Another important issue is ensuring that low-volume tests are not impeded. Many tests will not be offered if device regulation applies, because the costs will be too great for the limited market. The Humanitarian Use Device program—the device analogue to orphan drugs—has a low ceiling: 4,000 patients tested per year.
There was broad agreement at the meeting that maintaining patient access to low-volume LDTs is important. Regulating LDTs for small populations will have unintended negative consequences. In many cases, companies would not offer IVDs because sales would be too low in comparison with the regulatory costs. The details of how the regulatory scheme would protect are unsettled.
A related concern is that once a product is cleared or approved, any significant modifications may trigger the need for a new FDA clearance or approval. LDTs are often modified. This may result from new technology, enhanced clinical understanding of the disease, new biomarkers, improved bioinformatics, or evolving diseases.
IVD kit companies sometimes defer making improvements because of the costs and time needed to go through the regulatory process. Applying the same model to LDTs could level the playing field but also delay or prevent beneficial improvements in the test.