Time to Next Treatment (TTNT) is defined as the period from the start of the treatment to the start of the next line of treatment.
In lower-level incurable diseases, TTNT is a meaningful endpoint for those needing multiple treatment interventions to prolong survival. Unlike most disease-related endpoints, TTNT includes the time process of treatment tolerance and patient compliance.
TTNT becomes a measure of the duration of treatment effects, especially in primary cutaneous T-cell lymphoma.
Although TTNT is useful, it serves as a surrogate marker for the duration of clinical benefits and needs validation before it can be used as an independent marker for assessing treatment efficacy.