Combination Products: Which Centre 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. An autoinjector, a prefilled syringe, a drug-eluting stent, an inhaler, a nasal spray.
The whole regulatory question is: which centre reviews it, and which body of rules applies. Get that wrong and you build a submission for the wrong agency.
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 → CDER leads.
- PMOA is the device → CDRH leads.
- PMOA is the biologic → CBER leads.
A lead centre does not mean the other centre is absent. It consults, and its requirements still apply to its component.
The Office of Combination Products (OCP) assigns the lead where it is not obvious.
When you cannot tell
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, and reasonable people disagree.
Where the PMOA is genuinely 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.
Do this early. The centre 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).
You are not required to run two parallel systems. Part 4 permits a streamlined approach: operate one system and add the specified provisions from 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.
The most 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. This is where combination product applications most often lose time, 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-labelled for use together.
How is the reviewing centre 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 centre. 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.