A male birth control pill without side effects has passed human trials

Pharmaceutical startup YourChoice Therapeutics is conducting clinical trials of the male contraceptive YCT-529, which seems to have no side effects.

It is noted, that YCT-529 has already undergone clinical trials and proved its safety. The following trials are to be conducted for efficiency. It is expected to enter the market in a few years.

In the first randomized, 16 healthy men aged 32 to 59 years participated in a double-blind, placebo-controlled, single-dose, phase Ia study to evaluate the tolerability and safety of YCT-529. They received a single oral dose of YCT-529, 10 to 180 mg (or placebo) both before and after meals, to assess absorption rates. They were then followed for two weeks. 

The researchers recorded the absence of serious side effects at any dose. Hormonal levels remained stable and libido did not change. There were also no changes in markers of inflammation, mood, or key blood chemistry parameters. This indicates, according to the researchers, that YCT-529 has virtually no harmful side effects compared to female contraceptives. 

According to pharmaceutical data, the drug has a long half-life of —10 days from 51 to 76 hours, which makes this drug active and effective for several days. This also means, that the tablet can be taken every 3 days, instead of daily. It is expected, that in future 28- and 90-day studies, the effect of dosage on sperm count will be studied.

Meanwhile, the news of the innovative drug caused a wave of indignation among women, as female contraceptives still have a large number of serious side effects. Results of the study, conducted in 2023, showed, that female contraceptives, which affect the hormonal system by their principle of action, also affect women’s response to stress, the risk of developing inflammatory processes and related diseases, provoke mood swings, rapid weight loss and gain, and increase the risk of stroke and blood clots.

The authors of the study emphasized, that although hormonal female contraceptives are safely used by more than 300 million women worldwide, their physiological and behavioral effects have not been studied enough. Previously, it has been found, that hormonal contraceptives can increase the risk of chronic inflammation, which in the long term can trigger cancer, cardiovascular disease, autoimmune diseases, and potential mood disorders, including depression. The mechanisms of this relationship remain poorly understood. 

Although YCT-529 is not a hormonal contraceptive, and it has sparked widespread debate about the lack of research on the health effects of these contraceptives on women. Unlike hormonal male contraceptives, which typically reduce testosterone levels and can cause side effects, YCT-529 affects a specific protein — retinoic acid receptor alpha (RARα). This receptor is part of the vitamin A signaling pathway required for spermatogenesis. Blocking this receptor stops spermatogenesis, without affecting sex hormones and broader functions of vitamin A in the body. 

In studies on primates and mice, the drug inhibited sperm production and was completely reversible after treatment was discontinued. Results of the latest study on animals were published in the journal Communications Medicine in May this year.

In mice, oral administration of YCT-529 caused almost complete infertility, but fertility was fully restored within six to twelve weeks after treatment discontinuation. In Javanese macaques, the sperm count decreased sharply within two to five weeks and returned to normal within about three months. Currently YCT-529 is the most promising male contraceptive drug that may soon reduce the number of cases of negative side effects in both men and women. 

The results of the study were published in the journal Communications Medicine

Source: Business Wire; NewAtlas