Achieve Life Sciences has shared final data from a phase 1/2 trial of its smoking cessation candidate cytisinicline. The data show the smoking reductions disclosed one year ago occurred within two days of treatment, sending the nanocap’s stock up as much as 90% in premarket trading.
Cytisinicline is an alkaloid isolated from the seeds of a flowering plant native to Europe. The drug is a partial nicotinic acetylcholine agonist that is approved for use in smoking cessation in parts of Central and Eastern Europe. Achieve picked up the rights to commercialize the drug in the U.S. and other key markets in 2015 from Bulgaria’s Sopharma and started a phase 1/2 clinical trial two years later.
The data presented this week come from that open-label phase 1/2 trial. After struggling to enroll people aged 65 and older into the trial, Achieve closed the study with 26 participants, two of whom were in the senior demographic, who were randomized to receive one of two doses of its drug.
At day 26, 46% of the subjects had stopped smoking. The cessation rate was slightly higher in the 3.0-mg arm than the 1.5-mg cohort, mirroring the trend seen across other endpoints. Four-fifths of participants reduced their smoking compared to baseline. The rate rose to 86% among the 13 people in the higher-dose arm.
The data are in line with, but are not identical to, the results Achieve shared one year ago on the 24 participants aged under 65. At that time, Achieve said the overall cessation rate was 58%. The rates for the 1.5-mg and 3.0-mg cohorts were 50% and 57%, respectively.
Achieve’s presentation at the Society for Research on Nicotine & Tobacco Annual Meeting featured some information absent from the preliminary readout, including an analysis of the speed of onset of action. At baseline, the subjects were smoking 17 cigarettes a day on average. That figure fell into single figures after one day of treatment and pretty much bottomed out lower still after two days.
The data suggest cytisinicline may work faster than Pfizer’s Chantix, while also being free from the side effects that have dogged that drug. But the small numbers of subjects in the phase 1/2 trial and the lack of a control arm make it hard to draw solid conclusions.
Achieve is working to address the limitations of its dataset by testing various regimens of cytisinicline and placebo in a 254-subject phase 2b. Topline data are due around the middle of the year.