Prophylactic Trials Research Articles

Potent Antietumor Immunity in Mice Induced by Vaccination With an Ovine Atadenovirus Vector

Identification of adenoviral isolates of nonhuman origin has fostered development of vectors with potential to overcome preexisting immunity in the human population that may affect clinical applications. Ovine adenoviral isolate, OAdV287 (OAdV7), the prototype of the genus Atadenovirus, has been previously characterized as a gene delivery vector although the receptor(s) used for infection remain to be identified. Here, we report the first use of recombinant OAdV7 as a vaccine for inducing an antitumor immune response in a mouse model. Treatment of murine BMDC with OAdV7 vectors expressing ovalbumin (OVA) resulted in upregulation of costimulatory markers and production of IL-12. Splenocytes isolated from immunized mice responded to antigen restimulation in vitro by proliferation and production of IFNγ. In vivo cytotoxicity assays revealed efficient killing of antigenic peptide-pulsed target cells 1 week after immunization, with an average killing efficiency of 75%. In mice inoculated with B16-OVA tumor cells immunization with OAdV7-OVA retarded and essentially prevented tumor growth in prophylactic and therapeutic tumor trials, respectively. Generation of a robust memory response was confirmed on tumor rechallenge in the prophylactic model. Therefore, OAdV7 is a novel vector with potential for further development of tumor vaccines.

Differential modulation of cord blood and peripheral blood monocytes by intravenous immunoglobulin

Immunoglobulins (IVIG) have been shown to be useful in adults suffering from sepsis. In contrast, prophylactic and curative IVIG trials failed to show beneficial effects in neonates. We tested the hypothesis that IVIG, have different effects on monocytes from cord blood (CBMO) and peripheral blood monocytes from adults (PBMO) with respect to survival, phenotype, and function. Mononuclear cells, or purified monocytes, were cultured in 5% human serum, incubated with polyvalent IVIG (1 mg/ml), stimulated with green fluorescent protein (GFP)-labeled Escherichia coli (E. Coli-GFP), Interferon-γ (IFN-γ, 50 U/ml), or the T cell mitogen anti-CD3 monoclonal antibody, αCD3-mAb, (5 μg/ml). Phagocytosis, phenotype, T cell proliferation, and apoptosis were assessed by flow cytometry. IVIG enhanced phagocytosis in PBMO or CBMO when infected directly after isolation, while IVIG had no effect on monocytes cultured 48 h prior to infection. In contrast to PBMO, IVIG inhibited the IFN-γ mediated up-regulation of CD80, CD86, and HLA-DR on CBMO. In the presence of IVIG, stimulation with αCD3 in cord blood enhanced deletion, inhibited blast formation and CD28 up-regulation of T cells (P < 0.05 vs. T cells from adults). IVIG induced monocyte apoptosis, associated with up-regulation of Annexin V and loss of nuclear DNA, which was more pronounced in CBMO. Although phagocytosis induced cell death (PICD) was lower in CBMO (P < 0.05 vs. PBMO), the addition of IVIG enhanced PICD levels of CBMO to the extent of PBMO. IVIG inhibits co-stimulatory receptors and functions of CBMO and induces apoptosis. These findings may be of clinical relevance for the failure of IVIG benefit in neonatal sepsis.

P1-S6.03 Why are so many of our biomedical and behavioural prevention trials failing?

BackgroundWith a few exceptions, most biomedical and behavioural randomised, controlled prevention trials have failed to demonstrate efficacy. The recently reported iPrEx Trial on pre-exposure prophylaxis, the Thai prophylactic vaccine trials...

Rhetorical Strategies Used in the Reporting of Implantable Defibrillator Primary Prevention Trials

Previous studies have suggest that the authors of randomized trial reports frequently use rhetorical strategies, such as framing, the use of ratios rather than absolute values to report results, and underreporting of complications, to convince readers of treatment efficacy. The objective of this study was to determine if such rhetorical strategies were used in the publication of implantable-cardioverter defibrillator (ICD) primary prevention trials. Medline and the Cochrane Central Register of Controlled Trials were searched for all publications that described ICD primary prevention trials and that involved >100 subjects. Each publication was analyzed for evidence of message framing, the exclusive use of ratios to report outcomes, underreporting of ICD complications, and interpretation bias favoring ICD therapy. Ten publications were identified. Introductory remarks in 8 of the 10 publications cited the evaluation of ICD benefits as the sole objective and mentioned only background studies that supported ICD efficacy, suggesting message framing in support of ICD efficacy. Five publications provided no specific information about the frequency of unsuccessful ICD implantations, and 8 publications provided incomplete or no information about implantation and postimplantation complications. ICD complications were not mentioned in the discussion sections of 9 publications, and none of the publications included a comprehensive comparison of ICD benefits versus risks, consistent with interpretation bias. Ratios and statistically insignificant data were not used to emphasize ICD benefits. In conclusion, message framing, underreporting of ICD complications, and interpretation bias were used to emphasize ICD efficacy in the reporting of ICD primary prevention trials.

Use of prokinetics in the preterm infant

Functional gastrointestinal dysmotility is a common condition that affects premature infants. Delay in achievement of full enteral nutrition results in dependence on prolonged parenteral nutrition, predisposing to adverse outcomes. Studies in recent years show apparently conflicting results regarding the use of prokinetic agents in preterm infants. This review aims to evaluate these studies to determine whether use of these agents in premature infants is beneficial and justified. Randomized controlled trials in recent years have been performed to investigate the effectiveness of erythromycin in the treatment of nonobstructive gastrointestinal dysmotility in preterm infants. Overall, neither low-dose regimes nor prophylactic trials have been shown to be useful. High-dose regimes used as rescue therapy of infants with established gastrointestinal dysmotility have consistently shown clinical benefit. Theoretical risks of prolonged antibiotic use, such as emergence of antibiotic resistance and abnormal intestinal microbiota, have not been fully evaluated. Judicious use of high-dose erythromycin in premature infants as rescue therapy is probably justifiable. Further research in this area is warranted to develop newer prokinetic agents which may improve the safety profile of therapy.

Extracellular and intraneuronal HMW-AbetaOs represent a molecular basis of memory loss in Alzheimer's disease model mouse

BackgroundSeveral lines of evidence indicate that memory loss represents a synaptic failure caused by soluble amyloid β (Aβ) oligomers. However, the pathological relevance of Aβ oligomers (AβOs) as the trigger of synaptic or neuronal degeneration, and the possible mechanism underlying the neurotoxic action of endogenous AβOs remain to be determined.ResultsTo specifically target toxic AβOs in vivo, monoclonal antibodies (1A9 and 2C3) specific to them were generated using a novel design method. 1A9 and 2C3 specifically recognize soluble AβOs larger than 35-mers and pentamers on Blue native polyacrylamide gel electrophoresis, respectively. Biophysical and structural analysis by atomic force microscopy (AFM) revealed that neurotoxic 1A9 and 2C3 oligomeric conformers displayed non-fibrilar, relatively spherical structure. Of note, such AβOs were taken up by neuroblastoma (SH-SY5Y) cell, resulted in neuronal death. In humans, immunohistochemical analysis employing 1A9 or 2C3 revealed that 1A9 and 2C3 stain intraneuronal granules accumulated in the perikaryon of pyramidal neurons and some diffuse plaques. Fluoro Jade-B binding assay also revealed 1A9- or 2C3-stained neurons, indicating their impending degeneration. In a long-term low-dose prophylactic trial using active 1A9 or 2C3 antibody, we found that passive immunization protected a mouse model of Alzheimer's disease (AD) from memory deficits, synaptic degeneration, promotion of intraneuronal AβOs, and neuronal degeneration. Because the primary antitoxic action of 1A9 and 2C3 occurs outside neurons, our results suggest that extracellular AβOs initiate the AD toxic process and intraneuronal AβOs may worsen neuronal degeneration and memory loss.ConclusionNow, we have evidence that HMW-AβOs are among the earliest manifestation of the AD toxic process in mice and humans. We are certain that our studies move us closer to our goal of finding a therapeutic target and/or confirming the relevance of our therapeutic strategy.

Vaccine-induced HIV seropositivity: A problem on the rise

Background Vaccine-induced antibodies to envelope proteins frequently cause HIV seroconversion in uninfected recipients of HIV vaccine candidates and may thus have an impact on the vaccinee's ability to donate blood or acquire a life insurance policy. Objective To determine the occurrence of positive test results when commonly used HIV immunoassays are used to screen sera of HIV-uninfected volunteers who received an adjuvanted HIV-1 vaccine candidate containing HIV-1 antigens p24, reverse transcriptase, Nef and p17. Study design Sera of 50 subjects who received this polyprotein vaccine in a single center in Belgium were tested with 6 HIV screening assays and 1 confirmation test. All samples were drawn one year after the administration of the first of two vaccine doses given with one month interval. Results Forty-five (90%) sera showed a positive test result in at least one of the 7 HIV tests used. The positivity rates were 88% in the Elecsys HIV Combi assay, 74% in the ADVIA Centaur EHIV and 48% in the PRISM HIV O Plus assay. Conclusions Interpretation of HIV test results is becoming increasingly complex with the growing number of volunteers participating in prophylactic HIV vaccine trials worldwide and the rising number of viral antigens included in these vaccine candidates. The results of this study in recipients of a highly immunogenic adjuvanted polyprotein HIV vaccine candidate devoid of envelope proteins, illustrate the increasing need for approaches that can discriminate HIV infection-induced antibodies from those elicited by a vaccine.

Effective Symptomatic Medication Should Be Available in Prophylactic Trials in Cluster Headache

Effective Symptomatic Medication Should Be Available in Prophylactic Trials in Cluster Headache Peer Tfelt-Hansen MD, DMS, Peer Tfelt-Hansen MD, DMS Danish Headache Center, University of Copenhagen, Glostrup Hospital, Glostrup, DenmarkSearch for more papers by this author Peer Tfelt-Hansen MD, DMS, Peer Tfelt-Hansen MD, DMS Danish Headache Center, University of Copenhagen, Glostrup Hospital, Glostrup, DenmarkSearch for more papers by this author First published: 01 February 2011 https://doi.org/10.1111/j.1526-4610.2010.01832.xCitations: 3Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume51, Issue2February 2011Pages 307-307 RelatedInformation

Early treatment after stroke for the prevention of late epileptic seizures: A report on the problems performing a randomised placebo-controlled double-blind trial aimed at anti-epileptogenesis

Introduction Epileptic seizures in stroke patients are a common complication and adversely affect neurological outcome. We tried to perform a trial aimed at preventing the development of late poststroke seizures using levetiracetam. Levetiracetam is assumed to have anti-epileptogenic properties and might be suitable to prevent late epileptic seizures in stroke patients. Methods Stroke patients with a cortical syndrome and a modified Rankin score ≥ 3 or NIHSS ≥ 6 were treated with either levetiracetam 1500 mg daily divided in two doses or placebo during 12 weeks following stroke. Treatment was started within 7 days following stroke onset. Results Only 16 patients were included in this trial. Problems during the execution of this prophylactic trial concerned the assessment of the occurrence of epileptic seizures, a very slow inclusion rate, the use of anticonvulsive co-medication, continuation of the trial medication after discharge, and the evaluation of possible side effects of the trial medication. Discussion Due to too few participants, no conclusions could be drawn regarding the ability of levetiracetam to prevent poststroke seizures. The problems encountered during execution of this trial seem to be inherent to performing a trial aimed at preventing the development of epileptic seizures in stroke patients. Conclusions A prophylactic trial in stroke patients aimed at preventing poststroke seizures and epilepsy seems not feasible.

Are the current IHS guidelines for migraine drug trials being followed?

In 2000, the Clinical Trials Subcommittee of the International Headache Society (IHS) published the second edition of its guidelines for controlled trials of drugs in migraine. The purpose of this publication was to improve the quality of such trials by increasing the awareness amongst investigators of the methodological issues specific to this particular illness. Until now the adherence to these guidelines has not been systematically assessed. We reviewed all published controlled trials of drugs in migraine from 2002 to 2008. Eligible trials were scored for compliance with the IHS guidelines by using grading scales based on the most essential recommendations of the guidelines. The primary efficacy measure of each trial was also recorded. A total of 145 trials of acute treatment and 52 trials of prophylactic treatment were eligible for review. Of the randomized, double-blind trials, acute trials scored an average of 4.7 out of 7 while prophylactic trials scored an average of 5.6 out of 9 for compliance. Thirty-one percent of acute trials and 72% of prophylactic trials used the recommended primary efficacy measure. Fourteen percent of the reviewed trials were either not randomized or not double-blinded. Adherence to international guidelines like these of IHS is important to ensure that only high-quality trials are performed, and to provide the consensus that is required for meta analyses. The primary efficacy measure for trials of acute treatment should be “pain free” and not “headache relief”. Open-label or non-randomized trials generally have no place in the study of migraine drugs.

Still a long wait for approved HIV-protective gel

June 2013 – that’s the ‘realistic’ date by which vulnerable South African women can expect to begin using an officially approved vaginal microbicide gel that would provide them with an unprecedented tool to protect themselves from HIV infection. This is the belief of biochemist and epidemiologist, Dr Quarraisha Abdool Karim, who, together with her clinician and fellow epidemiologist husband, Professor Salim Abdool Karim, led the now world-renowned ‘proof of concept’ trial of tenofovir vaginal gel to prevent HIV infection in women. In a 3-year study of 889 women in both rural and urban KwaZulu-Natal, they demonstrated a 39% reduction in HIV infection and a 51% reduction in genital herpes infection among women who used the gel (containing 1% of the antiretroviral (ARV), tenofovir). The trial results dominated the XVIIIth International AIDS Conference in Vienna, Austria, in July and led to a clamour for confirmatory studies and fast-tracking of the gel, of which the efficacy increases with use. (Women who used the gel in more than 80% of their sex acts had a 54% reduction in HIV infections.) Unlike other HIV prophylactic trials that use available tablets, the tenofovir gel was manufactured only for the trial, run by the Durban-based Centre for AIDS Programme Research in South Africa (CAPRISA), of which the research couple are directors.

Prophylaxis and Management of Acute Radiation-Induced Skin Reactions: A Systematic Review of the Literature

Radiation therapy is a common treatment for cancer patients. One of the most common side effects of radiation is acute skin reaction (radiation dermatitis) that ranges from a mild rash to severe ulceration. Approximately 85% of patients treated with radiation therapy will experience a moderate-to-severe skin reaction. Acute radiation-induced skin reactions often lead to itching and pain, delays in treatment, and diminished aesthetic appearance-and subsequently to a decrease in quality of life. Surveys have demonstrated that a wide variety of topical, oral, and intravenous agents are used to prevent or to treat radiation-induced skin reactions. We conducted a literature review to identify trials that investigated products for the prophylaxis and management of acute radiation dermatitis. Thirty-nine studies met the pre-defined criteria, with thirty-three being categorized as prophylactic trials and six as management trials.For objective evaluation of skin reactions, the Radiation Therapy Oncology Group criteria and the U.S. National Cancer Institute Common Toxicity Criteria were the most commonly used tools (65% of the studies). Topical corticosteroid agents were found to significantly reduce the severity of skin reactions; however, the trials of corticosteroids evaluated various agents, and no clear indication about a preferred corticosteroid has emerged. Amifostine and oral enzymes were somewhat effective in preventing radiation-induced skin reactions in phase II and phase III trials respectively; further large randomized controlled trials should be undertaken to better investigate those products. Biafine cream (Ortho-McNeil Pharmaceuticals, Titusville, NJ, U.S.A.) was found not to be superior to standard regimes in the prevention of radiation-induced skin reactions (n = 6).In conclusion, the evidence is insufficient to support the use of a particular agent for the prevention and management of acute radiation-induced skin reactions. Future trials should focus on comparing agents and approaches that, in phase I and II trials, suggest efficacy. These future phase III randomized controlled trials must clearly distinguish between preventive and management strategies for radiation-induced dermatitis. Only then can evidence-based guidelines be developed, with the hope of standardizing the approach across centres and of improving the prevention and management of radiation-induced dermatitis.

Timing of implantation of cardioverter-defibrillator after acute myocardial infarction

may also partly explain the negative results of studies using risk profiling of patients early after AMI. Secondly, the two negative studies used other risk stratification methods in addition to measurement of LVEF in their study designs. It is possible that these risk stratification methods do not specifically reflect an increased risk of arrhythmic events but are more closely related to increased risk of progressive heart failure. For example, reduced heart rate variability, elevated heart rate, and the presence of non-sustained ventricular tachycardia measured in the early convalescent phase of AMI were more closely associated with increased risk of non-arrhythmic than arrhythmic death in a large observational study. 9 Therefore, both the DINAMIT and IRIS trials possibly included patients at high risk of non-arrhythmic death in their trials. Although the incidence of sudden cardiac death was reduced in these trials, the increased rate of nonarrhythmic deaths in the ICD group counterbalanced this beneficial effect. It can be speculated that patients included in the DINAMIT and IRIS trials were on the ‘slippery slope’, anyway, and died from non-arrhythmic death, probably due to progressive heart failure, despite the protection from fatal arrhythmic events. The other prophylactic ICD trials have shown that although patients with heart failure have an overall benefit from prophylactic ICD implantation, those receiving shocks have a substantially increased risk of non-sudden death. Multicentre unsustained tachycardia trial (MUSTT) was a randomized ICD trial evaluating the ability of electrophysiologically guided antiarrhythmic therapy to reduce arrhythmic death or cardiac arrest in patients with LVEF ≤ 40%, coronary artery disease, and spontaneous non-sustained ventricular tachycardia

Invasive Aspergillosis in Solid Organ Transplant Recipients

This chapter discusses the current status and evolving trends in the epidemiology, risk factors, diagnostic laboratory assays, and the approach to antifungal prophylaxis and treatment of invasive aspergillosis in Solid Organ Transplant (SOT) recipients. Most invasive fungal infections in these high-risk patients occur within the first month posttransplant; the median time to onset of invasive aspergillosis after renal replacement therapy and retransplantation was 13 and 28 days, respectively, in one study. Other factors associated with invasive aspergillosis in liver transplant recipients include transplantation for fulminate hepatic failure, cytomegalovirus (CMV) infection, and prolonged intensive care unit stay. A retrospective survey documented invasive pulmonary aspergillosis in 7.5% (19/251) of lung transplant recipients, of whom 47% (9/19) had disseminated aspergillosis. In a survey of antifungal prophylactic strategies in lung transplant units in the United States, aerosolized amphotericin B was the most frequently employed antifungal prophylactic agent. In order of preference, the prophylactic agents used in lung transplant centers in this study were inhaled amphotericin B (61%), itraconazole (46%), parenteral amphotericin formulations (25%), and fluconazole (21%); many centers used more than one agent. Preemptive therapy, where antifungal prophylaxis is directed towards lung transplant recipients colonized with Aspergillus spp. immediately before or within 6 to 9 months after transplantation, is another approach to the prevention of invasive aspergillosis in lung transplant recipients.

FDA guidance on prophylactic DNA vaccines: Analysis and recommendations

The FDA has been regulating the conduct of prophylactic DNA vaccine trials in the US for nearly 15 years. This work describes the evolution of FDA policy over that period, the status of current regulatory guidance, and provides recommendations for further changes to facilitate development in this field.

P14-13. Long-term follow-up of study participants in HIV prophylactic vaccine clinical trials in Africa

P14-13. Long-term follow-up of study participants in HIV prophylactic vaccine clinical trials in Africa

Effectiveness and safety of isoniazid chemoprophylaxis for HIV-1 infected patients from Rio de Janeiro

The clinical and epidemiological characteristics, adverse events, treatment adherence and effectiveness of isoniazid chemoprophylaxis were analyzed in a cohort of 138 tuberculosis/HIV-coinfected patients. An open, non-randomized, pragmatic prophylactic trial was conducted on adult patients with a normal chest X-ray and positive tuberculin skin test (>or= 5 mm) who received isoniazid chemoprophylaxis (300 mg/day) for six months. The mean of follow up was 2.8 years (SD 1.3). Adherence to chemoprophylaxis was 87.7% (121/138). Only one patient presented tuberculosis after the end of chemoprophylaxis, corresponding to 0.3 cases per 100 persons per year. The relative risk of some adverse effects was 4.6 times higher (95% CI: 1.9-11.5) in patients with positive anti-HCV serology (4/9, 44.4%) compared to those with negative serology (12/129, 9.6%) (p = 0.002). This study provides evidence regarding the effectiveness and safety of a short and self-administered isoniazid regimen. We recommend the implementation of this routine by health service practitioners.

Placebo Efficacy in Childhood and Adolescence Migraine: An Analysis of Double-Blind and Placebo-Controlled Studies

Studies on the treatment of migraine in children and adolescents are rare and difficult to design. In particular, the high placebo response in some trials makes it difficult to prove efficacy of a verum drug. We analysed all available placebo-controlled trials on acute and on prophylactic migraine treatment in children and adolescents with respect to different placebo rates (pain free and pain relief at 2 h; rate of responders with >or= 50% attack frequency decrease). We identified eight crossover and 11 parallel group trials on acute treatment. The placebo response rates were considerably lower in crossover trials than in parallel group trials (19.2% vs. 27.1% for pain free after 2 h and 39.4% vs. 56.9% for pain relief after 2 h). In the 10 prophylactic trials included in this analysis, only a small trend towards a lower placebo rate in crossover trials could be observed. Further significant factors associated with a lower placebo rate in childhood and adolescence trials on the acute treatment of migraine were single-centre (vs. multicentre) trials and small sample size. Age and sex were not associated with the placebo response. Our study suggests that parallel group trials on the acute treatment of migraine in children and adolescents show a very low therapeutic gain due to a high placebo rate. The verum response rates, however, are very similar to those seen in adulthood trials. In conclusion, trial designs on the acute and prophylactic treatment of migraine in children and adolescents should consider the specific findings of this analysis in order to exhibit a higher probability of showing significant differences between placebo and verum drug.

Granulocyte-macrophage colony stimulating factor administered as prophylaxis for reduction of sepsis in extremely preterm, small for gestational age neonates (the PROGRAMS trial): a single-blind, multicentre, randomised controlled trial

Systemic sepsis is a major cause of death in preterm neonates. There are compelling theoretical reasons why treatment with haemopoietic colony-stimulating factors might reduce sepsis and improve outcomes, and as a consequence these agents have entered into use in neonatal medicine without adequate evidence. We assessed whether granulocyte-macrophage colony stimulating factor (GM-CSF) administered as prophylaxis to preterm neonates at high risk of neutropenia would reduce sepsis, mortality, and morbidity. We undertook a single-blind, multicentre, randomised controlled trial in 26 centres between June, 2000, and June, 2006. 280 neonates of below or equal to 31 weeks' gestation and below the 10th centile for birthweight were randomised within 72 h of birth to receive GM-CSF 10 microg/kg per day subcutaneously for 5 days or standard management. From recruitment to day 28 a detailed daily clinical record form was completed by the treating clinicians. Primary outcome was sepsis-free survival to 14 days from trial entry. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN42553489. Neutrophil counts after trial entry rose significantly more rapidly in infants treated with GM-CSF than in control infants during the first 11 days (difference between neutrophil count slopes 0.34 x 10(9)/L/day; 95% CI 0.12-0.56). There was no significant difference in sepsis-free survival for all infants (93 of 139 treated infants, 105 of 141 control infants; difference -8%, 95% CI -18 to 3). A meta-analysis of this trial and previous published prophylactic trials showed no survival benefit. Early postnatal prophylactic GM-CSF corrects neutropenia but does not reduce sepsis or improve survival and short-term outcomes in extremely preterm neonates.

An update of prophylactic human papillomavirus L1 virus-like particle vaccine clinical trial results

This review focuses on recent publications of clinical trials of two prophylactic human papillomavirus (HPV) vaccines: Gardasil ® (Merck & Co., Inc., Whitehouse Station, NJ USA), a quadrivalent vaccine containing L1 virus-like particles (VLPs) of types -6, 11, 16, and 18, and Cervarix™ (GlaxoSmithKline Biologicals, Rixensart, Belgium), a bivalent vaccine containing VLPs of types -16 and 18. In efficacy trials involving young women, both vaccines produced outstanding efficacy against primary and secondary endpoints associated with the vaccine type HPVs and were highly and consistently immunogenic. Both had excellent safety records and, as expected, the most frequent vaccine-related adverse were mild to moderate injection site sequelae. No evidence of waning protection was observed after four years for endpoints examined ranging from incident infection to cervical intraepithelial neoplasia grade 3 associated with the vaccine type HPVs. Gardasil ® was also highly efficacious at preventing vaginal/vulvar lesions and genital warts. However, neither vaccine demonstrated therapeutic efficacy against prevalent infections or lesions, regardless of the associated HPV type. Cervarix™ has shown limited cross-protection against infection with specific closely related types while preliminary results of limited cross-protection have been presented for Gardasil ®. As expected, more limited efficacy was noted for both vaccines when women with prevalent infection were included or endpoints associated with any HPV type were evaluated. Immunological bridging trials involving adolescent girls and boys were also recently published. For both vaccines, serum VLP antibody levels in girls were non-inferior to those generated in young women and antibody response to Gardasil ® was also non-inferior in boys. The results of these studies have led to the approval of Gardasil ® and Cervarix™ by national regulatory agencies in a number of countries.