Evaluation of the effectiveness of cytisine for the treatment of smoking cessation: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Smoking is considered the main cause of preventable death world-wide. This study aimed to review the efficacy and safety of cytisine for smoking cessation. METHODS: This review included an exhaustive search of databases to identify randomized controlled trials (RCTs) in health centers of any level with smokers of any age or gender investigating the effects of cytisine at standard dosage versus placebo, varenicline or nicotine replacement therapy (NRT). RESULTS: We identified 12 RCTs. Eight RCTs compared cytisine with placebo at the standard dose covering 5922 patients, 2996 of whom took cytisine, delivering a risk ratio (RR) of 2.25 [95% confidence interval (CI) = 1.42-3.56; I2  = 88%; moderate-quality evidence]. The greater intensity of behavioral therapy was associated directly with the efficacy findings (moderate-quality evidence). The confirmed efficacy of cytisine was not evidenced in trials conducted in low- and middle-income countries. We estimate a number needed to treat (NNT) of 11. Two trials compared the efficacy of cytisine versus NRT, and the combination of both studies yields modest results in favor of cytisine. Three trials compared cytisine with varenicline, without a clear benefit for cytisine. Meta-analyses of all non-serious adverse events in the cytisine group versus placebo groups yielded a RR of 1.24 (95% CI = 1.11-1.39; participants = 5895; studies = 8; I2 = 0%; high-quality evidence). CONCLUSIONS: Cytisine increases the chances of successful smoking cessation by more than twofold compared with placebo and has a benign safety profile, with no evidence of serious safety concerns. Limited evidence suggests that cytisine may be more effective than nicotine replacement therapy, with modest cessation rates.

Cytisine: State of the art in pharmacological activities and pharmacokinetics.

Cytisine is a naturally occurring bioactive compound, an alkaloid mainly isolated from legume plants. In recent years, various biological activities of cytisine have been explored, showing certain effects in smoking cessation, reducing drinking behavior, anti-tumor, cardiovascular protection, blood sugar regulation, neuroprotection, osteoporosis prevention and treatment, etc. At the same time, cytisine has the advantages of high efficiency, safety, and low cost, has broad development prospects, and is a drug of great application value. However, a summary of cytisine's biological activities is currently lacking. Therefore, this paper summarizes the pharmacological action, mechanism, and pharmacokinetics of cytisine by referring to numerous databases, and analyzes the new and core targets of cytisine with the help of computer simulation technology, to provide reference for doctors.

Cytisine as a smoking cessation aid: Preliminary observations with a modified therapeutic scheme in real life.

INTRODUCTION: Cigarette smoke accounts for over 90,000 deaths each year in Italy. Tobacco dependence treatment guidelines suggest adopting an integrated pharmacological-behavioral model of intervention. Cytisine is a partial agonist of nicotinic receptors. Trials conducted to date have demonstrated its good efficacy in promoting smoking cessation. The cytisine scheme of treatment consists of 25 days of treatment. A 40-day regimen, with an escalating dose and an extended duration of the treatment, has been in use in many anti-smoking centers in Italy for several years, but to date there are no reports on the use of cytisine with this scheme. METHODS: A retrospective, real-life, observational study was conducted between January 2016 and September 2022. The 300 patients who had received at least one dose of study medication were selected. Continuous variables were compared by the Wilcoxon-Mann-Whitney test. Univariate and multivariate logistic regression models were implemented for self-reported seven-day point prevalence for abstinence at three, six and 12 months. RESULTS: The median age of the patients was 59 years, 57% were women. The median smoking exposure was 33.8 pack-years. Self-reported smoking abstinence at three, six and 12 months was 68.7%, 56.3% and 47.3% respectively. 84% completed the cytisine treatment, 31.3% reported adverse events and in 8.3% these led to dropping out of the treatment. CONCLUSION: Cytisine, administered with a novel therapeutic scheme in the real-life setting of a specialized anti-smoking center, significantly promotes smoking abstinence. However, more studies are needed to assess the tolerability and efficacy of this new regimen.

Cytisine Versus Varenicline for Smoking Cessation in a Primary Care Setting: A Randomized Non-inferiority Trial.

INTRODUCTION: A smoking-cessation program was implemented as a randomized non-inferiority trial in primary care practices in Croatia and Slovenia to investigate whether a standard 4-week treatment with cytisine was at least as effective and feasible as a standard 12-week treatment with varenicline in helping smokers quit. AIMS AND METHODS: Out of 982 surveyed smokers, 377 were recruited to the non-inferiority trial: 186 were randomly assigned to cytisine and 191 to varenicline treatment. The primary cessation outcome was 7-day abstinence after 24 weeks, while the primary feasibility outcome was defined by adherence to the treatment plan. We also compared the rates of adverse events between the two treatment groups. RESULTS: The cessation rate after 24 weeks was 32.46% (62/191) in the varenicline group and 23.12% (43/186) in the cytisine group (odds ratio [OR]: 95%, credible interval [CI]: 0.39 to 0.98). Of 191 participants assigned to varenicline treatment 59.16% (113) were adherent, while 70.43% (131 of 186) were adherent in the cytisine group (OR: 1.65, 95% CI: 1.07 to 2.56). Participants assigned to cytisine experienced fewer total (incidence rate ratio [IRR]: 0.59, 95% CI: 0.43 to 0.81) and fewer severe or more extreme adverse events (IRR: 0.72, 95% CI: 0.35 to 1.47). CONCLUSIONS: This randomized non-inferiority trial (n = 377) found the standard 4-week cytisine treatment to be less effective than the standard 12-week varenicline treatment for smoking cessation. However, adherence to the treatment plan, ie, feasibility, was higher, and the rate of adverse events was lower among participants assigned to cytisine treatment. IMPLICATIONS: The present study found the standard 12 weeks of varenicline treatment to be more effective than the standard 4 weeks of cytisine treatment for smoking cessation in a primary care setting in Croatia and Slovenia. Participants assigned to cytisine, however, had a higher adherence to the treatment plan and a lower rate of adverse events. Estimates from the present study may be especially suitable for generalizations to high-smoking prevalence populations in Europe. Given the much lower cost of cytisine treatment, its lower rate of adverse events, and higher feasibility (but its likely lower effectiveness with the standard dosage regimen), future analyses should assess the cost-effectiveness of the two treatments for health policy considerations.

Effect of Cytisine vs Varenicline on Smoking Cessation: A Randomized Clinical Trial.

Importance: Cytisine is more effective than placebo and nicotine replacement therapy for smoking cessation. However, cytisine has not been tested against the most effective smoking cessation medication, varenicline, which is associated with adverse events known to lead to discontinuation of therapy. Objective: To examine whether standard cytisine treatment (25 days) was at least as effective as standard varenicline treatment (84 days) for smoking cessation. Design, Setting, and Participants: This noninferiority, open-label randomized clinical trial with allocation concealment and blinded outcome assessment was undertaken in Australia from November 2017 through May 2019; follow-up was completed in January 2020. A total of 1452 Australian adult daily smokers willing to make a quit attempt were included. Data collection was conducted primarily by computer-assisted telephone interview, but there was an in-person visit to validate the primary outcome. Interventions: Treatments were provided in accordance with the manufacturers' recommended dosage: cytisine (n = 725), 1.5-mg capsules taken 6 times daily initially then gradually reduced over the 25-day course; varenicline (n = 727), 0.5-mg tablets titrated to 1 mg twice daily for 84 days (12 weeks). All participants were offered referral to standard telephone behavioral support. Main Outcomes and Measures: The primary outcome was 6-month continuous abstinence verified using a carbon monoxide breath test at 7-month follow-up. The noninferiority margin was set at 5% and the 1-sided significance threshold was set at .025. Results: Among 1452 participants who were randomized (mean [SD] age, 42.9 [12.7] years; 742 [51.1%] women), 1108 (76.3%) completed the trial. Verified 6-month continuous abstinence rates were 11.7% for the cytisine group and 13.3% for the varenicline group (risk difference, -1.62% [1-sided 97.5% CI, -5.02% to ∞]; P = .03 for noninferiority). Self-reported adverse events occurred less frequently in the cytisine group (997 events among 482 participants) compared with the varenicline group (1206 events among 510 participants) and the incident rate ratio was 0.88 (95% CI, 0.81 to 0.95; P = .002). Conclusions and Relevance: Among daily smokers willing to quit, cytisine treatment for 25 days, compared with varenicline treatment for 84 days, failed to demonstrate noninferiority regarding smoking cessation. Trial Registration: anzctr.org.au Identifier: ACTRN12616001654448.

Cytisine for smoking cessation in patients with tuberculosis: a multicentre, randomised, double-blind, placebo-controlled phase 3 trial.

BACKGROUND: Smoking cessation is important in patients with tuberculosis because it can reduce the high rates of treatment failure and mortality. We aimed to assess the effectiveness and safety of cystine as a smoking cessation aid in patients with tuberculosis in Bangladesh and Pakistan. METHODS: We did a randomised, double-blind, placebo-controlled, trial at 32 health centres in Bangladesh and Pakistan. Eligible patients were adults (aged >18 years in Bangladesh; aged >15 years in Pakistan) with pulmonary tuberculosis diagnosed in the previous 4 weeks, who smoked tobacco on a daily basis and were willing to stop smoking. Patients were randomly assigned (1:1) to receive behavioural support plus either oral cytisine (9 mg on day 0, which was gradually reduced to 1·5 mg by day 25) or placebo for 25 days. Randomisation was done using pregenerated block randomisation lists, stratified by trial sites. Investigators, clinicians, and patients were masked to treatment allocation. The primary outcome was continuous abstinence at 6 months, defined as self-report (of not having used more than five cigarettes, bidis, a water pipe, or smokeless tobacco products since the quit date), confirmed biochemically by a breath carbon monoxide reading of less than 10 parts per million. Primary and safety analysis were done in the intention-to-treat population. This trial is registered with the International Standard Randomised Clinical Trial Registry, ISRCTN43811467, and enrolment is complete. FINDINGS: Between June 6, 2017, and April 30, 2018, 2472 patients (1527 patients from Bangladesh; 945 patients from Pakistan) were enrolled and randomly assigned to receive cytisine (n=1239) or placebo (n=1233). At 6 months, 401 (32·4%) participants in the cytisine group and 366 (29·7%) participants in the placebo group had achieved continuous abstinence (risk difference 2·68%, 95% CI -0·96 to 6·33; relative risk 1·09, 95% CI 0·97 to 1·23, p=0·114). 53 (4·3%) of 1239 participants in the cytisine group and 46 (3·7%) of 1233 participants in the placebo group reported serious adverse events (94 events in the cytisine group and 90 events in the placebo group), which included 91 deaths (49 in the cytisine group and 42 in the placebo group). None of the adverse events were attributed to the study medication. INTERPRETATION: Our findings do not support the addition of cytisine to brief behavioural support for the treatment of tobacco dependence in patients with tuberculosis. FUNDING: European Union Horizon 2020 and Health Data Research UK. TRANSLATIONS: For the Bengali and Urdu translations of the abstract see Supplementary Materials section.

Pharmacological Approach to Smoking Cessation: An Updated Review for Daily Clinical Practice.

Tobacco use is one of the major public health concerns and it is the most preventable cause of morbidity and mortality worldwide. Smoking cessation reduces subsequent cardiovascular events and mortality. Smoking is a real chronic disorder characterized by the development of an addiction status mainly due to nicotine. This condition makes the smokers generally unable to quit smoking without help. Different strategies are available to treat smoking dependence that include both non-pharmacological (behavioral counselling) and pharmacological therapies. Currently, it is well accepted that smoking cessation drugs are effective and safe in real-world settings. Nicotine replacement therapy (NRT), varenicline, bupropion and cytisine are the main pharmacological strategies available for smoking cessation. Their efficacy and safety have been proved even in patients with chronic cardiovascular disease. Each of these drugs has peculiar characteristics and the clinician should customize the smoking cessation strategy based on currently available scientific evidence and patient's preference, paying particular attention to those patients having specific cardiovascular and psychiatric comorbidities. The present document aims to summarize the current viable pharmacological strategies for smoking cessation, also discussing the controversial issue regarding the use of alternative tobacco products, in order to provide useful practical indications to all physicians, mainly to those involved in cardiovascular prevention.

The inhibitor of apoptosis proteins antagonist Debio 1143 promotes the PD-1 blockade-mediated HIV load reduction in blood and tissues of humanized mice.

The immune checkpoint programmed cell death protein 1 (PD-1) plays a major role in T cell exhaustion in cancer and chronic HIV infection. The inhibitor of apoptosis protein antagonist Debio 1143 (D1143) enhances tumor cell death and synergizes with anti-PD-1 agents to promote tumor immunity and displayed HIV latency reversal activity in vitro. We asked in this study whether D1143 would stimulate the potency of an anti-human PD-1 monoclonal antibody (mAb) to reduce HIV loads in humanized mice. Anti-PD-1 mAb treatment decreased PD-1+ CD8+ cell population by 32.3% after interruption of four weeks treatment, and D1143 co-treatment further reduced it from 32.3 to 73%. Anti-PD-1 mAb administration reduced HIV load in blood by 94%, and addition of D1143 further enhanced this reduction from 94 to 97%. D1143 also more profoundly promoted with the anti-PD-1-mediated reduction of HIV loads in all tissues analyzed including spleen (71 to 96.4%), lymph nodes (64.3 to 80%), liver (64.2 to 94.4), lung (64.3 to 80.1%) and thymic organoid (78.2 to 98.2%), achieving a >5 log reduction of HIV loads in CD4+ cells isolated from tissues 2 weeks after drug treatment interruption. Ex vivo anti-CD3/CD28 stimulation increased the ability to activate exhausted CD8+ T cells in infected mice having received in vivo anti-PD-1 treatment by 7.9-fold (5 to 39.6%), and an additional increase by 1.7-fold upon D1143 co-treatment (39.6 to 67.3%). These findings demonstrate for the first time that an inhibitor of apoptosis protein antagonist enhances in a statistically manner the effects of an immune check point inhibitor on antiviral immunity and on HIV load reduction in tissues of humanized mice, suggesting that the combination of two distinct classes of immunomodulatory agents constitutes a promising anti-HIV immunotherapeutic approach.

Novel cytisine derivatives exert anti-liver fibrosis effect via PI3K/Akt/Smad pathway.

A series of new cytisine derivatives with a unique endocyclic scaffold were synthesized and evaluated for their inhibitory effect on collagen α1 (I) (COL1A1) promotor in human LX2 cells, taking cytisine as the lead. Structure-activity relationship (SAR) revealed that introducing a 12N-benzyl substitution might significantly enhance the activity. Compound 5f exhibited a promising inhibitory potency against COL1A1 with an IC50 value of 12.8 µM in human LX2 cells, and an inspiring inhibition activity against COL1A1 on both mRNA and protein levels. It also effectively inhibited the expression of α smooth muscle actin (α-SMA), connective tissue growth factor (CTGA), matrix metalloprotein 2 (MMP-2), and transforming growth factor ß1 (TGFß1), indicating an extensive inhibitory effect against fibrogenetic proteins. In addition, compound 5f displayed reasonable PK and safety profiles. The primary mechanism study indicated that it might repress the hepatic fibrogenesis via PI3K/Akt/Smad signaling pathway. The results provided powerful information for further structure optimization, and compound 5f was selected as a novel anti-liver fibrosis agent for further investigation.

Cytisine for nicotine addiction treatment: a review of pharmacology, therapeutics and an update of clinical trial evidence for smoking cessation.

AIMS: To review cytisine's history of use, pre-clinical evidence, clinical pharmacokinetics, efficacy, adverse reactions (ARs) and safety for smoking cessation. METHODS: A synoptic review of the use of cytisine as a smoking cessation medication, mechanism of action, pharmacokinetics and safety. Relevant literature on data included in these sections were identified through a search of 11 databases with additional literature obtained from reports and monographs. Three databases (PubMed, EMBASE and www.elibrary.ru) were systematically searched for studies published from 2012 to August 2018 in any language to provide an updated meta-analysis of cytisine's efficacy and ARs for smoking cessation compared with placebo. We pooled the relative risks (RR) of abstinence in the efficacy analysis and RR of ARs, either reported by the authors or calculated from the reports. RESULTS: Cytisine has been in use since 1964 and is currently marketed in 18 countries. Systemic bioavailability from oral ingestion is high and clearance is primarily renal, with minimal or no metabolism. Brain uptake in animal models is moderate. The plasma half-life averages 4.8 hours. Eight studies were included for meta-analysis of efficacy. With heterogeneous results, the overall RR versus placebo of successful continuous abstinence at the longest follow-up was 1.74 [95% confidence interval (CI) = 1.38-2.19]. Nausea, vomiting, dyspepsia, upper abdominal pain and dry mouth that were mild or moderate were the most common ARs, with RR versus placebo 1.10 (95% CI = 0.95-1.28). The cost of cytisine in eastern and central Europe is several-fold less than that of other smoking cessation medications. CONCLUSIONS: Cytisine is a low-cost medication found to increase the likelihood of smoking cessation. The most frequently reported ARs of cytisine involve gastrointestinal symptoms that are mostly reported as either mild or moderate in severity.

Cytisine versus varenicline for smoking cessation for Maori (the indigenous people of New Zealand) and their extended family: protocol for a randomized non-inferiority trial.

BACKGROUND AND AIMS: Cytisine, a nicotinic acetylcholine receptor partial agonist (like varenicline) found in some plants, is a low-cost, effective smoking cessation medication that may appeal to Maori [the indigenous people of New Zealand (NZ)]. The RAUORA trial aims to determine the effectiveness, safety and cost-effectiveness of cytisine (Tabex® ) versus varenicline (Champix® ) for smoking cessation in Maori and the whanau (extended family) of Maori. DESIGN: Pragmatic, community-based, open-label randomized non-inferiority trial. SETTING: Lakes District Health Board region, NZ. PARTICIPANTS: Daily smokers (n = 2140) who self-identify as Maori or whanau of Maori, and are: aged ≥ 18 years, motivated to quit smoking in the next 2 weeks, eligible for subsidized varenicline, able to provide verbal consent and have daily access to a mobile phone/internet. Recruitment uses multi-media advertising. INTERVENTION AND COMPARATOR: Participants are randomized (1 : 1 ratio) to receive a prescription for 12 weeks of cytisine tablets [following the manufacturer's dosing regimen for 25 days, then one 1.5-mg tablet every 6 hours (two per day) until 12 weeks] or varenicline tablets (following the manufacturer's dosing regimen). Both groups receive brief stop-smoking advice from the prescribing doctor and withdrawal-orientated behavioural support via community-based stop-smoking counselling services (frequency, duration and mode of delivery tailored for participants) or a research assistant (six weekly 10-15-minute calls). Participants are advised to reduce their smoking over the first 4 days of treatment, with day 5 as their designated quit-date. MEASUREMENTS: The primary outcome is carbon monoxide-verified continuous abstinence at 6 months post-quit date. Secondary outcomes at 1, 3, 6 and 12 months post-quit date include: self-reported continuous abstinence, 7-day point prevalence abstinence, cigarettes per day, time to (re)lapse, adverse events, treatment adherence/compliance, treatment acceptability, nicotine withdrawal/urge to smoke and health-care utilization/health-related quality of life. COMMENTS: This trial compares cytisine and varenicline when used by the indigenous people of NZ and their extended family for smoking cessation.

SMAC Mimetic Debio 1143 and Ablative Radiation Therapy Synergize to Enhance Antitumor Immunity against Lung Cancer.

PURPOSE: Adaptive antitumor immunity following ablative radiotherapy (ART) is attenuated by host myeloid-derived suppressor cell (MDSC), tumor-associated macrophage (TAM), and regulatory T-cell (Treg) infiltrates. We hypothesized treatment with ART and a secondary mitochondrial-derived activators of caspase (SMAC) mimetic could reverse the immunosuppressive lung cancer microenvironment to favor adaptive immunity. EXPERIMENTAL DESIGN: To evaluate for synergy between ART and the SMAC mimetic Debio 1143 and the dependence upon CD8+ T cells and TNFα, we used LLC-OVA syngeneic mouse model of lung cancer and treated them with Debio 1143 and/or ART (30 Gy) with or without anti-CD8, anti-TNFα, or anti-IFNγ antibodies. Tumor-infiltrating OVA-specific CD8+ T cells, Tc1 effector cells, MDSCs, TAMs, and Tregs, were quantified by flow cytometry. Tc1-promoting cytokines TNFα, IFNγ, and IL1ß and the immunosuppressive IL10 and Arg-1 within LLC-OVA tumor tissue or mouse serum were measured by RT-PCR and ELISA. RESULTS: ART delayed tumor growth, and the addition of Debio 1143 greatly enhanced its efficacy, which included several complete responses. These complete responders rejected an LLC-OVA tumor rechallenge. ART and Debio 1143 synergistically induced a tumor-specific, Tc1 cellular and cytokine response while eliminating immunosuppressive cells and cytokines from the tumor microenvironment. Depletion of CD8+ cells, TNFα, and IFNγ with blocking antibody abrogated synergy between ART and Debio 1143 and partially restored tumor-infiltrating MDSCs. CONCLUSIONS: Debio 1143 augments the tumor-specific adaptive immunity induced by ART, while reversing host immunosuppressive cell infiltrates in the tumor microenvironment in a TNFα, IFNγ, and CD8+ T-cell-dependent manner. This provides a novel strategy to enhance the immunogenicity of ART.

The effectiveness, safety and cost-effectiveness of cytisine versus varenicline for smoking cessation in an Australian population: a study protocol for a randomized controlled non-inferiority trial.

BACKGROUND AND AIMS: Smoking cessation medications are effective, but often underutilized because of costs and side effects. Cytisine is a plant-based smoking cessation medication with more than 50 years of use in central and eastern Europe. While cytisine has been found to be well-tolerated and more effective than nicotine replacement therapy, direct comparisons with varenicline have not been conducted. This study evaluates the effectiveness, safety and cost-effectiveness of cytisine compared with varenicline. DESIGN: Two-arm, parallel group, randomized, non-inferiority trial, with allocation concealment and blinded outcome assessment. SETTING: Australian population-based study. PARTICIPANTS: Adult daily smokers (n = 1266) interested in quitting will be recruited through advertisements and Quitline telephone-based cessation support services. INTERVENTION AND COMPARATOR: Eligible participants will be randomized (1 : 1 ratio) to receive either cytisine capsules (25-day supply) or varenicline tablets (12-week supply), prescribed in accordance with the manufacturer's recommended dosing regimen. The medication will be mailed to each participant's nominated residential address. All participants will also be offered standard Quitline behavioural support (up to six 10-12-minute sessions). MEASUREMENTS: Assessments will be undertaken by telephone at baseline, 4 and 7 months post-randomization. Participants will also be contacted twice (2 and 4 weeks post-randomization) to ascertain adverse events, treatment adherence and smoking status. The primary outcome will be self-reported 6-month continuous abstinence from smoking, verified by carbon monoxide at 7-month follow-up. We will also evaluate the relative safety and cost-effectiveness of cytisine compared with varenicline. Secondary outcomes will include self-reported continuous and 7-day point prevalence abstinence and cigarette consumption at each follow-up interview. COMMENTS: If cytisine is as effective as varenicline, its lower cost and natural plant-based composition may make it an acceptable and affordable smoking cessation medication that could save millions of lives world-wide.

Neuroprotection of Cytisine Against Cerebral Ischemia-Reperfusion Injury in Mice by Regulating NR2B-ERK/CREB Signal Pathway.

The aim of the study was to elucidate the therapeutic effects of Cytisine (CYT) on cerebral ischemia-reperfusion injury in mice. Male ICR mice were pretreated with reagents (drug), and then subjected to 2 h focal cerebral ischemia and 24 h reperfusion. Morphologically, the histopathological impairment were estimated by the TTC, HE and TUNEL staining. The expression of GluN2B-containing NMDA receptor, phosphorylation of extracellular regulated protein kinases, total ERK, phosphorylation of cAMP-response element binding protein and total CREB were determined by immunofluorescence and Western blot assay, respectively. The mRNA expression of NR2B, ERK and CREB were quantified by the real-time RT-PCR. CYT significantly diminished the infarct size and neuronal apoptosis. Additionally, it ameliorated histopathological lesion dramatically. CYT promoted the phosphorylation of ERK, CREB and their mRNA expression. In contrast, the expression of NR2B was suppressed in concomitant with the down-regulation of genes. The overall results thus far suggest that CYT confers the neuroprotection against cerebral I/R injury by regulating the NR2B-ERK/CREB signal pathway.

The IAP Protein Family, SMAC Mimetics and Cancer Treatment.

Since the acquired resistance of cells to apoptosis is one of the major hallmarks of cancer, the endogenous inhibitors of apoptosis can be regarded as promising targets in the design of anticancer therapeutics. In addition to their antiapoptotic activity, inhibitor of apoptosis proteins (IAPs) are able to regulate numerous other cell functions, including proliferation, differentiation, and migration, as well as proinflammatory and immune responses. Study of the IAP family as target molecules in targeted therapies has recently focused on SMAC mimetics as synthetic IAP antagonists that have been under development as promising therapeutics. To overview the background of IAP proteins and to focus on the development of SMAC mimetics, the present review first looks at the mechanisms of IAP proteins' antiapoptotic activities and those for controlling those activities; then the SMAC mimetics, including birinapant, LCL161, and DEBIO1143/AT-406, and their clinical trials are introduced. To further clarify the processes to exert the efficacies of SMAC mimetics, it is necessary to determine therapeutic biomarkers that predict and assess them, which may include caspases and factors in the TNFα pathway.

Nicotine receptor partial agonists for smoking cessation.

BACKGROUND: Nicotine receptor partial agonists may help people to stop smoking by a combination of maintaining moderate levels of dopamine to counteract withdrawal symptoms (acting as an agonist) and reducing smoking satisfaction (acting as an antagonist). OBJECTIVES: To review the efficacy of nicotine receptor partial agonists, including varenicline and cytisine, for smoking cessation. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group's specialised register for trials, using the terms ('cytisine' or 'Tabex' or 'dianicline' or 'varenicline' or 'nicotine receptor partial agonist') in the title or abstract, or as keywords. The register is compiled from searches of MEDLINE, EMBASE, and PsycINFO using MeSH terms and free text to identify controlled trials of interventions for smoking cessation and prevention. We contacted authors of trial reports for additional information where necessary. The latest update of the specialised register was in May 2015, although we have included a few key trials published after this date. We also searched online clinical trials registers. SELECTION CRITERIA: We included randomised controlled trials which compared the treatment drug with placebo. We also included comparisons with bupropion and nicotine patches where available. We excluded trials which did not report a minimum follow-up period of six months from start of treatment. DATA COLLECTION AND ANALYSIS: We extracted data on the type of participants, the dose and duration of treatment, the outcome measures, the randomisation procedure, concealment of allocation, and completeness of follow-up.The main outcome measured was abstinence from smoking at longest follow-up. We used the most rigorous definition of abstinence, and preferred biochemically validated rates where they were reported. Where appropriate we pooled risk ratios (RRs), using the Mantel-Haenszel fixed-effect model. MAIN RESULTS: Two trials of cytisine (937 people) found that more participants taking cytisine stopped smoking compared with placebo at longest follow-up, with a pooled risk ratio (RR) of 3.98 (95% confidence interval (CI) 2.01 to 7.87; low-quality evidence). One recent trial comparing cytisine with NRT in 1310 people found a benefit for cytisine at six months (RR 1.43, 95% CI 1.13 to 1.80).One trial of dianicline (602 people) failed to find evidence that it was effective (RR 1.20, 95% CI 0.82 to 1.75). This drug is no longer in development.We identified 39 trials that tested varenicline, 27 of which contributed to the primary analysis (varenicline versus placebo). Five of these trials also included a bupropion treatment arm. Eight trials compared varenicline with nicotine replacement therapy (NRT). Nine studies tested variations in varenicline dosage, and 13 tested usage in disease-specific subgroups of patients. The included studies covered 25,290 participants, 11,801 of whom used varenicline.The pooled RR for continuous or sustained abstinence at six months or longer for varenicline at standard dosage versus placebo was 2.24 (95% CI 2.06 to 2.43; 27 trials, 12,625 people; high-quality evidence). Varenicline at lower or variable doses was also shown to be effective, with an RR of 2.08 (95% CI 1.56 to 2.78; 4 trials, 1266 people). The pooled RR for varenicline versus bupropion at six months was 1.39 (95% CI 1.25 to 1.54; 5 trials, 5877 people; high-quality evidence). The RR for varenicline versus NRT for abstinence at 24 weeks was 1.25 (95% CI 1.14 to 1.37; 8 trials, 6264 people; moderate-quality evidence). Four trials which tested the use of varenicline beyond the 12-week standard regimen found the drug to be well-tolerated during long-term use. The number needed to treat with varenicline for an additional beneficial outcome, based on the weighted mean control rate, is 11 (95% CI 9 to 13). The most commonly reported adverse effect of varenicline was nausea, which was mostly at mild to moderate levels and usually subsided over time. Our analysis of reported serious adverse events occurring during or after active treatment suggests there may be a 25% increase in the chance of SAEs among people using varenicline (RR 1.25; 95% CI 1.04 to 1.49; 29 trials, 15,370 people; high-quality evidence). These events include comorbidities such as infections, cancers and injuries, and most were considered by the trialists to be unrelated to the treatments. There is also evidence of higher losses to follow-up in the control groups compared with the intervention groups, leading to a likely underascertainment of the true rate of SAEs among the controls. Early concerns about a possible association between varenicline and depressed mood, agitation, and suicidal behaviour or ideation led to the addition of a boxed warning to the labelling in 2008. However, subsequent observational cohort studies and meta-analyses have not confirmed these fears, and the findings of the EAGLES trial do not support a causal link between varenicline and neuropsychiatric disorders, including suicidal ideation and suicidal behaviour. The evidence is not conclusive, however, in people with past or current psychiatric disorders. Concerns have also been raised that varenicline may slightly increase cardiovascular events in people already at increased risk of those illnesses. Current evidence neither supports nor refutes such an association, but we await the findings of the CATS trial, which should establish whether or not this is a valid concern. AUTHORS' CONCLUSIONS: Cytisine increases the chances of quitting, although absolute quit rates were modest in two recent trials. Varenicline at standard dose increased the chances of successful long-term smoking cessation between two- and three-fold compared with pharmacologically unassisted quit attempts. Lower dose regimens also conferred benefits for cessation, while reducing the incidence of adverse events. More participants quit successfully with varenicline than with bupropion or with NRT. Limited evidence suggests that varenicline may have a role to play in relapse prevention. The most frequently recorded adverse effect of varenicline is nausea, but mostly at mild to moderate levels and tending to subside over time. Early reports of possible links to suicidal ideation and behaviour have not been confirmed by current research.Future trials of cytisine may test extended regimens and more intensive behavioural support.

The Past, Present, and Future of Nicotine Addiction Therapy.

The tobacco addiction treatment field is progressing through innovations in medication development, a focus on precision medicine, and application of new technologies for delivering support in real time and over time. This article reviews the evidence for combined and extended cessation pharmacotherapy and behavioral strategies including provider advice, individual counseling, group programs, the national quitline, websites and social media, and incentives. Healthcare policies are changing to offer cessation treatment to the broad population of smokers. With knowledge of the past and present, this review anticipates what is likely on the horizon in the clinical and public health effort to address tobacco addiction.