Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 58
Filtrar
1.
Lancet Glob Health ; 12(3): e491-e499, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38365419

RESUMO

BACKGROUND: The first randomised controlled trial of single-dose human papillomavirus (HPV) vaccine efficacy, the Kenya single-dose HPV-vaccine efficacy (KEN SHE) trial, showed greater than 97% efficacy against persistent HPV16 and HPV18 infection at 36 months among women in Kenya. We compared antibody responses after one dose of HPV vaccine in the Dose Reduction Immunobridging and Safety Study (DoRIS), the first randomised trial of the single- dose regimen in girls aged 9-14 years, the target age range for vaccination, with those after one dose of the same vaccine in KEN SHE. METHODS: In the DoRIS trial, 930 girls aged 9-14 years in Tanzania were randomly assigned to one, two, or three doses of the 2-valent vaccine (Cervarix) or the 9-valent vaccine (Gardasil-9). The proportion seroconverting and geometric mean concentrations (GMCs) at month 24 after one dose were compared with those in women aged 15-20 years who were randomly assigned to one dose of the same vaccines at the same timepoint in KEN SHE. Batched samples were tested together by virus-like particle ELISA for HPV16 and HPV18 IgG antibodies. Non-inferiority of GMC ratios (DoRIS trial:KEN SHE) was predefined as a lower bound of the 95% CI less than 0·50. FINDINGS: Month 24 HPV16 and HPV18 antibody GMCs in DoRIS were similar or higher than those in KEN SHE. 2-valent GMC ratios were 0·90 (95% CI 0·72-1·14) for HPV16 and 1·02 (0·78-1·33) for HPV18. 9-valent GMC ratios were 1·44 (95% CI 1·14-1·82) and 1·47 (1·13-1·90), respectively. Non-inferiority of antibody GMCs and seropositivity was met for HPV16 and HPV18 for both vaccines. INTERPRETATION: HPV16 and HPV18 immune responses in young girls 24 months after a single dose of 2-valent or 9-valent HPV vaccine were comparable to those in young women who were randomly assigned to a single dose of the same vaccines and in whom efficacy had been shown. A single dose of HPV vaccine, when given to girls in the target age range for vaccination, induces immune responses that could be effective against persistent HPV16 and HPV18 infection at least two years after vaccination. FUNDING: The UK Department of Health and Social Care, the Foreign, Commonwealth, & Development Office, the Global Challenges Research Fund, the UK Medical Research Council and Wellcome Trust Joint Global Health Trials scheme, the Bill and Melinda Gates Foundation, the US National Cancer Institute; the US National Institutes of Health, and the Francis and Dorothea Reed Endowed Chair in Infectious Diseases. TRANSLATION: For the KiSwahili translation of the abstract see Supplementary Materials section.


Assuntos
Infecções por Papillomavirus , Vacinas contra Papillomavirus , Feminino , Humanos , Anticorpos Antivirais , Infecções por Papillomavirus/prevenção & controle , Tanzânia , Redução da Medicação , Quênia , Papillomavirus Humano 16 , Papillomavirus Humano 18 , Ensaios Clínicos Controlados Aleatórios como Assunto
2.
Tumour Virus Res ; 15: 200250, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36682539

RESUMO

This article reviews human papillomavirus-associated mucosal high-grade pre-cancers and their management. It examines pre-cancer classification systems, the natural history of HPV-associated pre-cancers, the various types of management and treatment for HPV pre-cancers, the various mucosal site-specific considerations, and then some of the unresolved issues. Different conclusions are reached for each of the relevant mucosal sites, which are cervix, vagina, vulva, anus, penis and oro-pharynx, and indeed there are differing volumes of evidence relating to each of these sites, and thus differing degrees of certainty/uncertainty in the recommendations.


Assuntos
Neoplasias , Infecções por Papillomavirus , Masculino , Feminino , Humanos , Papillomavirus Humano , Infecções por Papillomavirus/terapia , Papillomaviridae , Colo do Útero
3.
Lancet Glob Health ; 10(10): e1473-e1484, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36113531

RESUMO

BACKGROUND: An estimated 15% of girls aged 9-14 years worldwide have been vaccinated against human papillomavirus (HPV) with the recommended two-dose or three-dose schedules. A one-dose HPV vaccine schedule would be simpler and cheaper to deliver. We report immunogenicity and safety results of different doses of two different HPV vaccines in Tanzanian girls. METHODS: In this open-label, randomised, phase 3, non-inferiority trial, we enrolled healthy schoolgirls aged 9-14 years from Government schools in Mwanza, Tanzania. Eligible participants were randomly assigned to receive one, two, or three doses of either the 2-valent vaccine (Cervarix, GSK Biologicals, Rixensart) or the 9-valent vaccine (Gardasil-9, Sanofi Pasteur MSD, Lyon). The primary outcome was HPV 16 specific or HPV 18 specific seropositivity following one dose compared with two or three doses of the same HPV vaccine 24 months after vaccination. Safety was assessed as solicited adverse events up to 30 days after each dose and unsolicited adverse events up to 24 months after vaccination or to last study visit. The primary outcome was done in the per-protocol population, and safety was analysed in the total vaccinated population. This study was registered in ClinicalTrials.gov, NCT02834637. FINDINGS: Between Feb 23, 2017, and Jan 6, 2018, we screened 1002 girls for eligibility. 72 girls were excluded. 930 girls were enrolled and randomly assigned to receive one dose of Cervarix (155 participants), two doses of Cervarix (155 participants), three doses of Cervarix (155 participants), one dose of Gardasil-9 (155 participants), two doses of Gardasil-9 (155 participants), or three doses of Gardasil-9 (155 participants). 922 participants received all scheduled doses within the defined window (three withdrew, one was lost to follow-up, and one died before completion; two received their 6-month doses early, and one received the wrong valent vaccine in error; all 930 participants were included in the total vaccinated cohort). Retention at 24 months was 918 (99%) of 930 participants. In the according-to-protocol cohort, at 24 months, 99% of participants who received one dose of either HPV vaccine were seropositive for HPV 16 IgG antibodies, compared with 100% of participants who received two doses, and 100% of participants who received three doses. This met the prespecified non-inferiority criteria. Anti-HPV 18 seropositivity at 24 months did not meet non-inferiority criteria for one dose compared to two doses or three doses for either vaccine, although more than 98% of girls in all groups had HPV 18 antibodies. 53 serious adverse events (SAEs) were experienced by 42 (4·5%) of 930 girls, the most common of which was hospital admission for malaria. One girl died of malaria. Number of events was similar between groups and no SAEs were considered related to vaccination. INTERPRETATION: A single dose of the 2-valent or 9-valent HPV vaccine in girls aged 9-14 years induced robust immune responses up to 24 months, suggesting that this reduced dose regimen could be suitable for prevention of HPV infection among girls in the target age group for vaccination. FUNDING: UK Department for International Development/UK Medical Research Council/Wellcome Trust Joint Global Health Trials Scheme, The Bill & Melinda Gates Foundation, and the US National Cancer Institute. TRANSLATION: For the KiSwahili translation of the abstract see Supplementary Materials section.


Assuntos
Infecções por Papillomavirus , Vacinas contra Papillomavirus , Feminino , Vacina Quadrivalente Recombinante contra HPV tipos 6, 11, 16, 18 , Papillomavirus Humano 18 , Humanos , Imunoglobulina G , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/efeitos adversos , Tanzânia
4.
Lancet Glob Health ; 10(10): e1485-e1493, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36113532

RESUMO

BACKGROUND: Human papillomavirus (HPV) vaccines are given as a two-dose schedule in children aged 9-14 years, or as three doses in older individuals. We compared antibody responses after one dose of HPV vaccine in the Dose Reduction Immunobridging and Safety Study (DoRIS), a randomised trial of different HPV vaccine schedules in Tanzania, to those from two observational HPV vaccine trials that found high efficacy of one dose up to 11 years against HPV16 and HPV18 (Costa Rica Vaccine Trial [CVT] and Institutional Agency for Research on Cancer [IARC] India trial). METHODS: In this immunobridging analysis of an open-label randomised controlled trial, girls were recruited from 54 government schools in Mwanza, Tanzania, into the DoRIS trial. Girls were eligible if they were aged 9-14 years, healthy, and HIV negative. Participants were randomly assigned (1:1:1:1:1:1), using permutated block sizes of 12, 18, and 24, to one, two, or three doses of the 2-valent vaccine (Cervarix, GSK Biologicals, Rixensart, Belgium) or the 9-valent vaccine (Gardasil 9, Sanofi Pasteur MSD, Lyon, France). For this immunobridging analysis, the primary objective was to compare geometric mean concentrations (GMCs) at 24 months after one dose in the per-protocol population compared with in historical cohorts: the one-dose 2-valent vaccine group in DoRIS was compared with recipients of the 2-valent vaccine Cervarix from CVT and the one-dose 9-valent vaccine group in DoRIS was compared with recipients of the 4-valent vaccine Gardasil (Merck Sharp & Dohme, Whitehouse Station, NJ, USA) from the IARC India trial. Samples were tested together with virus-like particle ELISA for HPV16 and HPV18 IgG antibodies. Non-inferiority of GMC ratios (DoRIS trial vs historical cohort) was predefined as when the lower bound of the 95% CI was greater than 0·50. This study is registered with ClinicalTrials.gov, NCT02834637. FINDINGS: Between Feb 23, 2017, and Jan 6, 2018, we screened 1002 girls for eligibility, of whom 930 were enrolled into DoRIS and 155 each were assigned to one dose, two doses, or three doses of 2-valent vaccine, or one dose, two doses, or three doses of 9-valent vaccine. 154 (99%) participants in the one-dose 2-valent vaccine group (median age 10 years [IQR 9-12]) and 152 (98%) in the one-dose 9-valent vaccine group (median age 10 years [IQR 9-12]) were vaccinated and attended the 24 month visit, and so were included in the analysis. 115 one-dose recipients from the CVT (median age 21 years [19-23]) and 139 one-dose recipients from the IARC India trial (median age 14 years [13-16]) were included in the analysis. At 24 months after vaccination, GMCs for HPV16 IgG antibodies were 22·9 international units (IU) per mL (95% CI 19·9-26·4; n=148) for the DoRIS 2-valent vaccine group versus 17·7 IU/mL (13·9-22·5; n=97) for the CVT (GMC ratio 1·30 [95% CI 1·00-1·68]) and 13·7 IU/mL (11·9-15·8; n=145) for the DoRIS 9-valent vaccine group versus 6·7 IU/mL (5·5-8·2; n=131) for the IARC India trial (GMC ratio 2·05 [1·61-2·61]). GMCs for HPV18 IgG antibodies were 9·9 IU/mL (95% CI 8·5-11·5: n=141) for the DoRIS 2-valent vaccine group versus 8·0 IU/mL (6·4-10·0; n=97) for the CVT trial (GMC ratio 1·23 [95% CI 0·95-1·60]) and 5·7 IU/mL (4·9-6·8; n=136) for the DoRIS 9-valent vaccine group versus 2·2 IU/mL (1·9-2·7; n=129) for the IARC India trial (GMC ratio 2·12 [1·59-2·83]). Non-inferiority of antibody GMCs was met for each vaccine for both HPV16 and HPV18. INTERPRETATION: One dose of HPV vaccine in young girls might provide sufficient protection against persistent HPV infection. A one-dose schedule would reduce costs, simplify vaccine delivery, and expand access to the vaccine. FUNDING: UK Department for International Development/UK Medical Research Council/Wellcome Trust Joint Global Health Trials Scheme, The Bill & Melinda Gates Foundation, and the US National Cancer Institute. TRANSLATION: For the KiSwahili translation of the abstract see Supplementary Materials section.


Assuntos
Infecções por Papillomavirus , Vacinas contra Papillomavirus , Adolescente , Adulto , Idoso , Criança , Redução da Medicação , Feminino , Vacina Quadrivalente Recombinante contra HPV tipos 6, 11, 16, 18 , Papillomavirus Humano 16 , Humanos , Imunoglobulina G , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/prevenção & controle , Tanzânia , Adulto Jovem
5.
Wellcome Open Res ; 7: 200, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37252616

RESUMO

Background: The leishmaniases are neglected tropical diseases caused by various Leishmania parasite species transmitted by sand flies. They comprise a number of systemic and cutaneous syndromes including kala-azar (visceral leishmaniasis, VL), cutaneous leishmaniasis (CL), and post-kala-azar dermal leishmaniasis (PKDL). The leishmaniases cause significant mortality (estimated 20 - 50,000 deaths annually), morbidity, psychological sequelae, and healthcare and societal costs. Treatment modalities remain difficult. E.g., East African PKDL requires 20 days of intravenous therapy, and frequently relapsing VL is seen in the setting of HIV and immunodeficiency. We developed a new therapeutic vaccine, ChAd63-KH for VL / CL / PKDL and showed it to be safe and immunogenic in a phase 1 trial in the UK, and in a phase 2a trial in PKDL patients in Sudan.    Methods: This is a randomised double-blind placebo-controlled phase 2b trial to assess the therapeutic efficacy and safety of ChAd63-KH in patients with persistent PKDL in Sudan. 100 participants will be randomly assigned 1:1 to receive placebo or ChAd63-KH (7.5 x10 10vp i.m.) at a single time point. Follow up is for 120 days after dosing and we will compare the clinical evolution of PKDL, as well as the humoral and cellular immune responses between the two arms. Discussion: Successful development of a therapeutic vaccine for leishmaniasis would have wide-ranging direct and indirect healthcare benefits that could be realized rapidly. For PKDL patients, an effective therapeutic vaccination used alone   would have very significant clinical value, reducing the need for extensive hospitalization and chemotherapy. Combining vaccine with drug (immuno-chemotherapy) might significantly increase the effective life of new drugs, with lower dose / abbreviated regimens helping to limit the emergence of drug resistance. If therapeutic benefit of ChAd63-KH can be shown in PKDL further evaluation of the vaccine in other forms of leishmaniasis should be considered. Clinicaltrials.gov registration: NCT03969134.

6.
Expert Rev Vaccines ; 20(11): 1419-1430, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34727814

RESUMO

INTRODUCTION: The leishmaniases represent a group of parasitic diseases caused by infection with one of several species of Leishmania parasites. Disease presentation varies because of differences in parasite and host genetics and may be influenced by additional factors such as host nutritional status or co-infection. Studies in experimental models of Leishmania infection, vaccination of companion animals and human epidemiological data suggest that many forms of leishmaniasis could be prevented by vaccination, but no vaccines are currently available for human use. AREAS COVERED: We describe some of the existing roadblocks to the development and implementation of an effective leishmaniasis vaccine, based on a review of recent literature found on PubMed, BioRxiv and MedRxiv. In addition to discussing scientific unknowns that hinder vaccine candidate identification and selection, we explore gaps in knowledge regarding the commercial and public health value propositions underpinning vaccine development and provide a route map for future research and advocacy. EXPERT OPINION: Despite significant progress, leishmaniasis vaccine development remains hindered by significant gaps in understanding that span the vaccine development pipeline. Increased coordination and adoption of a more holistic view to vaccine development will be required to ensure more rapid progress in the years ahead.


Assuntos
Leishmania , Vacinas contra Leishmaniose , Leishmaniose , Animais , Humanos , Leishmaniose/prevenção & controle , Vacinação
7.
Wellcome Open Res ; 6: 168, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34693027

RESUMO

Background: Leishmaniasis is a globally important yet neglected parasitic disease transmitted by phlebotomine sand flies. With new candidate vaccines in or near the clinic, a controlled human challenge model (CHIM) using natural sand fly challenge would provide a method for early evaluation of prophylactic efficacy. Methods : We evaluated the biting frequency and adverse effects resulting from exposure of human volunteers to bites of either Phlebotomus papatasi or P. duboscqi, two natural vectors of Leishmania major. 12 healthy participants were recruited (mean age 40.2 ± 11.8 years) with no history of significant travel to regions where L. major-transmitting sand flies are prevalent. Participants were assigned to either vector by 1:1 allocation and exposed to five female sand flies for 30 minutes in a custom biting chamber. Bite frequency was recorded to confirm a bloodmeal was taken. Participant responses and safety outcomes were monitored using a visual analogue scale (VAS), clinical examination, and blood biochemistry. Focus groups were subsequently conducted to explore participant acceptability. Results: All participants had at least one successful sand fly bite with none reporting any serious adverse events, with median VAS scores of 0-1/10 out to day 21 post-sand fly bite. Corresponding assessment of sand flies confirmed that for each participant at least 1/5 sand flies had successfully taken a bloodmeal (overall mean 3.67±1.03 bites per participant). There was no significant difference between P. papatasi and P. duboscqi in the number of bites resulting from 5 sand flies applied to human participants (3.3±0.81 vs 3.00±1.27 bites per participant; p=0.56) .  In the two focus groups (n=5 per group), themes relating to positive participant-reported experiences of being bitten and the overall study, were identified. Conclusions: These results validate a protocol for achieving successful sand fly bites in humans that is safe, well-tolerated and acceptable for participants. Clinicaltrials.gov registration: NCT03999970 (27/06/2019).

8.
Expert Rev Vaccines ; 20(11): 1407-1418, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34664543

RESUMO

INTRODUCTION: Leishmaniasis is a neglected tropical disease that is defined by the World Health Organization as vaccine preventable. Although several new candidate vaccines are in development, no vaccine has successfully reached the market for human use. Several species of Leishmania cause human disease and have co-evolved with their respective sand fly vectors. These unique relationships have implications for initiation of infection and vaccine development. An approach to vaccine development for many infectious diseases is the use of controlled human infection models (CHIMs). AREAS COVERED: We describe the history and recent development of experimental and deliberate infection using Leishmania in humans and the rationale for developing a new sand fly-initiated CHIM to progress leishmaniasis vaccine development. Examples from other infectious diseases are discussed in the context of the development of a new leishmaniasis CHIM. We also reflect upon the manufacture of the challenge agent, practical considerations, safety, ethics, and regulatory issues. EXPERT OPINION: A new cutaneous Leishmania CHIM is being developed to enable testing of vaccines in the development pipeline. Questions remain about the use of such CHIMs to determine effectiveness of vaccines against visceral leishmaniasis. However, such a CHIM will be invaluable in expediting time to market for vaccines.


Assuntos
Leishmania , Vacinas contra Leishmaniose , Leishmaniose Visceral , Leishmaniose , Psychodidae , Animais , Humanos , Leishmaniose/prevenção & controle , Leishmaniose Visceral/prevenção & controle , Pele
9.
Res Involv Engagem ; 7(1): 33, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-34053461

RESUMO

BACKGROUND: A controlled human infection model (CHIM) involves deliberate exposure of volunteers to pathogens to assess their response to new therapies at an early stage of development. We show here how we used public involvement to help shape the design of a CHIM to support future testing of candidate vaccines for the neglected tropical disease cutaneous leishmaniasis, a disease transmitted by the bite of infected sand flies in tropical regions. METHODS: We undertook a public involvement (PI) consultation exercise to inform development of a study to test the safety and effectiveness of a sand fly biting protocol using uninfected sand flies (FLYBITE: ClinicalTrials.gov ID NCT03999970 ) and a CHIM using Leishmania major-infected sand flies (LEISH_Challenge: ClinicalTrials.gov ID NCT04512742 ), both taking place in York, UK. We involved 10 members of the public including a patient research ambassador and a previous CHIM volunteer. The session took place at The University of York, UK and examined draft study volunteer-facing material and included the CHIM study design, potential adverse events and therapeutic interventions at study endpoints. A discussion of the scientific, ethical, humanitarian and economic basis for the project was presented to the participants to provoke discourse. An inductive, thematic analysis was used to identify the participants' key concerns. RESULTS: Themes were identified relating to i) quality of volunteer-facing written information, ii) improving study design, and iii) factors to motivate involvement in the research. Group participants responded positively to the overall study aims. Initial concerns were expressed about potential risks of study involvement, but further explanation of the science and mitigations of risk secured participant support. Participants provided advice and identified improved terminology to inform the volunteer-facing material. Lastly, treatment options were discussed, and excision of any cutaneous lesion was favoured over alternatives as a treatment. CONCLUSION: The consultation exercise provided invaluable information which led to improved study design and enhanced clarity in the volunteer-facing material. The session also reinforced the need to maintain public trust in scientific rigour prior to initiation of any study. The investigators hope that this description strengthens understanding of PI in clinical research, and encourages its use within other studies.


Our research team is designing a type of research study known as a controlled human infection model (CHIM). In CHIM studies, volunteers are exposed to infections on purpose and then studied to help understand diseases. Similar experiments, where humans are infected deliberately, have been used for hundreds of years to help test treatments. CHIM studies have already been used more recently to help test vaccines for diseases such as malaria.The disease leishmaniasis, a disease affecting millions each year, is spread by the bite of an infected sand fly in tropical countries. There are currently no vaccines for leishmaniasis that are available for use in humans. It is thought that by using CHIM studies, new vaccines might be tested and then approved more quickly. Scientific researchers have had many discussions about how useful CHIM studies are, especially in terms of the science behind them, the safety of volunteers and the ethics of these studies. Researchers also understand how important it is to involve the public in designing and carrying out research, especially studies involving humans, to get an independent point-of-view. We have therefore involved the public, in some parts of designing this research, in a group discussion. We also included a person who has already taken part in a different CHIM study. These discussions have had an important effect and have changed how we plan to carry out our future research studies. We also hope that this description will encourage other researchers to include the public when planning future research.

10.
Mol Ther ; 29(7): 2366-2377, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-33781913

RESUMO

Post-kala-azar dermal leishmaniasis (PKDL) is a chronic, stigmatizing skin condition occurring frequently after apparent clinical cure from visceral leishmaniasis. Given an urgent need for new treatments, we conducted a phase IIa safety and immunogenicity trial of ChAd63-KH vaccine in Sudanese patients with persistent PKDL. LEISH2a (ClinicalTrials.gov: NCT02894008) was an open-label three-phase clinical trial involving sixteen adult and eight adolescent patients with persistent PKDL (median duration, 30 months; range, 6-180 months). Patients received a single intramuscular vaccination of 1 × 1010 viral particles (v.p.; adults only) or 7.5 × 1010 v.p. (adults and adolescents), with primary (safety) and secondary (clinical response and immunogenicity) endpoints evaluated over 42-120 days follow-up. AmBisome was provided to patients with significant remaining disease at their last visit. ChAd63-KH vaccine showed minimal adverse reactions in PKDL patients and induced potent innate and cell-mediated immune responses measured by whole-blood transcriptomics and ELISpot. 7/23 patients (30.4%) monitored to study completion showed >90% clinical improvement, and 5/23 (21.7%) showed partial improvement. A logistic regression model applied to blood transcriptomic data identified immune modules predictive of patients with >90% clinical improvement. A randomized controlled trial to determine whether these clinical responses were vaccine-related and whether ChAd63-KH vaccine has clinical utility is underway.


Assuntos
Antígenos de Protozoários/imunologia , Linfócitos T CD8-Positivos/imunologia , Leishmania/imunologia , Vacinas contra Leishmaniose/administração & dosagem , Leishmaniose Cutânea/prevenção & controle , Vacinas Sintéticas/administração & dosagem , Adenovirus dos Símios/genética , Adolescente , Adulto , Criança , Feminino , Humanos , Injeções Intramusculares , Leishmania/isolamento & purificação , Vacinas contra Leishmaniose/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Masculino , Prognóstico , Vacinas Sintéticas/imunologia , Adulto Jovem
11.
Nat Commun ; 12(1): 215, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431825

RESUMO

Leishmaniasis is widely regarded as a vaccine-preventable disease, but the costs required to reach pivotal Phase 3 studies and uncertainty about which candidate vaccines should be progressed into human studies significantly limits progress in vaccine development for this neglected tropical disease. Controlled human infection models (CHIMs) provide a pathway for accelerating vaccine development and to more fully understand disease pathogenesis and correlates of protection. Here, we describe the isolation, characterization and GMP manufacture of a new clinical strain of Leishmania major. Two fresh strains of L. major from Israel were initially compared by genome sequencing, in vivo infectivity and drug sensitivity in mice, and development and transmission competence in sand flies, allowing one to be selected for GMP production. This study addresses a major roadblock in the development of vaccines for leishmaniasis, providing a key resource for CHIM studies of sand fly transmitted cutaneous leishmaniasis.


Assuntos
Leishmania major/fisiologia , Leishmaniose Cutânea/parasitologia , Animais , Modelos Animais de Doenças , Humanos , Insetos Vetores/parasitologia , Israel , Leishmania major/genética , Leishmania major/crescimento & desenvolvimento , Leishmaniose Cutânea/transmissão , Camundongos Endogâmicos BALB C , Parasitos/genética , Filogenia , Psychodidae/parasitologia , Sequenciamento Completo do Genoma
12.
Contemp Clin Trials ; 101: 106266, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33421649

RESUMO

BACKGROUND: Human papillomavirus (HPV) infection is the primary cause of cervical cancer. In 2018, the World Health Organization (WHO) Director General announced his commitment to eliminate cervical cancer, with HPV vaccination as a priority. However, the costs of setting up a multi-dose HPV vaccination programme remain a barrier to its introduction. METHODS/DESIGN: We are conducting a randomised-controlled trial of reduced dose schedules of HPV vaccine in Tanzania to establish whether a single dose produces immune responses that will be effective in preventing cervical cancer. 930 girls aged 9-14 years in Mwanza, Tanzania, were randomised to one of 6 arms, comprising 3 different dose schedules of the 2-valent (Cervarix) and 9-valent (Gardasil-9) HPV vaccines: 3 doses; 2 doses given 6 months apart; or a single dose. All participants will be followed for 36 months; those in the 1 and 2 dose arms will be followed for 60 months. Trial outcomes focus on vaccine immune responses including HPV 16/18-specific antibody levels, antibody avidity, and memory B cell responses. Results will be immunobridged to historical cohorts of girls and young women in whom efficacy has been demonstrated. DISCUSSION: This is the first randomised trial of the single dose HPV vaccine schedule in the target age group. The trial will allow us to examine the quality and durability of immune responses of reduced dose schedules in a population with high burden of malaria and other infections that may affect vaccine immune responses. Initial results (24 months) are expected to be published in early 2021.


Assuntos
Infecções por Papillomavirus , Vacinas contra Papillomavirus , Neoplasias do Colo do Útero , Adolescente , Feminino , Papillomavirus Humano 16 , Papillomavirus Humano 18 , Humanos , Infecções por Papillomavirus/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto , Tanzânia , Neoplasias do Colo do Útero/prevenção & controle
13.
Health Technol Assess ; 24(47): 1-86, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32975189

RESUMO

BACKGROUND: The comparative efficacy, and cost-effectiveness, of imiquimod or podophyllotoxin cream, either alone or in combination with the quadrivalent HPV vaccine (Gardasil®, Merck Sharp & Dohme Corp., Merck & Co., Inc., Whitehouse Station, NJ, USA) in the treatment and prevention of recurrence of anogenital warts is not known. OBJECTIVE: The objective was to compare the efficacy of imiquimod and podophyllotoxin creams to treat anogenital warts and to assess whether or not the addition of quadrivalent human papillomavirus vaccine increases wart clearance or prevention of recurrence. DESIGN: A randomised, controlled, multicentre, partially blinded factorial trial. Participants were randomised equally to four groups, combining either topical treatment with quadrivalent human papillomavirus vaccine or placebo. Randomisation was stratified by gender, a history of previous warts and human immunodeficiency virus status. There was an accompanying economic evaluation, conducted from the provider perspective over the trial duration. SETTING: The setting was 22 sexual health clinics in England and Wales. PARTICIPANTS: Participants were patients with a first or repeat episode of anogenital warts who had not been treated in the previous 3 months and had not previously received quadrivalent human papillomavirus vaccine. INTERVENTIONS: Participants were randomised to 5% imiquimod cream (Aldara®; Meda Pharmaceuticals, Takeley, UK) for up to 16 weeks or 0.15% podophyllotoxin cream (Warticon®; GlaxoSmithKlein plc, Brentford, UK) for 4 weeks, which was extended to up to 16 weeks if warts persisted. Participants were simultaneously randomised to quadrivalent human papillomavirus vaccine (Gardasil) or saline control at 0, 8 and 24 weeks. Cryotherapy was permitted after week 4 at the discretion of the investigator. MAIN OUTCOME MEASURES: The main outcome measures were a combined primary outcome of wart clearance at week 16 and remaining wart free at week 48. Efficacy analysis was by logistic regression with multiple imputation for missing follow-up values; economic evaluation considered the costs per quality-adjusted life-year. RESULTS: A total of 503 participants were enrolled and attended at least one follow-up visit. The mean age was 31 years, 66% of participants were male (24% of males were men who have sex with men), 50% had a previous history of warts and 2% were living with human immunodeficiency virus. For the primary outcome, the adjusted odds ratio for imiquimod cream versus podophyllotoxin cream was 0.81 (95% confidence interval 0.54 to 1.23), and for quadrivalent human papillomavirus vaccine versus placebo, the adjusted odds ratio was 1.46 (95% confidence interval 0.97 to 2.20). For the components of the primary outcome, the adjusted odds ratio for wart free at week 16 for imiquimod versus podophyllotoxin was 0.77 (95% confidence interval 0.52 to 1.14) and for quadrivalent human papillomavirus vaccine versus placebo was 1.30 (95% confidence interval 0.89 to 1.91). The adjusted odds ratio for remaining wart free at 48 weeks (in those who were wart free at week 16) for imiquimod versus podophyllotoxin was 0.98 (95% confidence interval 0.54 to 1.78) and for quadrivalent human papillomavirus vaccine versus placebo was 1.39 (95% confidence interval 0.73 to 2.63). Podophyllotoxin plus quadrivalent human papillomavirus vaccine had inconclusive cost-effectiveness compared with podophyllotoxin alone. LIMITATIONS: Hepatitis A vaccine as control was replaced by a saline placebo in a non-identical syringe, administered by someone outside the research team, for logistical reasons. Sample size was reduced from 1000 to 500 because of slow recruitment and other delays. CONCLUSIONS: A benefit of the vaccine was not demonstrated in this trial. The odds of clearance at week 16 and remaining clear at week 48 were 46% higher with vaccine, and consistent effects were seen for both wart clearance and recurrence separately, but these differences were not statistically significant. Imiquimod and podophyllotoxin creams had similar efficacy for wart clearance, but with a wide confidence interval. The trial results do not support earlier evidence of a lower recurrence with use of imiquimod than with use of podophyllotoxin. Podophyllotoxin without quadrivalent human papillomavirus vaccine is the most cost-effective strategy at the current vaccine list price. A further larger trial is needed to definitively investigate the effect of the vaccine; studies of the immune response in vaccine recipients are needed to investigate the mechanism of action. TRIAL REGISTRATION: Current Controlled Trials. Current Controlled Trials ISRCTN32729817 and EudraCT 2013-002951-14. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 47. See the NIHR Journals Library website for further project information.


The HIPvac [Human papillomavirus infection: a randomised controlled trial of Imiquimod cream (5%) versus Podophyllotoxin cream (0.15%), in combination with quadrivalent human papillomavirus or control vaccination in the treatment and prevention of recurrence of anogenital warts] trial compared two commonly used creams to treat genital warts: 0.15% podophyllotoxin cream (Warticon®; GlaxoSmithKlein plc, Brentford, UK) and 5% imiquimod cream (Aldara®; Meda Pharmaceuticals, Takeley, UK). It also investigated whether or not a vaccine used to prevent human papillomavirus infection, quadrivalent human papillomavirus vaccine (Gardasil®, Merck Sharp & Dohme Corp., Merck & Co., Inc., Whitehouse Station, NJ, USA), could help treat warts or prevent them from coming back in patients whose warts had been cleared. The HIPvac trial was a randomised controlled trial involving 503 patients with warts attending sexual health clinics in England and Wales. The creams and the vaccine were well tolerated; there was some soreness where the cream was applied, but no unexpected side effects. When deciding which treatment was better, we looked at whether or not the warts had cleared by 16 weeks after starting treatment and, if cleared, whether or not they returned by 48 weeks. We compared the creams against each other, and the addition of vaccine against no vaccine (a placebo injection). Patients were allowed to have cryotherapy (freezing treatment) as well, if the investigator advised this. We also calculated the value for money of each type of treatment. The two creams were very similar in how well they worked to clear the warts. One difference was that podophyllotoxin cream worked slightly quicker. The number of patients given cryotherapy was about the same for both types of cream. We had expected that recurrence of warts after treatment with imiquimod cream might be less than after treatment with podophyllotoxin cream, but, in fact, the two creams were similar. Quadrivalent human papillomavirus vaccine did not improve clearance of warts or reduce the chance of recurrence, but the result remains inconclusive. If we had been able to recuit 1000 participants as originally planned, we might have been able to be more certain about whether there was any benefit of vaccination. Further research would be needed to investigate any possible effect. The two creams offered similar value for money in treating warts. Giving patients the vaccine in addition to the cream is not good value for money at its current list price, given the uncertainty about the benefit it offers.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Condiloma Acuminado/tratamento farmacológico , Quimioterapia Combinada , Imiquimode/administração & dosagem , Ceratolíticos/administração & dosagem , Vacinas contra Papillomavirus , Podofilotoxina/administração & dosagem , Adulto , Inglaterra , Feminino , Homossexualidade Masculina , Humanos , Masculino , Prevenção Secundária , Resultado do Tratamento , País de Gales , Adulto Jovem
14.
Nat Commun ; 11(1): 3677, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32699279

RESUMO

Through the formation of concentration gradients, morphogens drive graded responses to extracellular signals, thereby fine-tuning cell behaviors in complex tissues. Here we show that the chemokine CXCL13 forms both soluble and immobilized gradients. Specifically, CXCL13+ follicular reticular cells form a small-world network of guidance structures, with computer simulations and optimization analysis predicting that immobilized gradients created by this network promote B cell trafficking. Consistent with this prediction, imaging analysis show that CXCL13 binds to extracellular matrix components in situ, constraining its diffusion. CXCL13 solubilization requires the protease cathepsin B that cleaves CXCL13 into a stable product. Mice lacking cathepsin B display aberrant follicular architecture, a phenotype associated with effective B cell homing to but not within lymph nodes. Our data thus suggest that reticular cells of the B cell zone generate microenvironments that shape both immobilized and soluble CXCL13 gradients.


Assuntos
Linfócitos B/imunologia , Microambiente Celular/imunologia , Quimiocina CXCL13/metabolismo , Células Dendríticas Foliculares/imunologia , Imunidade Adaptativa , Animais , Linfócitos B/citologia , Linfócitos B/metabolismo , Catepsina B/genética , Catepsina B/metabolismo , Linhagem Celular , Quimiocina CXCL13/imunologia , Simulação por Computador , Células Dendríticas Foliculares/citologia , Células Dendríticas Foliculares/metabolismo , Matriz Extracelular/metabolismo , Humanos , Camundongos , Camundongos Knockout , Microscopia de Fluorescência , Modelos Biológicos , Tonsila Palatina/citologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Células Estromais/imunologia , Células Estromais/metabolismo
16.
Antivir Ther ; 25(1): 55-59, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32202510

RESUMO

BACKGROUND: Protease inhibitors (PI) have relatively low penetration into the genital tract, raising concerns about the potential for genital HIV RNA shedding in patients taking PI-based regimens, particularly PI monotherapy (PI-mono). METHODS: We measured HIV RNA and PI drug concentrations in samples of semen, cervico-vaginal and rectal mucosa secretions, and plasma in patients after 48-96 weeks on PI-mono or standard triple therapy. RESULTS: A total of 85 participants were recruited. Of the 43 participants on PI-mono (70% on darunavir [DRV]/ritonavir [r]), 3 had detectable virus in semen or vaginal secretions (all below quantification limit), and none in rectal mucosa or plasma. Among those taking triple therapy, five had detectable virus in semen or vaginal secretions (HIV RNA >50 copies/ml in one), none in rectal mucosa and one in plasma. The median (IQR) concentration of DRV and atazanavir in semen (659.7 [339-1,089] and 128.8 [63-368] ng/ml, respectively) and cervico-vaginal samples (2,768 [312-7,879] and 1,836 [359-3,314] ng/ml, respectively) exceeded their protein adjusted median inhibition concentration (MIC50). DRV concentration in rectal secretions showed higher variability compared with concentration in the other sites, with particularly high rectal secretion/blood ratios (median 8.4, IQR 2.6-68.7:1). CONCLUSIONS: We found no substantive evidence of HIV shedding in patients taking PI-mono, suggesting that PIs provide adequate control of virus in the genital compartment and are unlikely to lead to ongoing sexual transmission.


Assuntos
Terapia Antirretroviral de Alta Atividade , Genitália/virologia , Infecções por HIV/virologia , Inibidores da Protease de HIV/uso terapêutico , RNA Viral/metabolismo , Ritonavir/uso terapêutico , Eliminação de Partículas Virais/efeitos dos fármacos , Estudos Transversais , Feminino , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Ritonavir/administração & dosagem , Sêmen/virologia , Vagina/virologia
17.
Papillomavirus Res ; 8: 100174, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31252073

RESUMO

Persons with HIV are at increased risk of HPV infection, HPV disease, and HPV-related cancers compared to HIV negative persons. In persons with HIV, immune responses to vaccination are often sub-optimal, and while these improve with ART, they often remain lower and decline more rapidly than in HIV-negative individuals. Although the evidence base to support the immunogenicity of HPV vaccines in HIV + ve persons is reasonable, the evidence base to support the efficacy of HPV vaccines in HIV + ve individuals is inconsistent. There is one study in HIV + ve men who have sex with men (MSM) which showed no effect, and two other studies, one in HIV + ve women and one in HIV + ve adolescents that showed reduced effectiveness. All these effectiveness studies used Gardasil 4 (G4). Two studies in HIV + ve persons have shown superior immunogenicity of Cervarix (which uses a TLR4 agonist adjuvant) compared to G4. Studies of Hepatitis B vaccines in HIV + ve persons have shown that either (i) increased number of doses (ii) increased vaccine dose, or (iii) TLR agonist adjuvanted vaccines, all produce increased immunogenicity compared to standard vaccine regimes. Therefore, questions remain as to optimal HPV vaccine regimes in HIV and further clinical trials with different HPV vaccine regimes are needed.


Assuntos
Coinfecção , Infecções por HIV/epidemiologia , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/imunologia , Vacinação , Feminino , Infecções por HIV/imunologia , Infecções por HIV/virologia , Humanos , Imunogenicidade da Vacina , Avaliação de Resultados em Cuidados de Saúde , Vacinas contra Papillomavirus/administração & dosagem , Vacinas contra Papillomavirus/efeitos adversos
18.
Sex Transm Dis ; 46(5): e53-e56, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30444798

RESUMO

Vaccines against hepatitis B virus confer effective protection. Enzyme-linked immunosorbent assay was developed to test for specific antibodies in female genital tract secretions. Anti-hepatitis B IgG and IgA were detected in the cervicovaginal secretions of women after hepatitis B vaccination, indicating a potential genital tract role for neutralizing antibodies against sexually transmitted hepatitis B virus.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vacinas contra Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Hepatite B/prevenção & controle , Vacinação , Adulto , Formação de Anticorpos , Feminino , Genitália Feminina/imunologia , Genitália Feminina/virologia , Hepatite B/imunologia , Hepatite B/virologia , Humanos , Hímen/imunologia , Hímen/virologia , Imunoglobulina A/imunologia , Imunoglobulina G/imunologia , Adulto Jovem
19.
BMC Med Res Methodol ; 18(1): 125, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30400777

RESUMO

BACKGROUND: Anogenital warts are the second most common sexually transmitted infection diagnosed in sexual health services in England. About 90% of genital warts are caused by human papillomavirus (HPV) types 6 or 11, and half of episodes diagnosed are recurrences. The best and most cost-effective treatment for patients with anogenital warts is unknown. The commonly used treatments are self-administered topical agents, podophyllotoxin (0.15% cream) or imiquimod (5% cream), or cryotherapy with liquid nitrogen. Quadrivalent HPV (qHPV) vaccination is effective in preventing infection, and disease, but whether it has any therapeutic effect is not known. METHODS AND DESIGN: To investigate the efficacy of clearance and prevention of recurrence of external anogenital warts by topical treatments, podophyllotoxin 0.15% cream or imiquimod 5% cream, in combination with a three-dose regimen of qHPV or control vaccination. 500 adult patients presenting with external anogenital warts with either a first or subsequent episode of anogenital warts will be entered into this randomised, controlled partially blinded 2 × 2 factorial trial. DISCUSSION: The trial is expected to provide the first high-quality evidence of the comparative efficacy and cost-effectiveness of the two topical treatments in current use, as well as investigate the potential benefit of HPV vaccination, in the management of anogenital warts. TRIAL REGISTRATION: The trial was registered prior to starting recruitment under the following reference numbers: International Standard Randomized Controlled Trial Number (ISRCTN) Registry - ISRCTN32729817 (registered 25 July 2014); European Union Clinical Trials Register (EudraCT) - 2013-002951-14 (registered 26 June 2013).


Assuntos
Imiquimode/uso terapêutico , Papillomaviridae/efeitos dos fármacos , Infecções por Papillomavirus/tratamento farmacológico , Vacinas contra Papillomavirus/uso terapêutico , Podofilotoxina/uso terapêutico , Adulto , Quimioterapia Combinada , Feminino , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Humanos , Masculino , Papillomaviridae/imunologia , Papillomaviridae/fisiologia , Infecções por Papillomavirus/prevenção & controle , Infecções por Papillomavirus/virologia , Vacinas contra Papillomavirus/imunologia , Recidiva , Resultado do Tratamento , Vacinação
20.
PLoS Negl Trop Dis ; 11(5): e0005527, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28498840

RESUMO

BACKGROUND: Visceral leishmaniasis (VL or kala azar) is the most serious form of human leishmaniasis, responsible for over 20,000 deaths annually, and post kala azar dermal leishmaniasis (PKDL) is a stigmatizing skin condition that often occurs in patients after successful treatment for VL. Lack of effective or appropriately targeted cell mediated immunity, including CD8+ T cell responses, underlies the progression of VL and progression to PKDL, and can limit the therapeutic efficacy of anti-leishmanial drugs. Hence, in addition to the need for prophylactic vaccines against leishmaniasis, the development of therapeutic vaccines for use alone or in combined immuno-chemotherapy has been identified as an unmet clinical need. Here, we report the first clinical trial of a third-generation leishmaniasis vaccine, developed intentionally to induce Leishmania-specific CD8+ T cells. METHODS: We conducted a first-in-human dose escalation Phase I trial in 20 healthy volunteers to assess the safety, tolerability and immunogenicity of a prime-only adenoviral vaccine for human VL and PKDL. ChAd63-KH is a replication defective simian adenovirus expressing a novel synthetic gene (KH) encoding two Leishmania proteins KMP-11 and HASPB. Uniquely, the latter was engineered to reflect repeat domain polymorphisms and arrangements identified from clinical isolates. We monitored innate immune responses by whole blood RNA-Seq and antigen specific CD8+ T cell responses by IFNγ ELISPOT and intracellular flow cytometry. FINDINGS: ChAd63-KH was safe at intramuscular doses of 1x1010 and 7.5x1010 vp. Whole blood transcriptomic profiling indicated that ChAd63-KH induced innate immune responses characterized by an interferon signature and the presence of activated dendritic cells. Broad and quantitatively robust CD8+ T cell responses were induced by vaccination in 100% (20/20) of vaccinated subjects. CONCLUSION: The results of this study support the further development of ChAd63-KH as a novel third generation vaccine for VL and PKDL. TRIAL REGISTRATION: This clinical trial (LEISH1) was registered at EudraCT (2012-005596-14) and ISRCTN (07766359).


Assuntos
Vacinas contra Leishmaniose/imunologia , Vacinas contra Leishmaniose/isolamento & purificação , Leishmaniose Cutânea/prevenção & controle , Leishmaniose Cutânea/terapia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/terapia , Adenovirus dos Símios/genética , Adolescente , Adulto , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Linfócitos T CD8-Positivos/imunologia , Portadores de Fármacos , ELISPOT , Feminino , Citometria de Fluxo , Voluntários Saudáveis , Humanos , Injeções Intramusculares , Interferon gama/metabolismo , Leishmania/genética , Leishmania/imunologia , Vacinas contra Leishmaniose/administração & dosagem , Vacinas contra Leishmaniose/efeitos adversos , Masculino , Pessoa de Meia-Idade , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/efeitos adversos , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/isolamento & purificação , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA