Formestane cluster snares six more trainers

An additional six Victorian horse trainers have been charged over the presence of prohibited substances linked to formestane, as the saga over the breast cancer drug widens.

There have now been 13 different stables caught up in positive formestane tests between February 2023 and November 2025, despite Racing Victoria commissioning a global research project to determine whether thresholds or treatment rules need to be changed.

The latest trainers charged were Matthew Brown, Adam Chambers, Nathan Dunn, Lee and Shannon Hope, Lloyd Kennewell and Paul Preusker, and relate to horses that raced between April and November 2025.

All were found to have traces of formestane, 4-hydroxytestosterone and 6a-hydroxyandrostenedione in their systems.

The trainers have been charged under the presentation rule, which applies when a horse arrives at a racetrack with a prohibited substance in its system, regardless of how it entered the horse’s body.

Formestane is an anti-estrogenic aromatase inhibitor, while 4-hydroxytestosterone and 6a-hydroxyandrostenedione are classified as anabolic androgenic steroids.

Under the rules of racing, any horse returning a positive test for anabolic steroids must be suspended from racing for 12 months. All six horses involved in the latest cases were automatically stood down from the date their samples were collected.

The impacted horses are Iluvcoffee (Lee and Shannon Hope), Inthelapofthegods (Nathan Dunn), Rip ‘N’ Rip (Matthew Brown), Major Share (Adam Chambers), Nursery Chime (Lloyd Kennewell) and Chairman (Paul Preusker).

In an extensive release, RV said there have been no confirmed cases in Victorian thoroughbreds since November 2025 and no further investigations are currently underway.

Six previous cases involving other Victorian trainers have already been finalised in the VRT, with trainers pleading guilty to presentation charges and receiving fines. RV said those decisions now provide a penalty precedent for outstanding matters.

Racing Analytical Services Limited (RASL), Victoria’s accredited racing laboratory, has screened for the compounds since 2017 without recording a single detection during its first six years of testing, but it has since detected the substances in 24 samples across thoroughbred and harness racing in Victoria, South Australia, Tasmania and Chile.

The spike in cases has caught industry attention but RASL maintains there has been no change to its testing equipment, methodology or sensitivity that could explain the increase.

The uncertainty surrounding the substances has prompted RV to commission a global research project.

Should future research show the substances can occur naturally at low levels, rule changes and threshold limits may eventually be considered. However, RV has made clear any such changes would be unlikely to affect historical cases, which are assessed under the rules in force at the time.

Brown, Chambers, Kennewell and Preusker, whose positive samples were collected after the July 2025 removal of AR240(2) from the Serious Offence List will have their charges heard by RV stewards in the next four to six weeks.

Due to the earlier timing of their swabs, Dunn and the Hopes have had their charges referred to the VRT, with hearings on a date to be fixed.