A project to develop sex hormone implants as a possible non-surgical sterilant for puppies and kittens

Dr. Jay Ko is a reproductive endocrinologist and a professor at the University of Illinois, College of Veterinary Medicine.  He founded Epivara Inc., which has invested in developing an injectable sterilant for animals. This research has been supported in part by a grant from the National Science Foundation (SBIR Phase 1). The technology, which was granted a patent in 2021, uses synthetic versions of natural estrogen to target Kisspeptin, a hypothalamic neuron that is essential for reproduction.

In June 2023, Scientific Report published Dr. Ko and his team’s research. The publication shared that a single injection produced permanent infertility in rats, and that a subsequent three-year study in dogs has been promising. These studies also suggest that the approach will only be effective when treating puppies or kittens in the first few weeks of life.

Dr. G. Robert Weedon, a member of the ACC&D Board of Directors, and Dr. Michelle Kutzler, a member of ACC&D Scientific Advisory Board, both also serve on Epivara’s Scientific Advisory Board.

More information is available on the Epivara website and their January 2024 outreach article. The website implies availability of a product and makes claims of efficacy, safety and pricing. At this point these are speculative. In order to become commercially available in the U.S., the product must achieve approval from the U.S. Food & Drug Administration (FDA). This will require a large field study in dogs and cats, as well as extensive studies on safety prior to approval. The timeline for research and development plus regulatory review is multiple years, and will require significant investment.