Effectiveness of cellulose sulfate vaginal gel for the prevention of HIV infection: results of a Phase III trial in Nigeria.
BACKGROUND
This trial evaluated the safety and effectiveness of 6% cellulose sulfate vaginal gel in preventing male-to-female vaginal transmission of HIV, gonorrhea and chlamydial infection.


METHODS
This Phase III, double-blind, randomized, placebo-controlled trial was conducted between November 2004 and March 2007 in Lagos and Port Harcourt, Nigeria. We enrolled 1644 HIV-antibody negative women at high risk of HIV acquisition. Study participants were randomized 1:1 to cellulose sulfate or placebo and asked to use gel plus a condom for each act of vaginal intercourse over one year of follow-up. The participants were evaluated monthly for HIV, gonorrhea and chlamydial infection, and for adverse events.


RESULTS
The trial was stopped prematurely after the data safety monitoring board of a parallel trial concluded that cellulose sulfate might be increasing the risk of HIV. In contrast, we observed fewer infections in the active arm (10) than on placebo (13), a difference that was nonetheless not statistically significant (HR = 0.8, 95% CI 0.3-1.8; p = 0.56). Rates of gonorrhea and chlamydial infection were lower in the CS group but the difference was likewise not statistically significant (HR = 0.8, 95% CI 0.5-1.1; p = 0.19 for the combined STI outcome). Rates of adverse events were similar across study arms. No serious adverse events related to cellulose sulfate use were reported.


CONCLUSIONS
Cellulose sulfate gel appeared to be safe in the evaluated study population but we found insufficient evidence that it prevented male-to-female vaginal transmission of HIV, gonorrhea or chlamydial infection. The early closure of the trial compromised the ability to draw definitive conclusions about the effectiveness of cellulose sulfate against HIV.


BACKGROUND
ClinicalTrials.gov NCT00120770.
Halpern
Vera
V
Family Health International, Research Triangle Park, North Carolina, United States of America. vhalpern@fhi.org
Ogunsola
Folasade
F
Obunge
Orikomaba
O
Wang
Chin-Hua
CH
Onyejepu
Nneka
N
Oduyebo
Oyinola
O
Taylor
Doug
D
McNeil
Linda
L
Mehta
Neha
N
Umo-Otong
John
J
Otusanya
Sakiru
S
Crucitti
Tania
T
Abdellati
Said
S
D000293:Adolescent; D000328:Adult; D002482:Cellulose / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D002690:Chlamydia Infections / Q000517:prevention & control / Q000635:transmission; D003075:Coitus; D017280:Condoms; D004311:Double-Blind Method; D005260:Female; D006069:Gonorrhea / Q000517:prevention & control / Q000635:transmission; D015658:HIV Infections / Q000517:prevention & control* / Q000635:transmission; D006801:Humans; D008297:Male; D009549:Nigeria; D012449:Safety; D016896:Treatment Outcome; D014622:Vaginal Creams, Foams, and Jellies; D055815:Young Adult
D014622:Vaginal Creams, Foams, and Jellies; D002482:Cellulose; C020254:cellulose sulfate