Study shows Avanti breaks more than latex condoms
Study shows Avanti breaks more than latex condoms
Despite failures, pregnancy rates are favorable
A large clinical efficacy study of the first approved polyurethane condom found that Avanti failed more than the latex control condom, but showed similar protection against pregnancy. Faced with those seemingly conflicting results, the Food and Drug Administration must now decide what type of labeling it will allow on the polyurethane condom.
Although the study was completed in March, the National Institute of Child Health and Human Development (NICHD) has not publicized the results. The contractor for the study, the California Family Planning Council in Los Angeles, has submitted the study for publication in a peer-reviewed journal and is reluctant to discuss the findings until they are published, says Ron Frazieres, MSPH, director of research for the council.
NICHD officials tell AIDS Alert the study met its objective, but would not speculate what it would mean in terms of FDA action.
"Albeit the slippage and breakage rates were higher in the polyurethane condom, there were no differences in contraceptive efficacy between the Avanti condom and a standard latex condom," says Gabriel Bialy, MD, deputy director of the contraceptive development branch at the National Institute of Child Health and Human Development in Bethesda, MD.
Ever since it cleared Avanti for marketing in 1991, the FDA has been concerned over possible excessive breakage of the polyurethane condom, which is about half as thick as the average latex condom. Last year, Avanti’s manufacturer, London International Group, PLC, based in London, replaced the originally approved condom with a thicker version after NICHD refused to include it in a contraceptive efficacy trial because of unacceptably high breakage rates. The thicker condom was used in this study.1
Approximately 5% of Avanti condoms in the study failed during intercourse (broke or slipped off), compared to less than 1% of latex condoms. Similarly, nearly 4% of Avanti condoms broke or slipped off during removal compared to 1% for latex.
London International told AIDS Alert earlier this year that it had replaced Avanti condoms on the market with the thicker version. However, labeling for the condom remains the same, stating that the risk of pregnancy and sexually transmitted diseases for the condom is not known but is under study.
"NIH has shared the results of the study with us, and both NIH and we are currently looking at the study results and evaluating them to try to see what they mean," says FDA spokeswoman Sharon Schneider.
Regardless of what the FDA concludes, it is up to the company to broaden or change the labeling for Avanti through a supplement to its application, she noted.
The company is pleased with the study results and will be submitting a label application seeking broader claims, says William Potter, PhD, director of science for London International.
"Our initial take is we are very pleased with the outcome because it has shown that the contraceptive efficacy of Avanti is equal to the latex condom that was used as a control," he reports. "In light of the report, we are revisiting the claims and will be making a revised submission to the FDA very shortly." Avanti, which has been sold in the United States since 1996, has been approved in Europe and will be made available in the United Kingdom in September, he adds.
Commenting on the breakage rates, Potter says Avanti is in line with published breakage rates for latex condoms, which range for this study population from 1.7% to 6.7%. "For the first result on a new product, that is a pretty good solid result," he notes.
The differences in the rates were highly significant, the researchers note, but Bialy would not speculate what they mean in terms of STD protection.
"The pregnancy window is an entirely different window than the infectivity window, and thus we have no information that if one condom breaks twice as much as another, whether that means the potential for infection is twice as high," he says.
Although the pregnancy rate for Avanti was comparable to latex condoms, the researchers note that the rate could have been compromised by more couples dropping out of the study because of problems with Avanti than for those using latex. Of the 61 couples assigned to Avanti who withdrew within 60 days of enrollment, 33% had reported one or more condom failures. In contrast, only 36 couples assigned to the latex condoms dropped out within 60 days, and only 3% had reported condom failure. "This difference in patterns of study discontinuation could obscure a true difference between the pregnancy rates of the two studies," they note.
Other findings of the study include:
• Couples reported having more difficulty putting on Avanti condoms than latex condoms problems with donning were reported in 25% of Avanti condoms, compared to 7% for latex. The difficulty could be attributed to using a new product, and the company is using user feedback to make future improvements, Potter says.
• More than 70% of male and female participants who used Avanti reported that the odor was more pleasant than that of latex condoms.
• Study participants who used latex condoms were more likely to recommend their condom than those who used Avanti. For males, 83% recommended latex, compared to 62% for Avanti. For females, 85% recommended latex, compared to 67% who used Avanti.
• Although Avanti is nearly half as thick as latex condoms, only 42% of male partners in the study judged it to be more sensitive than the latex condom.
• Couples who used Avanti condoms reported a lower frequency of penile constriction (2.2%) compared to those who used latex condoms (6%).
Reference
1. Study of the efficacy, acceptability and safety of a non-latex (polyurethane) male condom. No1-HD-1-3109. n
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