The drug, originally known as STX64, was designed and chemically synthesised in the Medicinal Chemistry Group of our Department of Pharmacy & Pharmacology.
The drug can be given orally and is termed a ‘first-in-class’ irreversible steroid sulfatase inhibitor. It is designed to block the production of oestrogen, which fuels cancer development in two-thirds of all cases.
The drug has already been in several international clinical trials as a monotherapy, in three hormone-dependent cancer areas and is now also being pursued for breast cancer in combination with an existing well-established clinical therapy - a so-called “aromatase inhibitor”, that blocks the production of oestrogen by a different pathway.
The clinical study is investigating whether adding Irosustat to aromatase inhibitor treatment, thus blocking both pathways at the same time, can further reduce the amount of oestrogen and therefore control the breast cancer better. 27 Postmenopausal women with locally advanced or metastatic breast cancer that is not being controlled by their current aromatase inhibitor treatment will be recruited in this study from 9 UK hospitals. Eligible patients will receive 40mg of Irosustat once daily in addition to the aromatase inhibitor on which they progressed.
The recruitment of the first patient to the new trials in Liverpool in September was highlighted in an article in the Daily Mail at the end of October.
Irosustat and its associated intellectual property formed part of the assets of the Bath-Imperial College spin-out company Sterix Ltd. The company was co-founded by Professor Barry Potter from our Department of Pharmacy & Pharmacology and was acquired by the pharmaceutical company Ipsen in 2004.
Commenting on the developments Professor Potter said: “The most rewarding thing for any Medicinal Chemist and Drug Discovery Group is to see a drug synthesized in the lab overcome the multitude of very difficult hurdles and finally be taken in trials as a pill by sick patients.
Only the tiniest fraction of all such development candidates ever make it this far. This requires great and diverse teamwork and comes at a multi-million pound cost. I am optimistic that our new approach should translate into real clinical benefit”.
In 2011 a paper on the drug was awarded ‘Very Important Paper’ status by the medicinal chemistry journal ChemMedChem, including a special cover feature designed by the research group.