Effectiveness, safety and cost-effectiveness of vaporized nicotine products versus nicotine replacement therapy for tobacco smoking cessation in a low-socioeconomic status Australian population: a study protocol for a randomized controlled trial

Background: In Australia, tobacco smoking rates have declined but inequalities remain with significantly higher smoking prevalence among low-socioeconomic populations. Clinical trial data suggest vaporized nicotine products (VNPs) aid smoking cessation. Most VNP trials have used refillable tank systems, but newer generation (pod) devices now comprise the largest market share yet have limited clinical trial evidence on safety and effectiveness. This study evaluates the effectiveness, safety and cost-effectiveness of VNPs (pod and tank device) compared with nicotine replacement therapy ([NRT]-gum or lozenge) for smoking cessation. Methods: This is a two-arm, open-label, superiority, parallel group, randomized controlled trial (RCT) with allocation concealment and blinded outcome assessment. The RCT is conducted at the National Drug and Alcohol Research Centre at the University of New South Wales, Sydney, Australia. Participants are people who smoke daily, are interested in quitting and receive a government pension or allowance (N = 1058). Participants will be randomized (1:1 ratio) to receive 8 weeks of free: VNPs, with pod (40 mg/mL nicotine salt) and tank device (18 mg/mL freebase nicotine) in mixed flavours; or NRT (gum or lozenge; 4 mg). All participants will receive daily text message behavioural support for 5 weeks. Assessments will be undertaken by telephone at baseline, with three follow-up calls (two check-in calls within the first month and final follow-up at 7 months post randomization) to ascertain smoking status, treatment adherence and adverse events. The primary outcome is 6-month continuous abstinence verified by carbon monoxide breath test of <= 5 ppm at 7-month follow-up. Safety and cost-effectiveness of VNPs versus NRT will also be evaluated. Discussion: Further data are required to strengthen certainty of evidence for VNPs aiding smoking cessation, particularly for newer generation pod devices. To our knowledge, this trial is the first to offer choice of VNPs and no comparative effectiveness trial data exists for new pod devices. If effective, the findings can inform wider implementation of VNPs to aid smoking cessation in a priority group.