Effect of flavored on!® nicotine pouch products on smoking behaviors: A sequential, multiple assignment, randomized controlled trial.
PURPOSE: To evaluate whether flavored versus unflavored nicotine pouch (NP) access affects cigarette reduction and smoke exposure among adults who smoke daily, and whether delayed flavor introduction affects these outcomes. METHODS: Adults who smoked ≥ 5 cigarettes/day (CPD) with interest in replacing cigarettes with NPs were enrolled in a remote, six-week, sequential multiple assignment randomized trial (n = 402 randomized; n = 400 analyzed). Participants were randomized to immediate access to seven NP flavors (Flavor), unflavored-only access for six weeks (Original), or unflavored-only for three weeks followed by flavor access (Delayed Flavor). Primary outcomes were ≥ 50% reduction in weekly mean expired-air carbon monoxide (CO) from baseline and mean CO at Week 6. Secondary outcomes included ≥ 50% CPD reduction, mean CPD, CO-verified 7-day abstinence, and incident smoke-free days. RESULTS: At Week 6, Flavor and Original did not differ in ≥ 50% CO reduction (14.3% vs 14.2%; IRR=1.0, 95% CI=0.6-1.8) or mean CO (18.3 vs 16.5 ppm; β=1.9, 95% CI=-1.3-5.0). CPD decreased across groups by Week 6, with no differences between Flavor and Original in ≥ 50% CPD reduction (50.3% vs 51.6%; IRR=1.0, 95% CI=0.8-1.2) or CO-verified abstinence (9.3% vs 8.9%; IRR=1.0, 95% CI=0.5-2.2). Flavor increased smoke-free days early, with attenuation over time. Among Week 3 non-responders, delayed flavor access increased ≥ 50% CPD reduction at Week 6 (33.3% vs 18.6%; IRR=1.8, 95% CI=1.0-3.2). CONCLUSIONS: NP access supported cigarette reduction regardless of flavor availability, but flavors may accelerate smoke-free days and improve response among individuals who do not reduce cigarette consumption with unflavored products alone.