The FDA proposed reclassifying certain companion diagnostic assays—specifically nucleic acid‑based tests used with oncology therapeutics—from Class III down to Class II, subject to 510(k) premarket notification and special controls. The agency cited decades of PMA data, mature technology, and a lack of significant postmarket safety signals as justification. If finalized, the reclassification would lower regulatory burden and shorten review timelines for manufacturers, potentially increasing competition and patient access to companion diagnostics. The proposal covers tests using amplification and sequencing technologies to detect actionable genetic variants for approved cancer drugs. Stakeholder comments are open until Jan. 26, 2026; labs, diagnostics firms and advocacy groups are expected to submit views on performance standards, postmarket surveillance, and implications for clinical validity and reimbursement.