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AB Rated 505(b)(2)’s

Can you have an “AB” rated 505(b)(2)?  Yes, as well as other Therapeutic Equivalent (TE) codes that are most often associated with the TE codes for generics in the Orange Book.

Several years ago when I was speaking about the potential products that qualified under 505(b)(2) I had a line in a PowerPoint slide for “AB” rated drugs.  People saw that line and started thinking: ‘how that can be?’ and distracted them from the rest of the slide and my talk.  I dropped that line from most of my future presentations.  In fact, the possibility for a therapeutic equivalent is usually thought to be limited to injectables.  As the reader knows, a generic usually can have excipients different than the RLD, except for injectables.  Here are a couple of examples of 505(b)(2)s that appear in the Orange Book:

Product NDA Dosage Form Difference from RLD
Pamidronate Disodium 021113 (3/04/2002) Injectable RLD is crystalline powder, this a solution with different API form and pH adjuster (see p. 19/70)
Fluorescein Sodium 022186 (8/8/2008 Injectable 2 RLDs: One same as discontinued, the other different volume (see pp. 37-38/65)
Nicardipine HCl 022276 (7/24/2008) Injectable Different quality and quality of excipients than RLD (see  p. 5/39); NaCl instead of sorbitol, benzoic acid instead of citric acid.

Abbott Laboratories, producer of AndroGel™, has recently filed a Citizen Petition to prevent FDA from granting a TE to a competing testosterone gel.  What precipitated this is that FDA decided that residual testosterone on the skin from testosterone gel products had the potential to transfer to a female partner and that future generics would need to conduct skin-transfer, hand-washing and perhaps shower studies. Such studies are beyond the scope of a 505j application and thus, FDA determined that 505(b)(2) was the correct pathway.  Abbott doesn’t challenge this determination, rather, it is worried that the assignment of a TE code would allow substitution at the pharmacy level, much like a generic.

In the past, FDA has treated the Orange Book and the TE codes as advisory and not subject to normal rule making.  Abbott wants to change this so that there is a means to challenge the listings.