Combination Products: Which Center Reviews You, and Why It Matters
A combination product is made of two or more regulated components: a drug and a device, a biologic and a device, or all three. Examples include autoinjectors, prefilled syringes, drug-eluting stents, inhalers and nasal sprays.
The first regulatory question is which center leads the review, and which rules apply. Get that wrong and you build a submission for the wrong center.
Primary mode of action
Assignment turns on the primary mode of action (PMOA): the single mode of action expected to make the greatest contribution to the product's intended therapeutic effect.
- PMOA is the drug, and CDER leads.
- PMOA is the device, and CDRH leads.
- PMOA is the biologic, and CBER leads.
The other center consults, and its requirements still apply to its component.
The Office of Combination Products (OCP) assigns the lead where it is not obvious.
Unclear PMOA
An autoinjector is usually straightforward: the drug does the work, the device delivers it, CDER leads. A drug-eluting stent is not: the stent holds the vessel open and the drug prevents restenosis, so the PMOA is arguable.
Where the PMOA is unclear, file a Request for Designation (RFD) with OCP. FDA responds within 60 days, and the assignment binds unless both sides agree to change it.
File early: the center determines the application type, the evidence expected, the user fee and the review clock.
The cGMP rule
21 CFR Part 4 governs manufacturing. A combination product must satisfy both the drug cGMPs (21 CFR 210 and 211) and the device quality system regulation (21 CFR 820).
Part 4 does not require two parallel systems. It permits a single-system approach: operate one and add the specified provisions of the other. If your base is the drug cGMPs, you add device design controls, purchasing controls, CAPA, and installation and servicing. If your base is the quality system regulation, you add the drug provisions for testing, stability and expiry.
A common gap is a pharma sponsor with no design history file and no design controls, because it has never had to build one.
Human factors
If a patient or caregiver operates the delivery mechanism, expect human factors validation to be part of the submission. Combination product applications often lose time here, and it appears in Complete Response Letters for emergency-use products alongside clinical deficiencies.
Frequently asked questions
What is a combination product?
A product made of two or more regulated components, such as a drug and a device, that are physically combined, co-packaged, or cross-labeled for use together.
How is the reviewing center decided?
By primary mode of action, the component expected to make the greatest contribution to the therapeutic effect.
What is a Request for Designation?
A formal submission to the Office of Combination Products asking FDA to assign the lead center. FDA responds within 60 days.
Do I have to comply with both drug and device GMPs?
Yes, but 21 CFR Part 4 permits a streamlined system: operate one and add the specified provisions of the other rather than running two.
Which provisions get added most often?
Design controls, purchasing controls and CAPA, when a drug manufacturer takes on a device component for the first time.
Does a prefilled syringe need human factors validation?
If a patient or caregiver administers it, plan for it. FDA expects validation covering the critical tasks a user performs.