What defines treatment-emergent signs and symptoms (TESS) according to the FDA?

Treatment-emergent signs and symptoms (TESS) are specifically defined as any adverse events that arise during treatment which were not present at baseline, as well as any events that were already present but worsened in severity after the initiation of treatment. This comprehensive definition allows clinicians and researchers to identify the new adverse effects that may be associated with a treatment and to monitor any exacerbation of pre-existing conditions.

The inclusion of both categories—newly occurring events and worsening of existing ones—ensures a full understanding of the safety profile of a treatment as it acknowledges both the emergence of new symptoms that could be attributable to the treatment as well as the potential for existing conditions to deteriorate. This dual focus is critical for assessing the overall impact of a treatment on patient health and safety.

Thus, identifying TESS as encompassing both categories aligns with the FDA's standards for safety monitoring in clinical trials, making this definition essential for accurate data interpretation and regulatory compliance.