Cytisinicline Heads Toward FDA Decision as Long-Term Safety Data Backs First New Smoking Cessation Drug in Two Decades

Overview

A plant-derived alkaloid that has quietly helped smokers in Central and Eastern Europe for more than sixty years may soon reach American patients for the first time. Achieve Life Sciences is expecting an FDA decision by June 20, 2026 on its New Drug Application for cytisinicline — a treatment for nicotine dependence that, if approved, would be the first new pharmacotherapy for smoking cessation cleared in the United States since varenicline in 2006. On May 19, 2026, the company presented comprehensive long-term safety data at the American Thoracic Society 2026 Annual Meeting, reinforcing an evidence package built on two large Phase 3 trials and more than 2,000 clinical trial participants.

What We Know

The drug and its mechanism

Cytisinicline is a synthetic form of cytisine, a plant-based alkaloid derived from Cytisus laburnum, or Golden Rain acacia. It works as a partial agonist of the nicotinic acetylcholine receptors, specifically in the α4β2 subtype — the same receptor population targeted by varenicline. That partial agonism allows the drug to blunt nicotine withdrawal and craving without fully activating the reward circuitry that sustains dependence. Tabex, the cytisine-based product, has been licensed in parts of Eastern Europe since 1964, but until now no version of the molecule has cleared a Western regulatory review.

Phase 3 trial results

The NDA rests primarily on the ORCA-2 and ORCA-3 trials. ORCA-3 — a double-blind, placebo-controlled, 3-group randomized clinical trial conducted at 20 sites in 15 US states and published in JAMA Internal Medicine on April 21, 2025 — enrolled 792 participants and was led by Nancy A. Rigotti, MD of Harvard Medical School. Participants averaged 52 years of age, smoked roughly 20 cigarettes a day, and had a 36-year median smoking history with 4 prior quit attempts on average. All participants received behavioral support of up to 14 sessions.

The primary endpoint — biochemically verified continuous abstinence during the last four weeks of treatment — was met in both treatment arms. In the 12-week arm, 30.3% of cytisinicline participants achieved abstinence versus 9.4% of placebo participants (odds ratio 4.4; 95% CI 2.6–7.3; P<.001). In the 6-week arm, 14.8% versus 6.0% (OR 2.9; P<.001). Sustained abstinence through the 24-week follow-up period was 20.5% versus 4.2% for the 12-week arm (OR 5.8; P<.001) and 6.8% versus 1.1% for the 6-week arm (OR 6.3; P<.001). As the authors summarized, “Cytisinicline produced a 3- to 4-fold higher odds of smoking cessation vs placebo at the end of treatment, and an approximately 6-fold higher odds of smoking cessation continuing through 24-week follow-up.”

OCRA-2, reported separately, enrolled 810 adult smokers and produced similar results: abstinence at end of 12-week treatment was 32.6% versus 7.0% for placebo (OR 6.3), and for the 6-week arm 25.3% versus 4.4% (OR 8.0).

Safety profile and long-term data

In ORCA-3, serious adverse events were reported in 3.1% of both the cytisinicline and placebo groups, and none were treatment-related. Drug discontinuation due to adverse events was 1.7% for cytisinicline versus 1.1% for placebo. The most commonly reported adverse events included insomnia (up to 11.9%), nausea (up to 9.5%), abnormal dreams (up to 9.1%), and headache (up to 8.5%).

The new data presented at ATS 2026 come from ORCA-OL, an open-label trial that enrolled 475 adults — 84.6% cigarette smokers, 12.8% e-cigarette users, and 2.5% dual users — and followed them through up to 52 weeks of continuous treatment at 3 mg three times daily. Median cumulative treatment duration was 361 days. No new safety signals were identified by the independent Data Safety Monitoring Committee. Of all treatment-emergent adverse events, 94.8% were mild or moderate in severity. Serious adverse events occurred in 6.5% of participants. Treatment discontinuation due to adverse events was 5.7%. Nausea, a concern sometimes raised for this class of drugs, was reported in only 2.5% of participants, consistent with the Phase 3 data. “The ORCA-OL dataset provides important long-term safety and tolerability information across a broad population of adults with nicotine dependence,” said Mark Rubinstein, MD, Chief Medical Officer of Achieve Life Sciences.

Regulatory trajectory

The FDA accepted Achieve Life Sciences’ NDA on September 3, 2025, setting a PDUFA targeted action date of June 20, 2026. The NDA is backed by over a decade of research. Safety data at submission included more than 400 participants with at least six months of cumulative exposure and more than 200 with at least one year of exposure — before the ORCA-OL dataset added further long-term evidence.

In parallel, the company received one of only nine National Priority Vouchers in the FDA’s inaugural voucher program in October 2025, for a separate indication: vaping cessation. The FDA has also granted cytisinicline Breakthrough Therapy designation for that indication, and a Phase 2 ORCA-V1 trial showed participants on cytisinicline were 2.6x more likely to quit vaping versus placebo, with results published in JAMA Internal Medicine. A Phase 3 vaping cessation trial, ORCA-V2, is planned.

What We Don’t Know

The FDA may approve, reject, or issue a complete response letter requesting additional information — the June 20 date is a target, not a guarantee. While ORCA-2 and ORCA-3 establish efficacy versus placebo, no head-to-head trial of cytisinicline against varenicline has been conducted in the US regulatory program, leaving open the question of relative efficacy against the current standard of care. Longer-term real-world quit rates often diverge from controlled trial results, and it remains unclear how labeling, prescribing behavior, and insurance coverage will shape uptake if approval is granted. Achieve Life Sciences has described its commercial readiness target as the second half of 2026, but pricing and access terms have not been disclosed.

Analysis

The public health stakes are significant. According to the CDC, 67.7% of US adults who smoke want to quit, but fewer than one in ten succeed in any given year. Approximately 29 million Americans currently smoke combustible cigarettes, and roughly 15 million attempt to quit annually. Yet fewer than 4 in 10 adults who smoke cigarettes used proven treatments — counseling or medication approved by the FDA — when attempting to quit.

The pharmacotherapy toolkit has been static for nearly twenty years. Nicotine replacement therapies, bupropion, and varenicline remain the approved options. Achieve Life Sciences CEO Rick Stewart has stated that “Smoking is the leading cause of preventable death and disease, claiming the lives of nearly half a million Americans each year” and that cytisinicline is intended to address an indication that has seen no new therapy in roughly two decades.

Cytisinicline’s mechanism — selective partial agonism at the α4β2 nicotinic acetylcholine receptor — closely resembles varenicline’s, but its plant-derived origin and distinct pharmacokinetic profile have been cited as differentiating characteristics. CMO Dr. Cindy Jacobs noted that “Cytisinicline is very selective in targeting only nicotine receptors with limited off-target binding.” Lead investigator Dr. Nancy Rigotti observed that “Cytisinicline could help many smokers quit and reduce smoking-related health risks.”

The timing of the ATS safety data presentation — one month before the PDUFA date — appears deliberate, reinforcing the drug’s tolerability profile at a moment when FDA reviewers are completing their assessment. Whether cytisinicline adds meaningfully to quit rates at a population level, displaces existing treatments, or opens a new market among the estimated 17 million adult e-cigarette users who have no approved cessation option will depend on decisions that follow well after June 20.