NCT05311085.

Study name	Cytisine and e‐cigarettes with supportive text‐messaging for smoking cessation (Cess@Tion)
Methods	RCT Setting: Community University of Auckland, New Zealand
Participants	Estimated enrolment: 800 Inclusion criteria: Daily smokers who live in New Zealand; motivated to quit smoking within the next two weeks & willing to use cytisine or an EC or both products; ≥ 18 years Exclusion criteria: another person in their household currently enrolled in the study; pregnancy/breastfeeding; using smoking cessation medication (including EC daily for the last month); hypersensitivity to cytisine or nicotine EC; health condition e.g. renal impairment; tuberculosis; myocardial infarction, stroke, or severe angina, high BP, seizures; strong preference to use or not to use cytisine and/or EC in their quit attempt For a full list see NCT record.
Interventions	EC: Pod device. Nicotine strength: 30 mg/mL (3%). Flavour: Tobacco. Brand name: UpOx Cytisine Arm 1: Monotherapy (Cytisine only) 12 weeks of cytisine: Participants allocated cytisine will be instructed to follow the manufacturer's 25‐day dosing regimen, then follow a maintenance dose of cytisine from day 26 to week 12. Participants will also receive 6 mths of text‐based smoking cessation support. Cytisine. Brand name: Tabex. Standard dosing of: days 1‐3: one tablet (1.5 mg) every two hours through the waking day (six tablets/day) days 4‐12: one tablet every 2.5 hours (five tablets/day). Quit smoking date is day five. days 13‐16: one tablet every three hours (four tablets/day) days 17‐20: one tablet every 4‐5 hours (three tablets/day) days 21‐25: one tablet every six hours (two tablets/day) Followed by a maintenance dose of cystine from day 26 to week 12 (one tablet every six hours: two tablets/day) Arm 2: Monotherapy (Nicotine EC only) 12 weeks of a nicotine EC. Participants will also receive six months of text‐based smoking cessation support. Arm 3: Combination therapy (Cytisine plus a nicotine EC) 12 weeks of cytisine (as above) and 12 weeks of a nicotine EC. Participants will also receive six months of text‐based smoking cessation support.
Outcomes	Baseline, 3, 6 and 12 months post‐quit date  Primary outcome: Proportion of participants with verified continuous smoking abstinence CO confirmed Self‐reported continuous smoking abstinence; self‐reported 7‐day point prevalence smoking abstinence; change from baseline in the number of cigarettes smoked per day; health‐related quality of life; cystine compliance; use of allocated treatment by participants; frequency of EC use, number of pods used; treatment switching; dual use; AEs; number of text‐based behavioural support messages received by participants; marginal cost per quitter
Starting date	Study start date: May 6 2022. Estimated primary completion date: February 2024
Contact information	Natalie Walker, PhD 64‐9‐923‐9884, n.walker@auckland.ac.nz Chris Bullen, PhD MBChB 64‐9‐923‐4730, c.bullen@auckland.ac.nz
Notes	New to 2022 update