A short-term evaluation of semen and accessory sex gland function in phase III trial subjects receiving intravasal contraceptive RISUG

Abstract 

Following the intravasal injection of a new male contraceptive RISUG (reversible inhibition of sperm under guidance) in volunteers, routine semen analysis, semen biochemistry and germ cell morphology were evaluated in comparison with the corresponding preinjection samples for a maximum period of 6 months. Sperm counts in all 25 subjects before injection varied from 45 to 120 × 10⁶/ml. Out of 25 subjects, 6 became azoospermic after 1 month, 15 after 2 months, 3 after 3 months and 1 after 4 months of contraceptive injection. The mean volume of the ejaculates was found to be less as compared to preinjection samples. Occasional sperm or sperm heads and immature germ cells were identified in only a few postinjected subjects. However, no pregnancy was reported in these subjects during the study period. Abnormal morphology found in most of the sperm, but not in the accompanying immature germ cells, may be due to a charge-related effect on the former but not on the latter cells. Neutral α-glucosidase, the biochemical marker for epididymis, was estimated to be significantly lower in the seminal plasma of all the postinjected subjects. On the other hand, acid phosphatase activity and fructose levels in the seminal plasma were found to be in the normal range. Based on the above findings, it is concluded that at least for the present study period, RISUG, a new male contraceptive, is effective as a partially occluding agent in the vas deferens.

Keywords: New male contraceptive, RISUG, Semen analysis, Semen biochemistry, Sperm and germ cell morphology