Biomedical subjects

Sheena McCormack

Publications and source records attributed to Sheena McCormack.

6 recordsLinked to original sources

PubMed2005

A randomized controlled safety and acceptability trial of dextrin sulphate vaginal microbicide gel in sexually active women in Uganda.

OBJECTIVE: To assess the safety of dextrin sulphate (DS) gel compared to placebo gel in terms of local and systemic adverse events, and to determine the acceptability of dextrin sulphate gel. DESIGN: A 4-week randomized trial of DS intra-vaginal gel, partially blinded, with placebo and observation control arms. Participants were randomized to use DS gel twice daily, placebo gel twice daily, DS gel pre-sex, or into an observation only arm. METHODS: Sexually active women were recruited from post natal and HIV clinics at Nsambya Hospital, Kampala, Uganda. Screening, enrollment and follow-up visits took place every 1 or 2 weeks over an 8-week period and consisted of questionnaire interviews, colposcopy examinations, sexually transmitted infection screen and routine laboratory testing. RESULTS: Out of a total of 172 women screened, 109 were randomized to use DS gel twice daily (65 women), placebo gel twice daily (15 women), DS gel pre-sex (nine women) or into an observation only arm (20 women). Two individuals had abnormal colposcopy findings in the DS twice daily gel use arm. Vaginal bleeding was reported as frequently by participants in the active gel arm as by participants in the placebo and observation only arms. No clinically significant difference was observed between arms in terms of vaginal flora, Candida, haemoglobin, white cell count, platelets, thrombin time, activated partial thromboplastin time, creatinine and aspartate aminotransferase results after 4 weeks of gel use. DS gel appeared to be acceptable to over 95% of the users. CONCLUSIONS: Results show a satisfactory safety and acceptability profile of dextrin sulphate gel.

Administration, Intravaginal↗

PubMed2005

Phase I clinical trial safety of DNA- and modified virus Ankara-vectored human immunodeficiency virus type 1 (HIV-1) vaccines administered alone and in a prime-boost regime to healthy HIV-1-uninfected volunteers.

DNA- and modified virus Ankara (MVA)-vectored candidate vaccines expressing human immunodeficiency virus type 1 (HIV-1) clade A-derived p24/p17 gag fused to a string of HLA class I epitopes, called HIVA, were tested in phase I trials in healthy, HIV-1/2-uninfected adults in Oxford, United Kingdom. Eighteen volunteers were vaccinated with pTHr.HIVA DNA (IAVI-001) alone, 8 volunteers received MVA.HIVA (IAVI-003) alone and 9 volunteers from study IAVI-001 were boosted with MVA.HIVA 9-14 months after DNA priming (IAVI-005). Immunogenicity results observed in these trials was published previously [Mwau M, Cebere I, Sutton J, Chikoti P, Winstone N, Wee EG-T, et al. An HIV-1 clade A vaccine in clinical trials: stimulation of HIV-specific T cell responses by DNA and recombinant modified vaccinia virus Ankara (MVA) vaccines in humans. J Gen Virol 2004;85:911-9]. Here, we report on the safety of the two vaccines and the vaccine regimes. Overall, both candidate vaccines were safe and well tolerated. There were no reported vaccine-related adverse events over the 6-month period of the study and up to 2 years after the last vaccination. There were no moderate or severe local symptoms recorded after the pTHr.HIVA DNA intramuscular administration. Almost all participants experienced local reactogenicity events such as redness and induration after MVA.HIVA intradermal injection. Thus, the results from these initial small phase I trials administering the pTHr.HIVA DNA and MVA.HIVA vaccines either alone or in a prime-boost regime to healthy HIV-1/2-negative adults indicated that the vaccines were safe and warranted further testing of this approach in larger phase I/II studies.

AIDS Vaccines↗

PubMed2005

A dose-ranging phase I study of dextrin sulphate, a vaginal microbicide, in HIV-negative and HIV-positive female volunteers.

DESIGN: This phase I dose-ranging study of 2 weeks of twice-daily dextrin sulphate (DS), a sulphated polymer with in vitro activity against HIV, was designed in 2 parts. Part A was a randomized, placebo-controlled, double-blind, 3-arm trial (DS4%, DS1%, placebo) in HIV-negative women. In part B, HIV-positive women received DS4% and HIV-negative women were randomized to DS4% or no gel. RESULTS: One hundred women were enrolled from 2 sites (London and Antwerp): DS4% (n = 50, 20 of whom were HIV-positive), DS1% (n = 20), placebo (n = 10) and no gel (n = 20). There were no withdrawals related to adverse events and no cases of epithelial disruption. Spotting was reported by 24 women and numbers were significantly higher in all the gel groups (23 of 80), including placebo, compared with no gel (one of 20) (Fisher exact test P = 0.037). There was no evidence of a dose effect. Safety tests showed no evidence of systemic absorption. CONCLUSION: Although there was no clear explanation for the spotting, DS4% was well tolerated. It was decided to proceed with DS4% in an expanded safety study in Africa but to restrict entry to low-risk HIV-negative women, include a no-gel group, and monitor intermenstrual bleeding closely.

Administration, Intravaginal↗

PubMed2004

Long-term persistence of HIV-1 vaccine-induced CD4+CD45RA-CD62L-CCR7- memory T-helper cells.

OBJECTIVE: To determine in chimpanzees if candidate HIV-1 subunit protein vaccines were capable of eliciting long-lasting T-cell memory responses in the absence of viral infection, and to determine the specific characteristics of these responses. DESIGN: A longitudinal study of cell-mediated immune responses induced in three chimpanzees following immunization with subunit envelope glycoproteins of either HIV-1 or herpes simplex virus (HSV)-2. Following these pre-clinical observations, four human volunteers who had been immunized 7 years previously with the same HIV-1 vaccine candidate donated blood for assessment of immune responses. METHODS: Responses were monitored by protein and peptide based ELISpot assays, lymphocyte proliferation, and intracellular cytokine staining. Humoral responses were assessed by enzyme-linked immunosorbent assay and virus neutralization assays. RESULTS: Although antigen (Ag)-specific CD4 T-cell responses persisted for at least 5 years in chimpanzees, CD8 T-cell responses were discordant and declined within 2 years. Detailed cellular analyses revealed that strong Th1 in addition to Th2 type responses were induced by AS2/gp120 and persisted, whereas CD8 T-cell memory declined in peripheral blood. The specificity of both Th and cytotoxic T-lymphocyte responses revealed that the majority of responses were directed to conserved epitopes. The remarkable persistence of Ag-specific CD4 T-cell memory was characterized as a population of the CD45RA-CD62L-CCR7- "effector phenotype" producing the cytokines IFNgamma, IL-2 and IL-4 upon epitope-specific recognition. Importantly, results in chimpanzees were confirmed in peripheral blood of one of four human volunteers studied more than 7 years after immunization. CONCLUSION: These studies demonstrate that epitope-specific Th1 and Th2 cytokine-dependent Th responses can be induced and maintained for longer than 5 years by immunization with subunit proteins of HIV-1.

AIDS Vaccines↗

PubMed2002

Dextrin sulfate as a vaginal microbicide: randomized, double-blind, placebo-controlled trial including healthy female volunteers and their male partners.

This randomized, placebo-controlled trial assessed the safety and acceptability of vaginally administered 0.125% dextrin sulfate (DS) gel in sexually active women and their male partners. A single 2-mL dose of study gel was self-administered every night over two 14-day periods separated by a 7-day interval, during which menses was expected to occur. Up to two supplementary doses per 24 hours were provided for use before sexual intercourse. Semistructured interview, colposcopy, and laboratory safety studies were used to assess adverse events. Male partners who agreed to participate in a substudy were exposed to gel through sexual intercourse during the second 14-day exposure period. Seventy-three women (36 DS recipients and 37 placebo recipients) used at least one application of gel, of whom 66 (33 DS recipients and 33 placebo recipients) completed follow-up. Eleven women (5 DS recipients and 6 placebo recipients) reported intermenstrual bleeding during gel use, which in most cases was light and resolved within 24 hours. Ten male partners (4 with DS exposure and 6 with placebo exposure) were enrolled in the study and all completed follow-up. There was no evidence of systemic toxicity or genital epithelial disruption attributable to DS gel.

Adult↗

PubMed2002

Vaginal microbicides.

The focus of this review will be to highlight articles from 2000 and up to August 2001 that demonstrate the challenges in the evaluation of candidate microbicides, and the ways in which investigators have approached these challenges.

Administration, Intravaginal↗