Last issue we looked at two Warning Letters from the June 2026 batch and identified the pattern: manufacturers relying on supplier certificates of analysis without doing their own testing, and quality units signing off on components with deficient specifications.
This issue, we're going deeper on one letter from that same batch -- because it introduces a dimension that many contract manufacturers and their clients don't think about until it's too late.
What happens when the FDA tells you that being a contractor doesn't protect you?
The Letter: Asanuma Corporation, Sagamihara Factory, Japan
Asanuma Corporation's Sagamihara Factory in Kanagawa, Japan manufactures OTC drug products for the U.S. market. On June 2, 2026, FDA issued a Warning Letter following a records review initiated by an August 25, 2025 request under section 704(a)(4).
FDA Warning Letter, issued June 2, 2026: Asanuma Corporation - Sagamihara Factory, 721136
The core violations were familiar -- the same two that appeared in the Revlon and PLZ Corp letters covered last issue:
Violation 1: Failed component identity and conformity testing (21 CFR 211.84(d)(1) and (d)(2))
Asanuma did not conduct identity testing on incoming components prior to use in manufacturing. They did not independently verify supplier COAs. Their component specifications were incomplete relative to current USP monograph requirements -- missing identification testing, assay requirements, and impurity limits. One specification for an impurity actually exceeded the USP limit.
Violation 2: Quality unit failed to exercise its responsibilities (21 CFR 211.22)
The quality unit approved and accepted components with deficient specifications. It did not ensure that test procedures were scientifically sound or aligned with current USP requirements.
So far, the same story as last issue.
But Asanuma's letter includes two things the others didn't.
What's Different This Time: Contractor Liability and an Import Alert
The FDA's Position on Contract Manufacturers
Buried in the Asanuma letter is a paragraph that every contract manufacturer and every brand owner who uses a contract manufacturer should read carefully:
The FDA's position is unambiguous. The letter includes a section titled "Responsibilities as a Contractor," and the language is direct: FDA regards contractors as extensions of the manufacturer, and states that you are responsible for the quality of drugs you produce as a contract facility "regardless of agreements in place with product owners." A quality agreement can allocate tasks between a contractor and a brand owner, but it cannot sign away the contractor's CGMP responsibility. FDA points contractors to its guidance document Contract Manufacturing Arrangements for Drugs: Quality Agreements for how to structure those relationships.
This matters because a significant portion of supplement and CPG manufacturing runs through contract facilities. Contract manufacturers sometimes assume that if the brand owner approved the product, the responsibility shifts to the brand. The Asanuma letter says plainly that it does not. Your facility's name is on the Warning Letter no matter whose product you were building.
The brand-owner side of this carries its own regulatory weight, though it comes from FDA's broader framework rather than this particular letter. Under FDA's position on own-label distributors, a brand that puts its name on a product carries its own responsibility for quality and cannot fully outsource that either. The practical result is that both parties carry obligations: the contractor cannot defer to the brand's approval, and the brand cannot assume the contractor has everything handled. But the Asanuma letter itself makes one point specifically, about the contractor: the responsibility is yours, and your agreement with the product owner does not reduce it.
The Import Alert
The Asanuma letter closes with a consequence that didn't appear in the other two: FDA placed all drugs imported from Asanuma's facility on Import Alert 66-40, effective January 9, 2026 -- months before the Warning Letter was even issued.
Import Alert 66-40 is FDA's mechanism for detaining products at the border without physical examination. Once a facility is on it, every shipment from that facility to the United States is presumed to be in violation until the manufacturer demonstrates otherwise and gets removed from the alert. Getting off an import alert is a lengthy, documented process that requires demonstrating sustained compliance over time.
For a contract manufacturer whose clients depend on U.S. market access, an import alert is not just a regulatory problem. It is a business-ending event for the relationships that matter most.
The Sequence Nobody Plans For
Reading the Asanuma letter alongside the previous month's batch reveals a pattern in how these situations develop. It almost never happens all at once.
It starts with a records request. FDA sends a 704(a)(4) request -- asking for documentation without showing up at the facility. The manufacturer responds. FDA reviews what was sent.
Then the back-and-forth begins. FDA asks follow-up questions. The manufacturer provides more documentation. What gets revealed in that exchange is often not intentional wrongdoing -- it's the gradual exposure of gaps that nobody thought were gaps: component testing that was assumed to be covered by the supplier's COA, specifications that nobody had compared to the current USP monograph in years, a quality unit that was technically reviewing documents but not catching what was missing.
By the time the Warning Letter arrives, FDA has already built a detailed picture of the facility's quality systems from the records the manufacturer provided. The Warning Letter is the conclusion of that analysis, not the beginning.
The import alert, in Asanuma's case, came even before the Warning Letter -- which means FDA had already seen enough in the records exchange to take enforcement action while the correspondence was still ongoing.
What This Means for Your Supply Chain
If you're a brand owner using contract manufacturers: your quality agreement is not your protection. Your protection is knowing what your contract manufacturer's quality systems actually look like -- not what their SOP says, but what their records can prove. At minimum, you should know whether they are conducting independent identity testing on incoming components, and whether their specifications are current relative to applicable USP monographs.
If you're a contract manufacturer: your clients' brand names are on the product, but your facility's name is on the Warning Letter. The FDA's contractor liability position means you cannot defer compliance to the brand owner's approval process. Your quality unit needs the authority and the tools to catch deficiencies before they show up in an FDA records review.
If you operate in either position: the sequence matters. These enforcement actions didn't start with an inspection. They started with a records request. The question isn't whether your facility could pass a walk-through -- it's whether your documentation can withstand scrutiny on paper, remotely, from an FDA reviewer who has never set foot in your building.
The Questions to Ask This Month
If you're a brand owner: Do you have visibility into your contract manufacturer's component testing records? Have you reviewed their specifications against current USP monographs? What does your quality agreement actually require them to document, and can they produce that documentation on request?
If you're a contract manufacturer: Does your quality unit have the resources and the authority to reject a component specification that doesn't meet USP requirements? Could you produce independent identity testing records for every incoming lot in the last 12 months? If FDA sent a records request tomorrow, how long would it take you to compile a response?
For both: Do you know which of your components are USP articles, and when you last verified that your specifications match the current monograph? USP monographs get updated. Specifications that were compliant five years ago may not be compliant today.
The Takeaway for This Issue
The Asanuma letter adds two things to the pattern we identified last issue: contractor liability is real and non-negotiable, and import alerts can happen before a Warning Letter is even issued.
For manufacturers whose business depends on U.S. market access, that sequence -- records request, back-and-forth, import alert, Warning Letter -- is the one to understand and avoid. The only effective defense is documentation that holds up before anyone asks for it.
A Note on This Series
We pull these letters directly from the FDA's public Warning Letter database, which updates continuously. Every letter we discuss is linked to its source so you can read the original in full. We don't wait for a monthly cycle -- when the FDA posts new letters with patterns worth examining, we cover them.
If you work in supplement, food, or cosmetics manufacturing and want to understand what FDA enforcement trends mean for your operation, this series is written for you.
Read Issue 1 of the Warning Letter Roundup →
Read Issue 3 of the Warning Letter Roundup →
See how BatchBuddy's COA Hub and quality unit documentation tools work →
Part of our 21 CFR Part 111 Requirements: The Complete Guide hub.