Combining two cancer drugs has seen a potential breakthrough for women with metastatic breast cancer.
In a world first, breast cancer researchers at The Royal Melbourne Hospital and Peter MacCallum Cancer Centre, successfully combined a drug that has shown promise in the treatment of chronic leukaemia with therapy used to treat breast cancer.
The Royal Melbourne Hospital’s and Peter MacCallum Cancer Centre’s medical oncologist, Professor Geoff Lindeman, principal investigator of the study, said the combination of the two drugs has given researchers and patients a boost in tackling metastatic breast cancer. Professor Lindeman is also a researcher at the Walter and Eliza Hall Institute.
“The primary aim of the study was to determine the safety and tolerability of Venetoclax in combination with Tamoxifen,” Professor Lindeman said.
“We tested this combination on the basis of our laboratory findings at the Walter and Eliza Hall Institute. Venetoclax is a drug that switches off BCL-2, a protein that helps keep cancer cells alive. Our findings suggest that adding Venetoclax to conventional hormone therapy might boost responses.
“Although the study was aimed at determining safety and finding the right dose, we found that 75% of the women involved in the study experienced an overall improvement or derived clinical benefit.
“This result has provided a basis for further studies with Venetoclax, where the hope would be to produce deeper and more durable responses for women affected by breast cancer.”
Professor Lindeman added this was the first time Venetoclax has been used on solid tumours.
“Venetoclax is not currently approved in breast cancer and further studies will be required to determine its effectiveness,” Professor Lindeman said.
Venetoclax was developed based on a landmark discovery made in Melbourne during the late 1980s by Walter and Eliza Hall Institute scientists, that the BCL-2 promoted cancer cell survival.
“There were 42 women enrolled in the study, which was conducted at The Royal Melbourne Hospital, Peter MacCallum Cancer Centre and Olivia Newton-John Cancer Centre over the last three years.
“The drug was well tolerated, and the majority received the maximum dose with minimal side effects. We have now established a new benchmark dose for future studies.
“We are excited by the findings and what it could mean for patients with incurable hormone receptor positive breast cancer.”
Patient Julie was diagnosed with stage 4 breast cancer just before her 60th birthday. She enrolled in the study and was given the combined dose of Venetoclax and Tamoxifen.
The 10cm tumour in Julie's breast shrank rapidly in response to the treatment.
“My tumour is undetectable at the moment – the doctors said they couldn’t find it,” Julie said.
“I’m hopeful this research will help other women in future."
The research, published today in the journal Cancer Discovery, was supported by a grant from AbbVie and Roche/Genentech, the National Health and Medical Research Council, Victorian State Government through the Victorian Cancer Agency and Operational Infrastructure Support Program, National Breast Cancer Foundation, Australian Cancer Research Foundation, The Qualtrough Cancer Research Fund and Joan Marshall Breast Cancer Research Fund.
For more information about phase two of the trial, visit The Royal Melbourne Hospital website.
Photo: Professor Geoff Lindeman. Credit: The Walter and Eliza Hall Institute.