FDA Downgrades Oncology ISH Test Systems to Class II
The agency's final order shifts certain in situ hybridization devices from premarket approval to the 510(k) pathway.
The Food and Drug Administration has finalized a reclassification of in situ hybridization (ISH) test systems used with approved oncology therapeutics, moving them from Class III to Class II.
The agency determined that special controls are sufficient to provide reasonable assurance of safety and effectiveness for this device type, establishing a new classification regulation to that end.
The agency noted that a 510(k) typically results in a faster review than a PMA, which should ultimately provide patients with more timely access to these companion diagnostic devices.
The final order follows a proposed rule published in June 2025, which drew supportive comments from fewer than five stakeholders, primarily from the medical device industry. While commenters generally backed the reclassification, some offered recommendations for clarity regarding device descriptions and labeling requirements, which the FDA addressed in its responses.