Categories: FDA, Medical Device

Upon learning that FDA had lost another round in its battle to classify Diphoterine® Skin Wash (DSW) as a combination product with a drug primary mode of action and that Prevor, DSW's manufacturer, was still fighting this issue nearly six years after it submitted its initial premarket notification for DSW, I turned into a five-year-old and kept asking why?

  • Why does FDA insists that a skin wash intended to "help prevent and minimize accidental chemical burn injuries" must be regulated as a drug but a drug-coated stent intended to improves arterial diameter is regulated as a device?
  • Why is making its product available in the US so important to Prevor that it is willing to continue to litigate this issue six years after it first tried to launch the product here?
  • Why is this issue still so difficult to resolve?

Not finding the answers in the opinions or the briefs, I went back to the beginning and looked at the legislative history behind Section 503(g) and the Safe Medical Devices Act.  And believe it or not, Congress intended for the SMDA to:

  • address the "difficulty under the present law in determining the jurisdictional base for regulating products that are comprised of a combination of drugs, devices or biologics."; and
  • "provide the Secretary with firm ground rules to direct products promptly to that part of the FDA responsible for reviewing the article that provides the primary mode of action of the combination product."

(p. 30  Sen Rep. 101-513).

It is obvious that that did not happen.  But why?  Because we made it too complicated.  In its simplest terms, the only difference between a drug and a device is how it does what it does. Therefore:

  • If it does not do it chemically, it is a device;
  • If it does it chemically it is a drug; and
  • If it does it both chemically and not chemically it is a COMBINATION PRODUCT.

Once I realized that, I realized both Prevor and FDA were making the issue harder than it is.  Both sides agree on the following

  • The product contains two constituents at most: the spray can and the liquid;
  • The liquid contributes the primary mode of action; and
  • The liquid has both a mechanical mode of action and a chemical mode of action.

The only issue they disagree about is whether the liquid is a drug or a device.  However, I think they are both wrong. It is a combination product; the water is the device and the diphoterine is the drug. (Another, and possibly better, way to look at the product as a whole is as a two constituent combination product, with the device constituent being the water-filled spray bottle which is combined with the drug constituent, the liquid diphoterine).

Looking at it either of these two ways leaves only one question left to ask:

  • Does DSW "help prevent and minimize accidental chemical burn injuries" primarily by:
    • mechanically washing the chemical from the skin or
    • by neutralizing the chemical?

This analysis avoids a lot of the complicated and thorny statutory construction issues litigated in this case and is consistent with prior FDA determinations.  For example, a drug coated stent has two constituents, one that mechanically improves arterial diameter and one that does so chemically.  Since the primary mode of the combination product is mechanical, a drug coated stent should be regulated by CDRH, which it is.

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