News|Videos|April 23, 2026

Ask the Expert: Investigating Patient Complaints About Combination Products

Susan J. Schniepp, distinguished fellow at Nelson Labs, and Siegfried Schmitt, PhD, vice president, Technical at Parexel, discuss how companies can investigate patient complaints involving prefilled syringes and combination products.

Ask the Expert Video Series

Welcome to the Ask the Expert video series. This series is an extension of the PharmTech Group’s long-running print column in which industry experts answer common quality and regulatory questions from the industry. Have a question you would like answered? Send it to PTProjects@mmhgroup.com, and it may appear in a future episode or print column.

In this episode of Ask the Expert, Susan J. Schniepp, distinguished fellow at Nelson Labs, and Siegfried Schmitt, PhD, vice president, Technical at Parexel, address the complexities of investigating patient complaints regarding pre-filled syringe (PFS) and combination products. Schniepp and Schmitt make it clear; for manufacturers who purchase commercial syringes for their drug products, the marketing authorization holder (MAH) remains ultimately responsible for product performance, regardless of their level of control over the component manufacturer.

Investigating these types of events comes with complications, such as the lack of physical evidence (eg, returned devices, photos, or videos) when products are self-administered at home. While the rise of home-administered medications like GLP-1s has tempted some firms to cite “human error” as a root cause, manufacturers must ensure devices are “fit for purpose” across diverse populations, including the elderly and those with disabilities. If real-world evidence reveals a performance gap, it may indicate that initial usability testing may not have been sufficiently varied or robust.

There are also limitations with traditional corrective and preventive actions and recall procedures for these types of complaints. Identifying specific patients for recalls is often impossible once a product is dispensed, and privacy laws, such as HIPAA in the United States, can hinder a manufacturer’s ability to gather critical patient-specific investigation data. Furthermore, responding to patient complaints requires different language than communicating with healthcare professionals to ensure the investigation's logic is understood.

To manage these risks, the experts stress the importance of highly granular quality agreements. These agreements must move beyond simple checklists to explicitly define which party takes the lead in investigations, preventing a “blame culture” between drug manufacturers and component suppliers. Finally, companies must regularly revisit complaint procedures to adapt to evolving business environments, such as direct-to-patient shipping, to ensure they can effectively defend their “effectiveness checks” during regulatory inspections.

Watch the video to find out how Sue and Siegfried answer the question, “My company got a complaint from a patient that their prefilled syringe failed to inject. We make the drug product and purchase the syringe. How do we investigate a problem with the commercial syringe component that we used?”

About the Experts

Susan J. Schniepp is distinguished fellow at Nelson Labs and a member of PharmTech’s Editorial Advisory Board.

Siegfried Schmitt, PhD, is vice president, Technical at Parexel and a member of PharmTech’s Editorial Advisory Board.


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