European quit-smoking drug proven safe, effective in U.S. study

European cystine product (Medpage Today photo)

By Melissa Patrick

Kentucky Health News

Cytisinicline, a drug to help people stop smoking, was found to be safe and effective when used at a higher concentration than is traditionally used in Europe, where it is currently being used. It is not yet available in the United States. 

“Cigarette smoking remains the leading preventable cause of death worldwide, yet no new smoking-cessation medication has been approved by the U.S. Food and Drug Administration for nearly two decades,” Dr. Nancy Rigotti,  director of Massachusetts General Hospital's Tobacco Research and Treatment Center, and lead author of the study, said in a press release. “There is an urgent need for new medications to treat tobacco smoking because existing products don’t help all smokers to quit and can have unacceptable side effects. If approved by regulators, cytisinicline could be a valuable new option to treat tobacco dependence.”

Cytisinicline, which is historically known as cytisine, is a naturally derived, plant-based medication that has been developed as a treatment for nicotine dependence and smoking cessation. It is not licensed in the U.S., but is used in some European countries for smoking cessation. Some researchers have questioned whether the recommended dose and treatment duration are appropriate. 

The study, published in the Journal of the American Medical Association, found that both a six-week and a 12-week treatment of cytisinicline in 810 adults who smoke cigarettes daily and wanted to quit produced "significantly higher continuous smoking-abstinence rates" compared with a placebo during the last four weeks of treatment and from the end of treatment to 24 weeks. 

"Participants in the cytisinicline groups had six- to eight-fold higher odds of continuous smoking abstinence at the end of treatment than participants receiving placebo plus behavioral support," says the study report. 

The study involved a three-group, double-blind, placebo-controlled, randomized trial that compared a six-week and a 12-week duration of either cytisinicline treatment or a placebo, with follow-up through 24 weeks. It was conducted at 17 U.S. sites from October 2020 to December 2021. 

It found that in the six-week course of treatment, in weeks 3-6, continuous abstinence rates with cytisinicline were 25.3% and 4.4%. In the 12-week trial, the rates were 32.6% for cytisinicline and 7% for placebo in weeks 9-12.

Participants taking cytisinicline also experienced a rapid and sustained decline in cravings and smoking urges during the first six weeks of treatment, the researchers said.

The study also found a statistically significant increase in continuous abstinence through six months for both treatment durations.

The manufacturer's recommendation for the drug is for a 1.5-milligram tablet to be taken initially six times a day, and then gradually reduced over a 25-day course of treatment. However, the researchers found that 3 mg of cytisinicline three times a day produced the highest continuous abstinence.

The researchers reported "no adverse events" from taking the drug, with less than 10% of the participants experiencing nausea, abnormal dreams and insomnia.

The researchers concluded, "Both six- and 12-week cytisinicline schedules, with behavioral support, demonstrated smoking-cessation efficacy and excellent tolerability, offering a new nicotine-dependence treatment option." They also noted that no smoking-cessation drug has received FDA approval since 2006. 

“Cytisinicline demonstrated impressive results as a smoking-cessation medication in a rigorous clinical trial that used a new, scientifically based dosing regimen as well as a longer duration of treatment than traditionally done,” said Rigotti. “This agent has the potential to help countless numbers of people quit smoking and, in the process, reduce the enormous toll of premature deaths and disability due to cigarette smoking in the U.S. and worldwide.”

In 2015, nearly 70% of adult smokers said they want to quit. In 2018, about 55% said they had made an attempt to quit in the previous year, but only about 8% were successful in quitting for six to 12 months, according to the latest data available from the Centers for Disease Control and Prevention.

In 2020, the latest year for which statistics are available, 21.4% of Kentucky adults were smokers. 

Many health-insurance plans, including Medicaid, cover FDA-approved smoking-cessation medicines with no copayments. Kentucky offers a free quit line at 1-800-QUIT-NOW that provides personalized coaching to help people quit smoking.