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

###### Food and Drug Administration

          - [Docket No. FDA-2020-D-1794]

# 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The Food and Drug Administration (FDA or Agency) is announcing the availability of a draft guidance for industry entitled “Evaluation of Gastric pH-Dependent Drug Interactions With Acid-Reducing Agents: Study Design, Data Analysis, and Clinical Implications.” This draft guidance focuses on specific recommendations pertinent to gastric pH-dependent drug-drug interaction (DDI) assessment and describes the FDA's recommendations regarding when clinical DDI studies with acid-reducing agents (ARAs) are needed; design of the clinical studies; interpretation of study results; and communicating findings and options for managing pH-dependent DDIs in product labeling.

# DATES:

Submit either electronic or written comments on the draft guidance by March 1, 2021 to ensure that the Agency considers your comment on this draft guidance before it begins work on the final version of the guidance.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-2020-D-1794 for “Evaluation of Gastric pH-Dependent Drug Interactions With Acid-Reducing Agents: Study Design, Data Analysis, and Clinical Implications.” 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 Dockets Management Staff between 9 a.m. and 4 p.m., Monday through Friday.                
      - 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.                

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., Bldg. 51, Rm. 3118, Silver Spring, MD 20993, 240-402-6426.

# SUPPLEMENTARY INFORMATION:

## I. Background

                    FDA is announcing the availability of a draft guidance for industry entitled “Evaluation of Gastric pH-Dependent Drug Interactions With Acid-Reducing Agents: Study Design, Data Analysis, and Clinical Implications.” ARAs such as antacids, histamine H2-receptor antagonists, and proton pump inhibitors are widely used, and many of these drugs are available over-the-counter. Because ARAs can elevate the gastric pH, concomitant administration of a drug with an ARA could alter the solubility, dissolution, and bioavailability of the drug, potentially resulting in a loss of efficacy for weak-base drugs or increased toxicity for weak-acid drugs. Therefore, it is important to assess the susceptibility of an investigational drug to gastric pH change-mediated DDIs early in drug development, characterize the DDI effect with clinical studies when needed, and communicate the findings in the drug product labeling. This draft guidance addresses when clinical DDI studies with ARAs should be conducted, the design and conduct of clinical pH-                          ( print page 77223)                        dependent DDI studies, alternative approaches for evaluating pH-dependent DDIs, and extrapolating clinical DDI study results with drug classes of ARAs.                

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 “Evaluation of Gastric pH-Dependent Drug Interactions With Acid-Reducing Agents: Study Design, Data Analysis, and Clinical Implications.” 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 submissions of investigational new drug applications, new drug applications, and biologic license applications in 21 CFR parts 312, 314, and 601 have been approved under OMB control numbers 0910-0014; 0910-0001; and 0910-0338, respectively. In addition, the submission of prescription drug labeling under 21 CFR 201.56 and 201.57 has been approved under OMB control number 0910-0572.

## 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*                     or                     *https://www.regulations.gov.*

Dated: November 25, 2020.

Lauren K. Roth,

Acting Principal Associate Commissioner for Policy.

[FR Doc. 2020-26510 Filed 11-30-20; 8:45 am]

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