Document Headings

                    Document headings vary by document type but may contain                    the following:                  
                -                       the agency or agencies that issued and signed a document                    
                -                       the number of the CFR title and the number of each part                      the document amends, proposes to amend, or is directly                      related to                    
                -                       the agency docket number / agency internal file number                    
                -                       the RIN which identifies each regulatory action listed in                      the Unified Agenda of Federal Regulatory and Deregulatory                      Actions                    

                    See the                                          Document Drafting Handbook                                        for more details.                  

###### Department of Health and Human Services

###### Food and Drug Administration

          - [Docket No. FDA-2022-D-0113]

# AGENCY:

Food and Drug Administration, HHS.

# ACTION:

Notice of availability.

# SUMMARY:

The Food and Drug Administration (FDA or Agency) is announcing the availability of a draft guidance for industry entitled “Clinical Pharmacology Considerations for Human Radiolabeled Mass Balance Studies.” This draft guidance describes the FDA's recommendations regarding clinical pharmacology considerations for conducting human radiolabeled mass balance studies, including deciding whether and when to conduct the study, designing the study, and reporting results.

# DATES:

Submit either electronic or written comments on the draft guidance by August 3, 2022 to ensure that the Agency considers your comment on this draft guidance before it begins work on the final version of the guidance.

# ADDRESSES:

You may submit comments on any guidance at any time as follows:

### Electronic Submissions

Submit electronic comments in the following way:
      -  Federal eRulemaking Portal: https://www.regulations.gov.                      Follow the instructions for submitting comments. Comments submitted electronically, including attachments, to                      https://www.regulations.gov                      will be posted to the docket unchanged. Because your comment will be made public, you are solely responsible for ensuring that your comment does not include any confidential information that you or a third party may not wish to be posted, such as medical information, your or anyone else's Social Security number, or confidential business information, such as a manufacturing process. Please note that if you include your name, contact information, or other information that identifies you in the body of your comments, that information will be posted on                      https://www.regulations.gov. 
      - If you want to submit a comment with confidential information that you do not wish to be made available to the public, submit the comment as a written/paper submission and in the manner detailed (see “Written/Paper Submissions” and “Instructions”).

### Written/Paper Submissions

Submit written/paper submissions as follows:
      -  Mail/Hand Delivery/Courier (for written/paper submissions):                      Dockets Management Staff (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Rm. 1061, Rockville, MD 20852.                
      - For written/paper comments submitted to the Dockets Management Staff, FDA will post your comment, as well as any attachments, except for information submitted, marked and identified, as confidential, if submitted as detailed in “Instructions.”

*Instructions:*                     All submissions received must include the Docket No. FDA-2022-D-0113 for “Clinical Pharmacology Considerations for Human Radiolabeled Mass Balance Studies.” Received comments will be placed in the docket and, except for those submitted as “Confidential Submissions,” publicly viewable at                     *https://www.regulations.gov*                     or at the                           ( print page 26764)                        Dockets Management Staff between 9 a.m. and 4 p.m., Monday through Friday, 240-402-7500.                
      - Confidential Submissions—To submit a comment with confidential information that you do not wish to be made publicly available, submit your comments only as a written/paper submission. You should submit two copies total. One copy will include the information you claim to be confidential with a heading or cover note that states “THIS DOCUMENT CONTAINS CONFIDENTIAL INFORMATION.” The Agency will review this copy, including the claimed confidential information, in its consideration of comments. The second copy, which will have the claimed confidential information redacted/blacked out, will be available for public viewing and posted on https://www.regulations.gov.                      Submit both copies to the Dockets Management Staff. If you do not wish your name and contact information to be made publicly available, you can provide this information on the cover sheet and not in the body of your comments and you must identify this information as “confidential.” Any information marked as “confidential” will not be disclosed except in accordance with  21 CFR 10.20  and other applicable disclosure law. For more information about FDA's posting of comments to public dockets, see  80 FR 56469 , September 18, 2015, or access the information at:                      https://www.govinfo.gov/​content/​pkg/​FR-2015-09-18/​pdf/​2015-23389.pdf. 

*Docket:*                     For access to the docket to read background documents or the electronic and written/paper comments received, go to                     *https://www.regulations.gov*                     and insert the docket number, found in brackets in the heading of this document, into the “Search” box and follow the prompts and/or go to the Dockets Management Staff, 5630 Fishers Lane, Rm. 1061, Rockville, MD 20852, 240-402-7500.                

You may submit comments on any guidance at any time (see 21 CFR 10.115(g)(5)).

                    Submit written requests for single copies of the draft guidance to the Division of Drug Information, Center for Drug Evaluation and Research, Food and Drug Administration, 10001 New Hampshire Ave., Hillandale Building, 4th Floor, Silver Spring, MD 20993-0002. Send one self-addressed adhesive label to assist that office in processing your requests. See the                     **SUPPLEMENTARY INFORMATION**                     section for electronic access to the draft guidance document.                

# FOR FURTHER INFORMATION CONTACT:

                        Anuradha Ramamoorthy, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD 20903,                         *anuradha.ramamoorthy@fda.hhs.gov.*

# SUPPLEMENTARY INFORMATION:

## I. Background

FDA is announcing the availability of a draft guidance for industry entitled “Clinical Pharmacology Considerations for Human Radiolabeled Mass Balance Studies.” A human radiolabeled mass balance study is the single most direct method to obtain quantitative and comprehensive information on the absorption, distribution, metabolism, and excretion (ADME) of an investigational drug in the human body. The mass balance study can provide information to determine the overall pathways of metabolism and excretion of an investigational drug, identify circulating metabolites, and determine the abundance of metabolites relative to the parent or total drug-related exposure. This guidance provides FDA's recommendations for clinical pharmacology considerations in conducting human radiolabeled mass balance studies, including: (1) Deciding whether and when to conduct the study, (2) designing the study, and (3) reporting results.

This draft guidance is being issued consistent with FDA's good guidance practices regulation (21 CFR 10.115). The draft guidance, when finalized, will represent the current thinking of FDA on “Clinical Pharmacology Considerations for Human Radiolabeled Mass Balance Studies.” It does not establish any rights for any person and is not binding on FDA or the public. You can use an alternative approach if it satisfies the requirements of the applicable statutes and regulations.

## II. Paperwork Reduction Act of 1995

While this guidance contains no collection of information, it does refer to previously approved FDA collections of information. Therefore, clearance by the Office of Management and Budget (OMB) under the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3501-3521) is not required for this guidance. The previously approved collections of information are subject to review by OMB under the PRA. The collections of information for submission of investigational new drug applications in 21 CFR part 312 have been approved under OMB control number 0910-0014, and the collections of information for submission of new drug applications in 21 CFR part 314 have been approved under OMB control number 0910-0001.

## III. Electronic Access

                    Persons with access to the internet may obtain the draft guidance at either                     *https://www.fda.gov/​drugs/​guidance-compliance-regulatory-information/​guidances-drugs*,                     *https://www.fda.gov/​regulatory-information/​search-fda-guidance-documents*, or                     *https://www.regulations.gov.*

Dated: April 29, 2022.

Lauren K. Roth,

Associate Commissioner for Policy.

[FR Doc. 2022-09608 Filed 5-4-22; 8:45 am]

BILLING CODE 4164-01-P