FDA Warning Letter targets Amphastar (NASDAQ: AMPH) IMS manufacturing facility

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What did Amphastar Pharmaceuticals (AMPH) disclose about the FDA Warning Letter?

Does the FDA Warning Letter require Amphastar’s IMS facility to stop production?

What corrective actions is Amphastar’s subsidiary IMS taking after the FDA inspection?

How might the FDA Warning Letter affect Amphastar Pharmaceuticals’ operations?

What specific issues did the FDA cite at Amphastar’s IMS facility?

Where can investors find more risk information about Amphastar (AMPH)?

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(Neutral)

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8-K

Amphastar Pharmaceuticals reported that its subsidiary, International Medication Systems, received an FDA Warning Letter on July 2, 2026 for its drug manufacturing facility in South El Monte, California. The letter follows a December 2025 FDA inspection and cites violations of current Good Manufacturing Practice regulations.

The observations relate to investigation procedures, environmental monitoring and handling procedures, and manufacturing equipment. IMS has not been directed to stop or restrict product from the facility or conduct a further recall, and it continues to manufacture while implementing a remediation plan and risk assessment requested by the FDA.

The company is evaluating the impact on its operations and acknowledges there is no assurance the FDA will be satisfied with its response. Until the deficiencies are resolved to the FDA’s satisfaction, additional regulatory or legal action may be taken without further notice.

None.

FDA Warning Letter and CGMP violations: A key subsidiary facility received an FDA Warning Letter citing current Good Manufacturing Practice violations, creating regulatory risk until deficiencies are fully resolved.
Potential for additional regulatory or legal action: The company warns that, until the FDA is satisfied with remediation, further regulatory or legal steps may be taken without additional notice.
Uncertain operational and financial impact: Amphastar is still evaluating how the Warning Letter may affect business operations, and offers no assurance on timing or outcome of FDA review.

FDA Warning Letter raises meaningful regulatory risk but no immediate shutdown.

Amphastar discloses that subsidiary IMS received an FDA Warning Letter tied to a December 2025 inspection of its South El Monte facility. The letter cites violations of current Good Manufacturing Practice involving investigations, environmental monitoring, handling procedures, and manufacturing equipment.

The FDA has not ordered IMS to cease or restrict products or to conduct an additional recall, and the facility continues operating while implementing corrective and remediation plans. However, the FDA requested an initial response within 15 working days, along with a risk assessment and remediation plan, indicating close oversight.

The company is still evaluating business impact and explicitly notes there is no assurance the FDA will be satisfied or how long resolution will take. Until deficiencies are resolved to the FDA’s satisfaction, further regulatory or legal action may occur without notice, so future company filings will be important to understand the status of remediation.

Item 8.01 — Other Events

1 item

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Warning Letter date: July 2, 2026 Inspection timing: December 2025 FDA response deadline: 15 working days +1 more

4 metrics

Warning Letter date July 2, 2026 Date FDA Warning Letter was received by IMS

Inspection timing December 2025 Month and year of FDA inspection preceding Warning Letter

FDA response deadline 15 working days Time requested for IMS’s initial response to FDA

Facility location South El Monte, California IMS drug manufacturing site cited in Warning Letter

Warning Letter, current Good Manufacturing Practice, FDA Form 483, forward-looking statements, +1 more

5 terms

Warning Letter regulatory

"received a warning letter (the "Warning Letter") from the FDA relating"

A warning letter is a formal notice from a government regulator saying a company has violated laws or rules, often about product safety, manufacturing, labeling, or marketing claims. Like a landlord’s official notice to fix a dangerous problem, it signals the company must correct issues or face fines, product holds, or reputational harm—risks that can delay sales, approvals, or damage share value, so investors watch them closely.

current Good Manufacturing Practice regulatory

"cites violations of current Good Manufacturing Practice ("CGMP") regulations"

Current good manufacturing practice (cGMP) are the up-to-date, enforced rules and standards that factories follow to make medicines, medical devices, and related products reliably safe and consistent. Think of it as a detailed recipe and factory checklist that covers cleanliness, equipment, staff training and record-keeping; meeting cGMP reduces the risk of recalls, regulatory shutdowns or lawsuits and thus protects product supply, company reputation and investor value.

FDA Form 483 regulatory

"issued inspectional observations at the conclusion of the inspection on an FDA Form 483"

forward-looking statements regulatory

"All statements in this that are not historical are forward-looking statements"

Forward-looking statements are predictions or plans that companies share about what they expect to happen in the future, like estimating sales or profits. They matter because they help investors understand a company's outlook, but since they are based on guesses and assumptions, they can sometimes be wrong.

risk assessment financial

"requests that IMS submit an initial response within 15 working days, conduct a risk assessment"

An evaluation of the possible things that could go wrong with an investment or business and how likely and severe those problems might be, covering factors like market swings, cash shortages, regulatory changes, or operational hiccups. Think of it like checking road conditions and fuel before a trip: it helps investors judge whether the potential reward is worth the chance of trouble, set appropriate prices or reserves, and plan steps to reduce or respond to losses.

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Understanding 8-K Material Events →

Available on EDGAR 07/08/2026 - 06:02 AM Accepted by SEC EDGAR 07/07/2026 - 08:03 PM

Amphastar disclosed that its subsidiary International Medication Systems received an FDA Warning Letter on July 2, 2026, for its South El Monte, California facility. The letter follows a December 2025 inspection and cites current Good Manufacturing Practice violations in investigations, environmental monitoring, handling, and equipment.

The Warning Letter does not direct IMS to cease or restrict products from the South El Monte facility or require an additional recall. IMS continues manufacturing and supplying products while implementing corrective and remediation actions in response to the FDA’s observations and requests.

IMS has implemented and continues to implement corrective actions addressing the FDA Form 483 and Warning Letter observations. It is preparing an initial response within 15 working days, performing a risk assessment, and developing a remediation plan as requested by the FDA to resolve cited deficiencies.

Amphastar states it is currently evaluating the impact of the Warning Letter on business operations. The company notes it cannot assure that the FDA will be satisfied with IMS’s response or predict timing, and additional regulatory or legal action may occur until issues are resolved satisfactorily.

The Warning Letter cites violations of current Good Manufacturing Practice regulations for finished pharmaceuticals. Observations involve investigation procedures, environmental monitoring and handling procedures, and manufacturing equipment at the IMS South El Monte facility, following inspectional observations recorded on FDA Form 483.

Risk factors are discussed in Amphastar’s SEC filings, including its Form 10-K for the year ended December 31, 2025, and Form 10-Q for the quarter ended March 31, 2026. These filings are available on Amphastar’s investor relations website and on the SEC’s EDGAR system.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event Reported): July 2, 2026

Amphastar Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in Charter)


Delaware	001-36509	33-0702205
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(I.R.S. Employer Identification Number)


11570 6th Street
Rancho Cucamonga, California	91730
(Address of Principal Executive Offices)	(Zip Code)

Registrant's telephone number, including area code: (909) 980-9484

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01. Other Events

On July 2, 2026, International Medication Systems, Limited (“IMS”), a subsidiary of the Company, received a warning letter (the "Warning Letter") from the FDA relating to IMS's drug manufacturing facility located in South El Monte, California. The Warning Letter follows an FDA inspection of the facility conducted in December 2025. The FDA issued inspectional observations at the conclusion of the inspection on an FDA Form 483.

The Warning Letter cites violations of current Good Manufacturing Practice ("CGMP") regulations for finished pharmaceuticals. The observations in the Warning Letter relate to investigation procedures, environmental monitoring and handling procedures, and manufacturing equipment. The Warning Letter does not direct IMS to cease or restrict products from the facility, nor does it require a further recall, although this is subject to third party verification. IMS continues to manufacture and supply products from the facility while implementing its remediation plan. The Warning Letter requests that IMS submit an initial response within 15 working days, conduct a risk assessment and submit a remediation plan.

The Company and IMS take the matters identified in the Warning Letter seriously. Since the conclusion of the inspection, IMS has implemented and is continuing to implement corrective actions in response to the Form 483 and Warning Letter. The Company is currently evaluating the impact of the Warning Letter on its business operations. The Company cannot, however, give any assurance that the FDA will be satisfied with IMS’s response or as to the timing of the resolution of the matters described in the Warning Letter. Until the deficiencies cited in the Warning Letter are resolved to the FDA's satisfaction, additional regulatory or legal action may be taken without further notice.

Forward-Looking Statements

All statements in this current report that are not historical are forward-looking statements, including, among other things, statements relating to the Company’s receipt of the Warning Letter, including potential corrective actions and resolutions, as well as any additional regulatory or legal action that could be taken against the Company. These statements are not facts but rather are based on the Company’s historical performance and our current expectations, estimates, and projections regarding our business, operations, and other similar or related factors. Words such as "may," "might," "will," "could," "would," "should," "anticipate," "predict," "potential," "continue," "expect," "intend," "plan," "project," "believe," "estimate," and other similar or related expressions are used to identify these forward-looking statements, although not all forward-looking statements contain these words. You should not place undue reliance on forward-looking statements because they involve known and unknown risks, uncertainties, and assumptions that are difficult or impossible to predict and, in some cases, beyond the Company’s control. Actual results may differ materially from those in the forward-looking statements as a result of a number of factors, including changes in laws and regulations and disruptions in supply chains as well as others described in the Company’s filings with the Securities and Exchange Commission, including in our Annual Report on Form 10-K for the year ended December 31, 2025, filed with the SEC on February 26, 2026, in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, filed with the SEC on May 7, 2026, and in our other filings or reports that we may file with the SEC. You can locate these reports through our website at http://ir.amphastar.com and on the SEC’s website at www.sec.gov. The forward-looking statements in this current report speak only as of the date of the report. The Company undertakes no obligation to revise or update information or any forward-looking statements in this current report to reflect events or circumstances in the future, even if new information becomes available or if subsequent events cause our expectations to change.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


	AMPHASTAR PHARMACEUTICALS, INC.
Date: July 8, 2026
	By:	/S/WILLIAM J. PETERS

		William J. Peters
		Chief Financial Officer, Executive Vice President and Treasurer

Source: View Original Filing on SEC EDGAR

Title of each class

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Name of each exchange on which registered

Common Stock, par value $0.0001 per share

The Nasdaq Stock Market LLC

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