FDA Eases Approval Path for Certain Cancer Companion Diagnostic Tests

The FDA has reclassified certain in situ hybridization tests used with approved cancer therapies from Class III to Class II, allowing them to use the 510(k) premarket notification pathway while remaining subject to special controls. Roman Zaiets/Shutterstock

The U.S. Food and Drug Administration has issued a final order moving certain laboratory tests used to help guide treatment with approved cancer drugs from Class III to Class II, changing the premarket pathway manufacturers must follow. The change, published in the Federal Register and effective September 16, 2026, moves in situ hybridization (ISH) test systems — tools used alongside approved cancer treatments — from the most stringent device regulatory category to a less burdensome one.

Certain Cancer Diagnostic Tests Move From Class III to Class II