Drug Update · Pulmonology

Cytisinicline: ORCA-2 Showed 32.6% vs 7.0% Continuous Abstinence (weeks 9–12)

August 09, 2026

Trial name

ORCA-2

12-week continuous abstinence (weeks 9–12)

32.6% vs 7.0% (cytisinicline vs placebo)

6-week continuous abstinence (weeks 3–6)

25.3% vs 4.4% (cytisinicline vs placebo)

Participants randomized

810

Clinical Perspective

Pulmonologists and primary care clinicians treating adults who smoke cigarettes daily and want to quit should be aware that cytisinicline schedules with behavioral support produced higher biochemically verified continuous abstinence rates than placebo in the ORCA-2 randomized trial ^[1]. The trial data support that both a 6-week and a 12-week pharmacokinetically based dosing schedule with behavioral support demonstrated smoking cessation efficacy and tolerability in the study population ^[1]. How cytisinicline compares in head-to-head trials with existing pharmacotherapies for tobacco dependence remains an open question?

Dr. Nikhil Chatterjee · Pulmonology

Cytisinicline (cytisine) produced higher biochemically verified continuous smoking abstinence rates than placebo in the randomized ORCA-2 trial. For the 12-week course, continuous abstinence during weeks 9 to 12 was 32.6% with cytisinicline versus 7.0% with placebo; for the 6-week course, continuous abstinence during weeks 3 to 6 was 25.3% versus 4.4% with placebo ^[1].

Clinical Context

Cytisinicline (also referred to as cytisine) is a plant-based alkaloid that binds selectively to α4β2 nicotinic acetylcholine receptors, a receptor class that mediates nicotine dependence, and its pharmacology has been compared to varenicline in mechanisms described by the trial authors ^[1]. The ORCA-2 investigators noted that cytisinicline is used in some European countries but was not licensed in the US at the time of the publication ^[1]. The trial publication lists Achieve Life Sciences among affiliations for several authors and describes a pharmacokinetically based dosing regimen evaluated in two treatment durations with behavioral support ^[1]. An unapproved homeopathic cytisine strip product is listed on DailyMed as an unapproved homeopathic marketing category, with TBX-FREE cytisine strip labeled as cytisine 8 mg per strip and marketed historically by Dalian Jixin Electronic Information Co., Ltd. Clinicians should consult current prescribing information for full dosing guidance. on DailyMed ^[2].

Key Findings

The ORCA-2 trial showed cytisinicline achieved continuous abstinence rates of 32.6% versus 7.0% with placebo during weeks 9 to 12 for the 12-week regimen (12-week cytisinicline vs placebo) ^[1].
The ORCA-2 trial showed cytisinicline achieved continuous abstinence rates of 25.3% versus 4.4% with placebo during weeks 3 to 6 for the 6-week regimen (6-week cytisinicline vs placebo) ^[1].
Secondary, longer-term abstinence outcomes included 21.1% versus 4.8% during weeks 9 to 24 for the 12-week course (cytisinicline vs placebo) and 8.9% versus 2.6% during weeks 3 to 24 for the 6-week course (cytisinicline vs placebo); odds ratios and 95% CIs are reported in the trial publication ^[1].

Safety & Tolerability

Nausea occurred in less than 10% of each group ^[1].
Abnormal dreams occurred in less than 10% of each group ^[1].
Insomnia occurred in less than 10% of each group ^[1].
Sixteen participants (2.9%) discontinued cytisinicline due to an adverse event ^[1].
No drug-related serious adverse events occurred in the trial ^[1].

Study Design

ORCA-2 was a 3-group, double-blind, placebo-controlled, randomized trial that compared two durations of cytisinicline treatment (6 weeks or 12 weeks) versus placebo, with follow-up to 24 weeks among 810 adults who smoked cigarettes daily and wanted to quit ^[1]. Randomization was 1:1:1 to cytisinicline 3 mg three times daily for 12 weeks (n = 270); cytisinicline 3 mg three times daily for 6 weeks then placebo three times daily for 6 weeks (n = 269); or placebo three times daily for 12 weeks (n = 271), and all participants received behavioral support ^[1]. Clinicians should consult current prescribing information for full dosing guidance. The primary outcome was biochemically verified continuous smoking abstinence for the last 4 weeks of cytisinicline treatment versus placebo, with secondary outcomes extending abstinence assessment to 24 weeks ^[1].

FAQ

Q1 What did the ORCA-2 trial show?

The ORCA-2 randomized, double-blind, placebo-controlled trial reported that cytisinicline administered in pharmacokinetically based schedules with behavioral support produced higher biochemically verified continuous smoking abstinence rates than placebo. For the 12-week course, continuous abstinence during weeks 9 to 12 was 32.6% with cytisinicline versus 7.0% with placebo. For the 6-week course, continuous abstinence during weeks 3 to 6 was 25.3% versus 4.4% with placebo. The publication also reports longer-term abstinence through 24 weeks for both schedules.

Q2 Who was enrolled in ORCA-2?

ORCA-2 enrolled 810 adults who smoked cigarettes daily and wanted to quit, and the study was conducted at 17 US sites from October 2020 to December 2021. Participants were randomized 1:1:1 to one of three arms: a 12-week cytisinicline regimen, a 6-week cytisinicline regimen followed by placebo, or 12 weeks of placebo; all participants received behavioral support. The trial population’s baseline characteristics and the number completing the trial are reported in the publication.

Q3 What were the side effects in ORCA-2?

In the trial, nausea, abnormal dreams, and insomnia each occurred in less than 10% of participants in each group. Sixteen participants (2.9%) discontinued cytisinicline because of an adverse event, and the investigators reported that no drug-related serious adverse events occurred during the study. The publication provides these safety data in the context of the trial’s overall tolerability findings.

Q4 What does ORCA-2 mean for clinical practice?

The ORCA-2 results indicate that cytisinicline schedules with behavioral support demonstrated greater biochemically verified continuous smoking abstinence than placebo in this randomized trial population. The trial publication notes that cytisinicline is used in some European countries but was not licensed in the United States at the time of publication, and clinicians should interpret these results in the context of regulatory status and available prescribing information. Further comparative data and regulatory guidance would inform placement of cytisinicline alongside existing pharmacotherapies for tobacco dependence.

Clinicians should consult current prescribing information for full dosing guidance.

Cytisinicline: ORCA-2 Showed 32.6% vs 7.0% Continuous Abstinence (weeks 9–12)

Direct Clinical Takeaway & Evidence Summary

Cytisinicline: ORCA-2 Showed 32.6% vs 7.0% Continuous Abstinence (weeks 9–12)

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

Study Design

FAQ

References

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