Abstract
BackgroundOptions for male contraception are limited. The purpose of this study was to use a nonhuman primate model to evaluate Vasalgel™, a high molecular weight polymer being developed as a contraceptive device for men.MethodsSixteen adult male rhesus monkeys received intravas injections of Vasalgel, consisting of 25% styrene maleic acid in dimethyl sulfoxide. After a one-week recovery, males were returned to outdoor group housing, which included at least 3 and up to 9 intact, breeding females with a successful reproductive history.ResultsTreated males have had no conceptions since Vasalgel injections. All males were housed with intact females for at least one breeding season and seven have been almost continually housed with females for 2 years. Complications were minor and included one incident of incorrect placement of Vasalgel into the vas deferens and the development of a sperm granuloma in one animal. Three unilateral vasectomies were performed, one was necessary for incorrect placement of Vasalgel, the other two were elective.ConclusionsIntravas injection of Vasalgel in sexually mature adult male rhesus monkeys was effective in preventing conception in a free-living, group environment. Complications were few and similar to those associated with traditional vasectomy.
Highlights
Après une semaine de récupération, les mâles sont ramenés dans le groupe hébergé en plein air constitué d’au moins 3 et jusqu’à 9 femelles reproductrices normales de fertilité prouvée
That product has been studied in nonhuman primates and found to be an effective contraceptive that could be removed from primates with percussive and vibratory massage, returning fertility [4, 5]
This study evaluates the effectiveness of Vasalgel in adult male rhesus monkeys living in small group housing for at least one breeding season and up to 2 years
Summary
Complications were minor and included one incident of incorrect placement of Vasalgel into the vas deferens and the development of a sperm granuloma in one animal. Options for non-permanent male contraceptives are limited to condoms, with no long-term methods currently available. There have been recent advances in developing potentially reversible contraceptive methods that target the vas deferens. RISUG® (Reversible Inhibition of Sperm Under Guidance) is a styrene maleic anhydride (SMA) product for intra-vas injection that lines the vas, but does not occlude it [2]. That product has been studied in nonhuman primates and found to be an effective contraceptive that could be removed from primates with percussive and vibratory massage, returning fertility [4, 5]. While various formulations of RISUG have been studied in India over several decades, no product has successfully been brought to market as of yet
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