Trial Information

Phase 1 Study on Smoking Cessation Effect of Tea Filter

Cigarette smoking has been linked to many life threatening diseases including heart
diseases, cancer and chronic obstructive pulmonary disease. There are about 1.25 billion
smokers in the world. Five million people die every year because of smoking-related
diseases. This rate exceeds many other diseases combined. It is estimated that the global
cost for smoking-related diseases is about $200 billion each year, posing one of the biggest
public human health problems around the world. Many methods have been developed for smoking
cessation by scientists and doctors worldwide. However, due to the addictive nature of
nicotine, quitting smoking is extremely difficult. Despite all the efforts, currently
available smoking cessation methods produce only modest successful rates with relapse. In
addition, they are often not convenient and can lead to a wide variety of side effects.
Therefore, the need of new idea for developing new smoking cessation techniques with better
efficacy and fewer side effects is urgent.

Epidemiological evidences have shown that tea is adversely associated with cancer,
hyperglycemia and other diseases. In addition, we have shown that tea components protect
cells from cigarette smoke-induced toxicity. Recently, we have developed a new cigarette
filter containing tea. While testing the filter for detoxification effects, we found that
several subjects who were smokers decreased their cigarette consumption and subsequently
abstained from cigarette smoking after using the tea filter for a period of time. Animal
experiments revealed that a derivative tea component prevented nicotine addiction similar to
nicotine acetylcholine receptor (nAChR) inhibitor. It significantly inhibited the
nicotine-induced expression of alpha4,alpha7 and β2 subunits of nAChR and tyrosine
hydroxylase and release of dopamine. This finding encouraged us to recruit more volunteers
to test the smoking cessation effect of the tea filter.

One hundred healthy male cigarette smokers, aged 18 to 30 years, were screened and 30 of
them were excluded based on the exclusion/inclusion criteria. 70 volunteers were
double-blinded, placebo-controlled and randomized into 2 groups (smoking with tea filters or
regular filters). Smoking history, including the nicotine dependence, was assessed at the
screening visit. Exclusion criteria included treatment with an investigational drug within
the previous month; major depression within the prior year; panic disorder, psychosis, or
bipolar disorder; use of nicotine replacement therapy or other drugs within the previous 3
months; cardiovascular disease; clinically significant medical disease; drug or alcohol
abuse or dependence within the past year; and use of tobacco products other than cigarette
smoking within the previous month. Subjects received brief smoking cessation counseling (up
to 10 minutes) at the baseline visit and at each visit afterwards. Self-reported smoking
status since the last visit and exhaled carbon monoxide measurement were assessed at each
weekly visit. Vital signs, weight, and adverse event information were collected at each
visit. A physical examination was performed prior to randomization and at the final visit.
Urine and blood were collected at screening, baseline, and at weeks 1, 2, 3, and 4 for
biochemical analysis.

The average number of cigarettes consumed daily by one volunteer smoker before the clinic
trial was calculated as control. The average number of cigarettes consumed daily by one
volunteer after the clinic trial was calculated and the numbers were then used to calculate
the averages number of cigarettes consumed daily by one smoker in a week and compared with
control. Continuous abstinence was defined as self-report of no cigarette use during the
specified time period confirmed by an exhaled carbon monoxide measurement of 10 ppm or
lower. To be considered abstinent from smoking during the treatment period, subjects also
had to report that they did not use any other nicotine-containing products. During the
follow-up period, use of nicotine replacement therapy did not disqualify subjects from being
considered abstinent. Subjects who withdrew or were lost to follow-up were assumed to be
smokers for the remainder of the study. The exhaled carbon monoxide was detected by a
carbon monoxidemeter (1209-1 CO, DWYER, USA). Nicotine and cotinine in urine was detected
using HPLC (HITACH, Japan) as reported in the literature.

30 volunteers in control group and 22 volunteer male cigarette smokers who consumed on
average approximately cigarettes per day, were randomly divided into 2 groups (double-blind,
placebo-controlled); smoking with tea filters or with regular filters. After using the tea
filter for 1 month, the average daily cigarette consumption decreased about 43% in the tea
filter group. In contrast, no change in average daily cigarette consumption was detected in
the control group using regular filters. The trial was discontinued for the control group
and the tea filter group was followed for another month. After using the tea filter for 2
months.

We then recruited 59 volunteers with longer smoking history and stronger desire for quitting
smoking for smoking cessation test using the tea filter. The subjects were followed for 5
month following the same protocol as described earlier.