The KPV discussion followed many of the same themes as the earlier discussion on BPC-157, but with even greater focus on identity, product quality, dosing uncertainty, and the limits of FDA’s authority under Section 503A.
KPV is a small synthetic peptide composed of three amino acids—lysine, proline, and valine. It corresponds to a fragment of alpha-MSH, an endogenous peptide involved in inflammatory signaling. FDA acknowledged that peptide size is relevant, explaining that “there is less concern for a peptide with fewer amino acids,” while cautioning that even a small peptide still depends on a controlled and well-understood manufacturing process.
FDA’s presentation centered on the withdrawn nomination, which was inconsistent as to whether KPV free base or KPV acetate had actually been nominated. Per FDA, the certificate of analysis did not clearly align with the identified substance, and FDA cited missing information concerning impurities, aggregates, microbial limits, formulation, human exposure, safety, effectiveness, and historical use in compounding.
The agency repeatedly returned to nomenclature as a foundational problem. FDA stated that “KPV” is a common name rather than a recognized United States Adopted Name and that use of the USAN process would help resolve uncertainty over exactly which substance is being prepared and administered. As one FDA representative put it, “We wish the industry would avail itself to the USAN process. It would solve that identity problem.”
Committee members connected that uncertainty to reproducibility. Even accepting reports of meaningful patient benefit, they questioned whether another pharmacy or clinician could reproduce the same substance, formulation, dose, and result. One member described the vote as feeling like a “black box” because the Committee could not clearly identify what product would ultimately be compounded if KPV were added to the list.
One physician expanded on that concern, noting that KPV is already being used in injectable, oral, nasal, topical, and other formulations. He asked how physicians determine the appropriate dose, route of administration, frequency, formulation, or drug holiday in the absence of fundamental drug-development pharmacology. "Are they guessing?" he asked.
Ironically, the audiovisual feed cut out just as FDA began responding to that question. Once the audio returned, FDA explained that the available nonclinical studies are exploratory and do not establish exposure-response relationships, effective dosing, safety margins, treatment frequency, or duration. One FDA representative acknowledged that "there's absolutely no basis for us to determine what dose is to be given" and concluded that, at this stage, prescribing becomes "a little bit of guesswork."
FDA expressed similar concern about oral and other formulations. Agency representatives noted that many peptides have extremely limited oral bioavailability, yet oral peptide products continue to be offered. The broader point was repeated several times: once a substance is placed on the Bulks List, the box is open. FDA may specify a route limitation in the listing, but absent an express restriction, pharmacies may compound the substance in different routes and dosage forms. Section 503A does not provide a mechanism for FDA to impose one uniform finished-product formulation, designated supplier, release specification, or clinical dosing protocol across every 503A pharmacy, although the API must still satisfy the applicable federal sourcing and certificate-of-analysis requirements.
That was also FDA’s answer to many of the proposed guardrails. Public commenters outlined a detailed quality framework: qualified API sourcing; independent third-party lot testing for identity, potency, purity, related substances, residual solvents, elemental impurities, TFA, sterility, endotoxins, and microbial limits; enhanced controls for sterile products; identification of the API manufacturer and compounding pharmacy; physician monitoring and adverse-event reporting; and complete lot-level chain-of-custody documentation.
One physician summarized the concern directly: “The most probable source of patient harm is product quality—misidentification, impurities, and contamination.”
A domestic manufacturer reported results from its testing of seven KPV products obtained from the research-use-only market. According to the testimony, none came within 10% of labeled potency, one contained approximately 30% unidentified material, and another contained nearly 2% TFA. The witness stated that “every one of these market products would have been rejected and never shipped” under the release standards he described.
That testimony should not be read as a conclusion about every RUO or direct-to-consumer model. It demonstrates the importance of verifiable standards regardless of distribution method: reliable sourcing, defined specifications, appropriate testing, transparent quality controls, and accountability throughout the supply chain.
FDA’s response, however, was that many of those safeguards cannot be imposed uniformly through the current 503A framework. The agency stated that it lacks statutory or regulatory authority to require 503A pharmacies to register with FDA, report adverse events, disclose what substances they compound, source API domestically, or comply with many of the sourcing and reporting conditions proposed during public comment. State boards of pharmacy remain primarily responsible for the day-to-day oversight of 503A pharmacies, although FDA may conduct surveillance and for-cause inspections and coordinate with state regulators.
This is where the KPV debate became especially difficult. Commenters argued that quality risks could be addressed through defined standards. FDA responded that, once the substance is listed, it does not have the authority to guarantee that every compounder will follow those proposed standards. In FDA’s view, listing is not a narrow authorization of one carefully controlled product. It may open the door to multiple sources, formulations, routes, and practices that the agency cannot routinely monitor.
FDA also raised a theoretical immunogenicity concern. An immune response to KPV could potentially generate antibodies that cross-react with an endogenous peptide counterpart, including potentially the corresponding portion of alpha-MSH, and interfere with its natural activity. FDA acknowledged that a three-amino-acid peptide would generally present less concern than a much larger peptide, but it could not conclude that the risk is absent. The risk may depend on manufacturing quality, impurities, aggregation, excipients, and the final formulation.
Physicians, meanwhile, described existing clinical use in patients with inflammatory bowel disease, irritable bowel syndrome, inflammatory skin conditions, wound-healing concerns, and mast-cell-related disorders. One physician stated that his practice had observed benefits in “gastrointestinal illness, in irritable bowel syndrome, and inflammatory bowel disease,” and added that “in our hands, this has been a very safe peptide.”
As with BPC-157, members questioned why FDA continued to rely on deficiencies in a withdrawn nomination when additional characterization, dispensing, and safety information had later been submitted. FDA explained that its briefing package reflected the information available when the review was completed and that thousands of pages of later public comments could not be fully evaluated within the available time and resources. FDA emphasized that comments received by the Committee deadline were provided to the Committee and that comments submitted by the close of the docket would be considered as the agency continued its review and any subsequent rulemaking.
The central tension was therefore not simply whether KPV shows promise or whether stronger quality standards would be beneficial. It was whether FDA should place KPV on the list knowing that, once the box is open, the agency has limited authority to control every product, source, route, formulation, dose, or quality system that may follow.
Ultimately, the Committee voted 8–6 in favor of recommending that KPV be added to the 503A Bulks List.