Answer

These can be cited with other research products as per a 2017 NIH notice about this:

Citing interim research products in applications, proposals and reports

Interim research products can be cited anywhere other research products are cited. These sections include the following:

• R&R Other Project Information Form, Bibliography & References Cited
• R&R Senior/Key Person Profile (Expanded) Form, Biographical Sketch
• PHS 398 Research Plan, Progress Report Publication List
• PHS 398 Career Development Award Supplemental Form, Progress Report Publication List
• PHS Fellowship Supplemental Form, Progress Report Publication List
• RPPR, section C - Products

To cite the product, applicants and awardees must include the Digital Object Identifier and the Object type (e.g. preprint, protocol) in the citation. Also list any information about the document version (e.g. most recent date modified), and if relevant, the date the product was cited.

Example: Bar DZ, Atkatsh K, Tavarez U, Erdos MR, Gruenbaum Y, Collins FS. Biotinylation by antibody recognition- A novel method for proximity labeling. BioRxiv 069187 [Preprint]. August 11, 2016 [cited 2017 Jan 12]. Available from: https://doi.org/10.1101/069187.

These requirements help reviewers understand that the product is public, interim, and identify the specific version is being referenced.

Note: Applicants are responsible for providing the information necessary to review a section of an application within the page limits of that section.