No entries have been received for the new open category at the Swimming World Cup in Berlin this weekend, World Aquatics said on Tuesday.
The governing body introduced the category after voting last year to ban male-to-female transgender athletes from competing in women's elite races.
A statement from the governing body, formerly known as FINA, read: "World Aquatics can confirm that no entries have been received for the open category events.
"Distances in various events had been made available for the open category, introduced on a pilot basis following the adoption of the World Aquatics policy on eligibility for the men's and women's competition categories.
"The World Aquatics Open Category Working Group will continue its work and engagement with the aquatics community on open category events.
"Even if there is no current demand at the elite level, the working group is planning to look at the possibility of including open category races at Masters events in the future."
The Berlin meet, one of three World Cup events this year, will take place from October 6 to 8.
They are all qualifying events for the World Aquatics Championships in Doha next year and the 2024 Paris Olympics.
Open categories had been offered in 50 metres and 100m races across all strokes, with World Aquatics describing it as a "pioneering pilot project".
Transgender participation has become a hot-button issue in recent months as sports try to balance inclusivity with ensuring fair competition.
International governing bodies in cycling and athletics have also banned transgender competitors.
World Athletics announced in March that transgender women would no longer be allowed to compete in female track and field events.
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