Mystery as five racehorses test positive for breast cancer drug despite all having different trainers and stables

Five Australian trainers are still looking for answers after their horses all tested positive for formestane, a drug used to treat breast cancer.

Racing Victoria stewards launched a 12-month investigation following the discovery, with Melbourne Cup-winning trainer Mark Kavanagh one of the quintet in the line of fire.

Kavanagh famously trained Shocking to victory in the 2009 stop-a-nation race – but his mare Circle of Magic, who finished second in a BM64 at Sandown on March 8 last year, was halted for 12 months after a urine sample showed traces of formestane .

Fellow trainers Julius Sandhu (Alphaville), Symon Wilde (Sirileo Miss), Amy and Ash Yargi (Yulara) and Smiley Chan (Lake Tai) were equally stunned when their horses tested positive for the banned substance.

It is expected that all five trainers will soon be addressed by stewards.

Formestane – which is on the WADA banned list – is best known medically for the treatment of breast cancer, especially in postmenopausal women.

The drug is designed to inhibit the production of estrogen because some breast cancer cells depend on estrogen for their viability.

But according to The ageit also leads to an increase in the body’s production of hormones and testosterone.

While all five trainers immediately saw their horses banned for a year, it took almost six months for Racing Victoria stewards to reveal the details of the positive swab tests to the public.

Both the Kavanagh and Yargi stables pointed to contamination as a potential source of the positive swabs in statements on the issue, but the bans were not lifted.

The Symon Wilde-trained Sirileo Miss won the Group 3 Matron Stakes at Flemington and the Group 2 Sunline Stakes at Moonee Valley before her suspension

Wilde was left thinking about what might have been after the suspension of ‘his best horse’ was confirmed.

Before being withdrawn, Sirileo Miss claimed the Group 3 Matron Stakes at Flemington and the Group 2 Sunline Stakes at Moonee Valley.

He also stated that Sirileo Miss could eventually become a very profitable broodmare, and that retirement was discussed – before ultimately deciding to race her again.

“She has missed 12 months in the prime of her racing life, and that doesn’t seem entirely fair,” Wilde said.

‘It’s been very frustrating. You have a good, healthy horse there.’

And despite many questions about how traces of a breast cancer drug appeared in the urine samples – taken from five different horses, trained by five different stables and raced at five different tracks – it appears the mystery may never be solved.