The U.S. Food and Drug Administration issued a warning letter to St. Jude Medical Inc. for certain "nonconformities" in its manufacturing at the Atlanta plant where it creates the heart failure monitor CardioMEMS HF system.

In the letter dated Sept. 30, the FDA cited the company’s manufacturing, packing, storage, and other practices that are “not in conformity” with the current goods and manufacturing practice (CGMP) requirements.

In a regulatory report, St. Jude disclosed that the FDA inspected its Atlanta facility from June 8 to 26 and issued on July 6 a Form 483 identifying the observed non-conformities with CGMP.

The FDA cited the plant's failure to meet deadlines to sufficiently address concerns revolving around incorrect serial numbers, device surface coating defects, and validation of sterilization processes. 

According to St. Jude, it will continue to manufacture and ship CardioMEMS and other medical products from its Atlanta facility, and that customer orders are not expected to be affected while they deal with the FDA concerns.

The company, based in St. Paul, Minn., resolved a separate manufacturing issue in July 2014 involving its plant in Sylmar, Calif. It is warned by the FDA regarding serious violations – including failing to validate testing methods – in the plant where Durata leads used for implantable defibrillators are produced.

St. Jude’s shares were down at $63.80 in Friday’s extended trading.

CardioMEMS is a battery-free, permanently implanted sensor that is able to sense and transmit blood pressure readings from the pulmonary artery. The data provided are used by heart failure patients at home and provided to doctors, who may use the information to change or adjust medication.

The device, with a list price of $25,000, was approved by the FDA in May 2014 and has no competitor at present. In the second quarter of 2015 it generated $20 million in sales, higher by 18 percent than the first quarter.

St. Jude expects to rake in $85 million in CardioMEMS sales in 2015.