The Benilexa IUS consists of a T-shaped frame with a drug reservoir around the vertical stem. The device itself is identical to Levosert, but it is supplied with a single-handed inserter that is reloadable, allowing the IUS be repositioned if loaded incorrectly.
'Unlike other single-handed IUSs [such as Mirena], this levonorgestrel IUS inserter is reloadable, providing reassurance that if loaded incorrectly in the insertion device, we can reposition and reload it,' said Dr Paula Briggs, consultant in sexual and reproductive health at Liverpool Women’s NHS Foundation Trust.
Benilexa is effective for six years as a contraceptive, and has been shown to be effective for three years in treating heavy menstrual bleeding. It should be removed or exchanged after six years, or earlier if heavy or bothersome menstrual bleeding returns.
Phase III trials
Approval of Benilexa is based on outcomes from two phase III trials, one investigating contraceptive efficacy (Access IUS study) and the other evaluating reduction of heavy menstrual bleeding, defined as ≥80ml per menstrual cycle.
The Access IUS study showed that the cumulative pregnancy rate calculated by the Pearl Index in women aged 16 to 35 years using the Levosert levonorgestrel IUS (primary endpoint) was 0.15 (17,125 cycles, 95% CI 0.02–0.55) at the end of year one and 0.18 (66,457 cycles, 95% CI 0.08–0.33) at the end of year six. There were two on-treatment pregnancies in the first year, four further pregnancies in the second year, one additional pregnancy in the third, fourth, and fifth years, and no pregnancy in the sixth year: a total of nine pregnancies out of 66,457 cycles.
In the menstrual blood loss study, levonorgestrel IUS produced a significant reduction in menstrual blood loss within three to six months. The volume of menstrual bleeding decreased by 88% in women with heavy menstrual bleeding after three months of use and an 82% reduction was sustained for the 12-month duration of the study. The effect was maintained during the extension phase of the study, up to 36 months.
The most common adverse events of the levonorgestrel IUS include uterine/vaginal bleeding, oligomenorrhoea, amenorrhoea, and benign ovarian cysts.