Table 2.

Proposed standardisation of the definition of time to next treatment (TTNT) for use in future clinical studies of primary cutaneous T-cell lymphomas (CTCL).

	Defined Parameters
Measurement	TTNT is measured from the date of initiation (first dose) of treatment, to the date of initiation of the next line of therapy.
Exclusions	“Next line of therapy” excludes skin-directed therapies including topical steroids, nbUVB/PUVA, or focal radiation where less than 50% of the skin area is irradiated. Note: the cut-off of 50% is arbitrary but consistent with prior definitions of DOCB [9,10].
No subsequent lines of anti-CTCL therapy	For patients who are not fit for active management (due to co-morbidities and/or poor performance state), or those who decline further anti-CTCL treatment, the “next line of therapy” is recorded from the date of commencement of “end-of-life care” [47] and/or the withdrawal of all anti-CTCL therapies.
Censoring	Patients who have not progressed to a subsequent line of therapy, will be censored at the date of last follow up or at death.
Short-term treatment gaps	Short-term treatment gaps within the one course of prescribed therapy do not trigger a “next line of therapy”, provided no progression of disease occurs during the during treatment break. Short-term treatment gaps are defined as treatment withheld for duration < 2 months, for the following reasons: intercurrent illness, lack of treatment availability, for relief of toxicities, or patient preference. For treatment gaps ≥ 2 months, re-commencement of therapy will constitute a subsequent line of therapy, thus triggering an event in the TTNT and re-starting the “TTNT clock”.
Maintenance therapies	Commencement of pre-planned consolidation/maintenance anti-CTCL therapy in a patient with controlled disease will not trigger a TTNT event.
Allogeneic transplantation	For patients undergoing allogeneic transplantation, TTNT is triggered at the date of commencement of the conditioning therapy. If TSE is incorporated pre-transplant, then the date of commencement of TSE should be the time point used to trigger the TTNT.
Prospective clinical trials	In the context of prospective clinical trials, data collection should be continued beyond the date of disease progression, to include the date of initiation of the next line of anti-CTCL therapy.

DOCB = duration of clinical benefit; nbUVB/PUVA = narrowband UVB phototherapy and psoralen-UVA photochemotherapy; TSE = total skin electron therapy.