-240 
 
Center for Drug Evaluation and Research 
 
Food and Drug Administration 
 
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Rockville, MD 20857 
 
(Tel) 301-827-4573
 
 http://www.fda.gov/cder/guidance/index.htm  

 
Office of Communication, Training and  

Manufacturers Assistance, HFM-40  

Center for Biologics Evaluation and Research
 
 Food and Drug Administration 
 
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http://www.fda.gov/cber/guidelines.htm. 
 
 (Tel) Voice Information System at 800-835-4709 or 301-827-1800 
 
 
 
 
 
 
U.S. Department of Health and Human Services 
 
Food and Drug Administration 
 
Center for Drug Evaluation and Research (CDER) 
 
Center for Biologics Evaluation and Research (CBER) 
 
 
December 2004  

ICH 
 
 
Revision 3 

   
TABLE OF CONTENTS  
 
 
 
I.   INTRODUCTION .................................................................................................................1 
 
II.   BACKGROUND....................................................................................................................2 
 
III.   QUESTIONS AND ANSWERS............................................................................................2 
 
  Contains Nonbinding Recommendations  
1
 
Guidance for Industry  
M4: CTD  Efficacy  

Questions and Answers  

 
 
 
 
 
This guidance represents the Food and Drug Administration's (FDA's) current thinking on this topic.  It 
does not create or confer any rights for or on any person and does not operate to bind FDA or the public.   
You can use an alternative approach if that approach satisfies the requirements of the applicable statutes 
and regulations.  If you want to discuss an alternative approach, contact the FDA staff responsible for 
implementing this guidance.  If you cannot identify the appropriate FDA staff, call the appropriate 
number listed on the title page of this guidance.   
 
 
 
 
I.   INTRODUCTION  
 
This is one in a series of guidances that provide recommendations for applicants preparing the 
Common Technical Document for the Registration of Pharmaceuticals for Human Use (CTD) for 
submission to the U.S. Food and Drug Administration (FDA).  This guidance provides answers 
to questions that have arisen since the finalization of the harmonized CTD guidance documents 
in November 2000.  This guidance specifically addresses questions related to efficacy.  Other 
question and answer (Q &A) guidances are under development to address general questions as 
well as questions related to quality and safety.  The questions and answers provided here reflect 
the consensus of the ICH parties.  
  
This guidance is being revised to include additional questions.  
 
FDA's guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the Agency'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 Agency guidances means that something is suggested or 
recommended, but not required.  
                                                 
1  This guidance was developed within the M4 CTD-Efficacy Implementation Working Group of the International 
Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) 
and has been subject to consultation by the regulatory parties, in accordance with the ICH process. This document 
has been endorsed by the ICH Steering Committee at Step 4 of the ICH process, June 10, 2004. At Step 4 of the 
process, the final draft is recommended for adoption to the regulatory bodies of the European Union, Japan, and the 
United States.  
 
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  Contains Nonbinding Recommendations  
 
II. 	  BACKGROUND  
 
The guidance for industry issued in November 2000 on preparing the CTD was divided into four 
separate documents (1) M4:  Organization of the CTD, (2) M4: The CTD  Quality, (3) M4: 
The CTD  Efficacy, and (4) M4: The CTD  Safety.  Since implementation of these 
guidances, a number of questions regarding the various CTD documents have been submitted to 
the various ICH regions.  The ICH has developed a process for responding to questions 
submitted to the ICH Web site.  
 
 
III. 	  QUESTIONS AND ANSWERS  
 
Q1:  	 Clinical study reports contained in Module 5 are cited in the Clinical Overview and/or 
the Clinical Summary in Module 2. Each clinical study report may be given a unique 
short name when cited. Does the method of citing and naming have to be uniform 
throughout all modules?  
 
A1: 	  We recommend that each study have a unique short identifier that is used consistently 
throughout the application.  The applicant can select the identifier.  The full title of the 
study is provided in the Tabular Listing of All Clinical Studies (Section 5.2)  
 
 
Q2:  	 Definitions/Terminology  
   
What is the definition of Common Adverse Events as used in the CTD?  
 
A2: 	  Guidance is provided by ICH E3 Guideline.  
 
 
Q3:  	 Section Numbering/Title (in Module 5)  
   
In Module 5 of the CTD, is it necessary to have a section number for each clinical 
study report in a certain section, or is it enough just to mention the title:  
    5.3.5 Report of Efficacy....  
    5.3.5.1 Study Reports....  
    5.3.5.1.1 Placebo Controlled.... 

       Study XXX 
 
 
A3: 	  See ICH granularity document.  
 
 
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  Contains Nonbinding Recommendations  
Q4:  	 How many pages should a Clinical Summary be for an application that contains 
multiple indications?  
 
A4: 	  The estimated size of this document is 50-400 pages, assuming one indication.  
Applications that include multiple indications will be larger, reflecting the submission of 
multiple efficacy sections.  
 
 
Q5:  	 Section 2.7.3.3 Comparisons and Analyses of Results Across Studies  
   
The Guideline provides This section should also cross-reference important evidence 
from Section 2, such as data that supports the dosage and administration section of the 
labeling. However, this Guideline also provides a Section, 2.7.3.4. Analysis of 
Clinical Information Relevant to Recommended Dose. Please specify how to 
differentiate the two sections 2.7.3.3 and 2.7.3.4.  
 
A5: 	  Section 2.7.3.3 summarizes the data across all studies that characterize efficacy of the 
drug; Section 2.7.3.4 provides an integrated summary of the dose-response or blood 
concentration-response relationships of effectiveness.  In both cases, supportive data from 
Section 2.7.2 can also be incorporated.  
 
 
Q6:  	 Overall Extent of Exposure  
   
In the Guideline, a table is required to be generated to present the overall extent of 
drug exposure in all phases of the clinical development. Should the table include 
patients alone or patients and healthy subjects?  
 
A6: 	  That table should refer to all subjects exposed to at least one dose of the drug product.  
Appropriate subsets of subjects relevant to the proposed indications should also be 
identified and considered.  
 
 
Q7:  	 Summary of Clinical Safety  
   
Where should information be described concerning the validity of extrapolation of 
foreign clinical safety data to a new region?  
 
A7: 	  Summaries of any bridging studies using clinical endpoints (i.e., certain studies intended 
to evaluate the ability to extrapolate certain types of foreign clinical data to the new 
region (see ICH E5)) should be included in Section 2.7.3.2.  Where appropriate, such 
information should also be described in the summarization of safety data as related to 
intrinsic and extrinsic ethnic factors (ICH E5), in Sections 2.7.4.5.1 and 2.7.4.5.2. 
Finally, some applications might include in Section 5.3.5.3 a detailed analysis of 
bridging, considering formal bridging studies, other relevant clinical studies, and other 
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  Contains Nonbinding Recommendations  
appropriate information.  Such information should be included in that detailed analysis of 
bridging.  
 
 
Q8:  	 Bioavailability/Bioequivalence Study Data  
   
Where should the information on bioequivalence studies for a generic application be 
included?  
 
A8:	   Bioavailability study reports should be included in Module 5 (Clinical documentation), 
under section 5.3.1 Reports of Biopharmaceutical Studies.  More specifically, reports 
of comparative Bioavailability/Bioequivalence studies should go under section 5.3.1.2.  
 
 
Q9:  	 Tabular Listing of Clinical Studies in Paper CTD  
   
In Module 5, 5.2 is denoted as the Tabular Listing of all Clinical Studies.  Is this 
section for a summary listing of all clinical studies in the submission, or it is for the 
listing of the individual study reports? In other words, should the listings from the 
appendices of the individual study reports be included here, rather than as an appendix 
to the CSR, or are these only listings that summarize all studies?  
 
A9: 	  The tabular listing described in section 5.2 is a listing of all clinical studies in the 
submission.  
 
An example of such a listing is given in Table 5.1.  
 
 
Q10  	 Integrated Summary of Safety and Effectiveness  
 
Does the CTD section on safety in Module 2 replace the section under 21 CFR 
314.50(d)(5)(v)-(vi) calling for integrated summary of safety and effectiveness 
(ISS/ISE)?  
 
A10:  	 The ISS/ISE are critical components of the safety and effectiveness submission and are 
expected to be submitted in the application in accordance with the regulation.  FDAs 
guidance Format and Content of Clinical and Statistical Sections of Application gives 
advice on how to construct these summaries.  Note that, despite the name, these are 
integrated analyses of all relevant data, not summaries.  
 
The Clinical Safety sections of the CTD follow approximately the outline of the sections 
of the ISS/ISE, although they are somewhat modified by experience with ICH E-3 
(Structure and Content of Clinical Study Reports). The CTD Clinical Overview and 
Summary in Module 2 will not usually contain the level of detail expected for an ISS.  It 
may contain the level of detail needed for an ISE, but this would need to be determined 
on a case-by-case basis.  
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  Contains Nonbinding Recommendations  
 
If the requirements of 21 CFR 314.50 can be met for a particular application by what is in 
the CTD Module 2 summary, the CTD Module 2 section would fulfill the need for an 
ISS/ISE.  In some cases, it will be convenient to write much of what is needed in the 
CTD Module 2 with appropriate appendices in Module 5.  In other cases, the ISS/ISE 
would be summarized in Module 2, with detailed reports in Module  5.  
 
Any questions about these matters can be raised with the reviewing division.  
 
 
Q11:   Microbiology Data  
 
The microbiology data will include both in vitro and in vivo studies. Where should the 
microbiology summary, overview, and study reports be included?  
 
A11:   The microbiology data from both in vitro and in vivo studies should be included with the 
Efficacy information. The summary information should be provided in the appropriate 
section 2.7 Clinical Summary and the reports should be filed in section 5.3.5.4 Other 
Study Reports.  
In addition, the microbiology information can be described in the Nonclinical sections as 
appropriate.  
 
 
Q12:   Clinical Variation  
 
For a clinical variation application, is it mandatory to submit a clinical overview and a 
clinical summary, or is it acceptable to submit either only an overview or only a 
summary? What are the parameters/conditions to be taken into account for choosing 
one or the other approach?  
 
A12:   Since variation is a term from the EU regulations, the answer should be provided by the 
EMEA.  
 
 
Q13:   Integrated Analysis of Efficacy (ISE) Section 2.7  Clinical Summary  Statistical 
Listings  
 
What approach should applicants take for the formatting and presentation of their 
integrated analyses when they have large amounts of statistical output to present 
(several thousands of pages)?  
 
A13:   As stated in section Reports of Analyses From More Than One Study 5.3.5.3, where the 
details of the analysis are too extensive to be reported in a summary document (for 
example, section Clinical Summary 2.7), they should be presented in a separate report. 
Such report should be placed in section 5.3.5.3.  
 
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  Contains Nonbinding Recommendations  
 
Q14:   Cross References/Cross Strings (in Paper Submissions)  
 
It is stated in the CTD that the section should be indicated in cross strings. What is 
meant here: The section number, or the section number and section name?  (The 
section name is in many cases too long to indicate in a cross string.)  
 
A14: 	  Providing the section header in addition to the section number improves the clarity of the 
reference, particularly for the uninitiated reader. To reduce the length of the cross string 
while maintaining the ease of use, it is recommended to include only the section number 
in the cross string and write the text so the reader will also know the section content. For 
example, ...as seen in the population PK study 101 (5.3.3.5) helps the reader to find the 
referenced study report under the Population PK Study Reports section. The text ...no 
safety problems were noted in the uncontrolled pneumonia study 101A (5.3.5.2) helps  
the reader find the referenced study report under the section Study Reports of 
Uncontrolled Clinical Studies for the Pneumonia indication.  
 
 
Q15:  	 Limitations of the Safety Database and Potential Implications  
 
Section 2.5 Clinical Overview and section 2.5.5 Overview of Safety both refer to an 
assessment of the limitations of the safety database but give few details on how to 
describe them. How should these limitations be described? In addition, there is no 
specific reference to any postmarketing steps the applicant can take to remedy those 
limitations. Where should a discussion of any postmarketing pharmacovigilance and 
other postmarketing study plans go?  
 
A15: 	  A fuller discussion of how to describe in the CTD the limitations of the safety database 
and the potential implications for the safety of the drug when marketed is as follows:  
 
 	  Nonclinical toxicology and safety pharmacology concerns, such as those arising from 
reproductive / developmental toxicity, carcinogenicity, hepatic injury, central nervous 
system injury, or effects on cardiac repolarization that are not fully resolved by 
available human data, or that arise from incomplete testing.  
 
 	  Limitations of human safety database, such as:  
o 	  Patient selection criteria that excluded people who are likely to be candidates for 
treatment in medical practice.  
o 	  Evaluations that were deficient for certain purposes (e.g., many drugs with 
sedative properties are not evaluated for effects on cognitive function in the 
elderly).  
o 	  Limited exposure of demographic or other subgroups, such as children, women, 
the elderly, or patients with abnormal hepatic or renal function.  
 
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  Contains Nonbinding Recommendations  
 	  Identified adverse events and potential adverse events that require further 
characterization or evaluation with respect to frequency and/or seriousness in the 
general population or in specific subgroups.  
 
 	  Important potential risks (e.g., known risks of pharmacologically related drugs) that 
require further evaluation.  
 
 	  Drug-drug interactions that have not been assessed adequately.  
Such information should be described and discussed in section 2.5.5 Overview of Safety, 
with appropriate cross references to section 2.7.4 Summary of Clinical Safety and any 
other relevant sections.  
A discussion of any planned postmarketing activity or study to address the limitations of 
the premarketing safety database should also be included in section 2.5.5 Overview of 
Safety, with any protocols for specific studies provided in section5.3.5.4 Other Clinical 
Study Reports or other sections as appropriate (e.g., module 4 if the study is a nonclinical 
study).  
An ICH guideline (E2E Pharmacovigilance Planning) is being developed to further 
address the question of how to describe the safety data and its limitations and how to 
describe planned postmarketing activities and studies.  
 
 
Q16: 	  Multiple Indications  
 
When submitting one dossier for multiple indications, how should the applicant 
present them in the clinical part of the registration dossier, for example sections 2.5 
Clinical Overview, 2.7.3 Summary of Clinical Efficacy, and 5.3.5 Reports of Efficacy 
and Safety Studies?  
 
A16: 	  One section 2.5 Clinical Overview is recommended for multiple indications to be 
registered along with development rationale and cross-referencing to the corresponding 
2.7.3 and 5.3.5 sections; the benefit/risk conclusions should support corresponding 

claimed indications.  

For section 2.7.3 Summary of Clinical Efficacy, in the case of more than one indication, 

the following organization is recommended as applicable. The current CTD numbering 

should be retained with identification of the indication, for example:  

2.7.3. UTI Summary of Clinical Efficacy 
 
2.7.3.1. UTI Background 
 
2.7.3.2. UTI Summary of Results of individual studies 
 
2.7.3.3. UTI comparison and analysis
  
2.7.3.3.1. UTI study population  

2.7.3.3.2. UTI Comparison of efficacy results 
 
2.7.3. Pneumonia Summary of Clinical Efficacy  

2.7.3.1. Pneumonia Background  

Other sections follow the same organization where applicable.
  
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  Contains Nonbinding Recommendations  
For section 5.3.5 Reports of Efficacy and Safety Studies, in case of more than one 
indication, the following organization is recommended as applicable. The current CTD 
numbering should be retained with identification of the indications, for example:  
5.3.5.UTI  
5.3.5.1. UTI Controlled studies  
5.3.5.2. UTI Uncontrolled studies  
5.3.5. Pneumonia  
5.3.5.1. Pneumonia Controlled studies  
5.3.5.2. Pneumonia Uncontrolled studies  

Other sections follow the same organization, where applicable.
  
 
 
Q17: 	  Narrative Descriptions  
 
The CTD guidance for Section Overall Safety Evaluation Plan and Narratives of 
Safety Studies 2.7.4.1.1 states that narrative descriptions for studies that contributed 
both efficacy and safety should be included in Section Summary of Results of 
Individual Studies 2.7.3.2 and only referenced in the safety section.  Please clarify 
whether the narrative to be included in 2.7.3.2 should include the safety results as well 
as enough detail to allow the reviewer to understand the exposure... and how safety 
data were collected or whether the results should be included in Section 2.7.4.1.1.  
  
A17:  	 In general, safety results should be described in section 2.7.4.1.1, because section 
Summary of Clinical Efficacy 2.7.3 is devoted to efficacy.  To avoid the need to describe 
the same study twice, section 2.7.3.2 asks for a reasonably complete description of 
studies pertinent to both safety and efficacy, including, in study narratives, information 
about the extent of exposure of study subjects to the test drug and how safety data were 
collected.  This approach is confirmed in section 2.7.4.1.1, which notes that narratives for 
studies contributing both safety and efficacy data should be included in section 2.7.3.2. 
As noted in section Background and Overview of Clinical Efficacy 2.7.3.1, however, any 
results of these studies that are pertinent to evaluation of safety should be discussed in 
section Summary of Clinical Safety 2.7.4.  
 
Q18:  	 According to ICH  E3 Structure and Content of Clinical Study Reports, the case report 
forms should be located in Appendix 16.3, the individual patient data listings in 
Appendix 16.4, and the publications and literature references in Appendices 16.1.11 
and 16.1.12 respectively.  The CTD organization provides locations for case report 
forms and individual patient data listings in Module 5.3.7 and for literature references 
in Module 5.4.  
 
Can clarity be provided as to where these items should actually be placed in CTD and 
the eCTD submissions?  
 
 
A18: 	  For paper submissions, case report forms and individual patient data listings should be 
located in Module 5.3.7, identified by study.  
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  Contains Nonbinding Recommendations  
 
For eCTD, PDF files for case report forms and individual patient data listings should be 
organized by study in the folder for Module 5.3.7.  However, in the index.xml file, the 
leaf elements for the case report forms and individual patient data listings should be 
included under the same heading as other study report files with additional information 
included with any accompanying study tagging file.  In addition, a repeat of the leaf 
element can be placed under the heading 5.3.7 Case Report Forms and Individual Patient 
Data Listings.  Datasets, if required by the region, should be organized according to 
regional guidance.  
 
For paper submissions, publications and literature references should be located in Module 
5.4.  
 
For eCTD, the files for publications and literature references should be located in the 
folder for Module 5.4.  However, in the index.xml file, the leaf elements for the 
publications and literature references should be included under the same heading as other 
study report files with additional information included with any accompanying study 
tagging file.  In addition, a repeat of the leaf element should be placed under the heading 
for 5.4 Literature References.  
 
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