ProRx LLC — FDA Warning Letter (April 7, 2026)

You registered your facility with the U.S. Food and Drug Administration (FDA) as an outsourcing facility under section 503B of the Federal Food, Drug, and Cosmetic Act (FDCA) [21 U.S.C. § 353b]1 on April 27, 2022, and most recently on February 20, 2026. From September 9, 2025, to September 19, 2025, an FDA investigator inspected your facility, ProRx LLC, located at 619 Jeffers Cir, Exton, PA 19341. During the inspection, the investigator noted that drug products you produced failed to meet the conditions of section 503B of the FDCA necessary for drugs produced by an outsourcing facility to qualify for exemptions from certain provisions of the FDCA. In addition, the investigator noted serious deficiencies in your practices for producing drug products intended or expected to be sterile, which put patients at risk.

Under section 503B(b) of the FDCA, a compounder can register as an outsourcing facility with FDA. Drug products compounded by or under the direct supervision of a licensed pharmacist in an outsourcing facility qualify for exemptions from the drug approval requirements in section 505 of the FDCA [21 U.S.C. § 355(a)], the requirement in section 502(f)(1) of the FDCA [21 U.S.C. § 352(f)(1)] that labeling bear adequate directions for use and the Drug Supply Chain Security Act requirements in section 582 of the FDCA [21 U.S.C. § 360eee-1] if the conditions in section 503B of the FDCA are met.2

An outsourcing facility, which is defined in section 503B(d)(4) of the FDCA [21 U.S.C. § 353b(d)(4)], is a facility at one geographic location or address that — (i) is engaged in the compounding of sterile drugs; (ii) has elected to register as an outsourcing facility; and (iii) complies with all of the requirements of this section. Outsourcing facilities must comply with other applicable provisions of the FDCA, including section 501(a)(2)(B) [21 U.S.C. § 351(a)(2)(B)], regarding current good manufacturing practice (CGMP), and section 501(a)(2)(A) [21 U.S.C. § 351(a)(2)(A)], regarding insanitary conditions. Generally, CGMP requirements for the preparation of drug products are established in Title 21 of the Code of Federal Regulations (CFR) parts 210 and 211.

In addition, for a drug product compounded using bulk drug substances to qualify for the exemptions under section 503B, the bulk drug substances that are used must appear on a list established by the Secretary identifying bulk drug substances for which there is a clinical need (“503B bulks list”), or the compounded drug must appear on the drug shortage list in effect under section 506E of the FDCA at the time of compounding, distribution, and dispensing (section 503B(a)(2)(A) of the FDCA [21 U.S.C. § 353b(a)(2)(A)]).

In addition, for a compounded drug product to qualify for the exemptions under section 503B, the labeling of the drug must include certain information (section 503B(a)(10) of the FDCA [21 U.S.C. §353b(a)(10)]).

Further, for a compounded drug product to qualify for the exemptions under section 503B, it must be compounded in an outsourcing facility that is in compliance with the registration and reporting requirements in section 503B(b), including the requirement to submit adverse event reports to FDA “in accordance with the content and format requirements established through guidance or regulation under section 310.305 of title 21, Code of Federal Regulations (or any successor regulations)” (section 503B(a)(1), (b)(5) of the FDCA [21 U.S.C. § 353b(a)(1), (b)(5)]).

During the inspection, the FDA investigator noted that drug products produced by your facility failed to meet the conditions of section 503B. For example, the investigator noted:

1. Your facility compounded drug products using tirzepatide bulk drug substance. For example, on (b)(4), your facility compounded (b)(4) vials of Tirzepatide 72MG/4ML injectable drug product and on (b)(4), your facility compounded (b)(4) vials of Tirzepatide 45MG/2.5ML injectable drug product, using tirzepatide bulk drug substance on both dates. These drug products compounded using tirzepatide bulk drug substance are not eligible for the exemptions provided by section 503B because tirzepatide does not appear on the 503B bulks list and was not used to compound a drug that appears on FDA’s drug shortage list at the time of compounding, distribution, and dispensing (section 503B(a)(2)(A).3