Companion Diagnostics: LDTs Need Approval Too

Tuesday, June 26, 2012

It's been a couple weeks since I attended AMDM's FDA-Industry IVD Roundtable, but I've got one more nugget to share from that meeting. Looks like it'll be another few days until we're all chewing over the SCOTUS ACA ruling, so this is probably as good a time as any.

CBER's Andy Dayton was giving a presentation on companion diagnostics and a key question about the HIV drug Selzentry came up. It's not the first time FDA has been asked to clarify the position they took on this, but it might be the first time I've seen them comment publicly.

As avid readers may already be aware, Selzentry was allowed on the market with a labeling requirement for a 'highly sensitivie tropism assay' even though no such assay was (or has been) cleared or approved by FDA. It exists as an LDT offered by Monogram Biosciences, but under today's companion diagnostic rules, even gold standard tests aren't considered sufficient if they aren't cleared or approved. People bring up Selzentry/tropism all the time in the hopes that demonstrating FDA's historic inconsistency might lead to a change in policy or enforcement.

So Andy got the Selzentry question and prudently stated that he wasn't able to comment on the situation. OIVD's Liz Mansfield did decide to offer a comment, saying "The past is the past, and this won't happen again." Liz made it clear that if a drug depends on a test result for safe and effective use, FDA will be requiring the test to be cleared or approved even if it is delivered via a single clinical lab.

LDT "enforcement discretion" is still in effect broadly, but FDA has made many presentations over the last few years stating that enforcement discretion does not extend to referencing unapproved LDTs in new drug labeling. This poses a difficult situation for some highly proprietary markers like BRCA and FLT-3, but it sounds like FDA expects us to solve this problem or we will have difficult getting these drugs approved.

Tags: CDRH, CLIA, CoDx, FDA, Industry

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Glossary Terms

Association of Medical Device Manufacturers (AMDM)
Center for Biologics Evaluation and Research (CBER)
Gold standard
In Vitro Diagnostic (IVD)
Labeling
Laboratory Developed Test (LDT)
Office of In Vitro Diagnostic Devices (OIVD)