Clinical trials in cancer generally measure the success of a new drug based on whether it increases “overall survival”, in other words whether it keeps patients in the test group alive for longer than a control group. However, this method means researchers and regulators need to wait a long time before they can conclude that a new drug is benefiting patients – generally many months or even years.
As part of a Phase III trial for a new prostate cancer drug called abiraterone acetate, scientists at The Institute of Cancer Research (ICR) and The Royal Marsden along with international collaborators investigated whether the level of Circulating Tumour Cells (CTCs) in patients’ blood was linked to their subsequent survival. CTCs are cancer cells that have broken away from a tumour and entered the blood stream.
Scientists analysed blood from almost 1,000 patients with advanced prostate cancer, measuring the number of CTCs before treatment and then at four, eight and twelve weeks after starting treatment. They also measured levels of lactate dehydrogenase (LDH) using another existing blood test. For men with initially high CTC levels, they found those whose CTC and LDH levels fell after treatment were likely to survive longer, while those whose CTCs and LDH did not fall had poor survival rates. A significant change could be measured within four weeks of treatment.
“A change in CTC and LDH levels in patients’ blood was strongly correlated to the length of time they survived following treatment,” trial lead investigator Professor Johann de Bono from the ICR and The Royal Marsden says. “This result raises the possibility that these blood test could be used in clinical trials of new drugs to determine whether patients are benefiting, at a much earlier stage than would be apparent from overall survival data. This could hugely speed up the process of developing new drugs.”
The study was carried out as part of the Phase III trial for abiraterone acetate, a drug discovered at the ICR in what is now the Cancer Research UK Cancer Therapeutics Unit and first trialed at The Royal Marsden. In updated data presented at the conference, the drug was shown to give an extra 4.6 months of life to men with late-stage “castration resistant” prostate cancer who had stopped responding to chemotherapy*.
The study used Veridex’s CELLSEARCH® CTC test, the only regulatory-cleared in vitro diagnostic test to capture and count CTCs. The CTC test is already being incorporated in other Phase III trials and it is hoped that ultimately the panel may be widely used to measure patients’ prognoses.
The Phase III trial of abiraterone was sponsored by Ortho Biotech Oncology Research & Development, a Unit of Cougar Biotechnology Inc. The work on CTCs was funded by a Medical Research Council Biomarkers Grant, The Prostate Cancer Foundation, Experimental Cancer Medical Centre (ECMC), NIHR Biomedical Research Centre Grants (UK) and Veridex LLC.
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Notes to editors:
Abiraterone acetate is not currently available in the UK.
* The “castration-resistant” form of the disease is prostate cancer that continued to grow while the patient was receiving standard therapy to lower their testosterone levels.
Collaborator Howard Scher from Memorial Sloan Kettering Cancer Center in New York presented the data at the ASCO annual meeting this week.
Abiraterone was discovered at the ICR in research supported by grants from Cancer Research Campaign (now Cancer Research UK), the Medical Research Council (MRC) and BTG International LTD. Subsequent patient trials and further research on abiraterone was supported by Cougar Biotechnology Inc. / Janssen Pharmaceutical Companies, Cancer Research UK, Experimental Cancer Medicine Centre, the MRC, BTG International Ltd, Prostate Cancer Foundation, Prostate Cancer Research Foundation, The Prostate Cancer Charity, the ICR and The Royal Marsden. Cancer Research Technology assigned abiraterone acetate to BTG International Ltd, who in turn licensed it to Ortho Biotech Oncology Research & Development, a unit of Cougar Biotechnology Inc., now a member of the Janssen Pharmaceutical Companies.
The Institute of Cancer Research (ICR)
- The ICR is Europe’s leading cancer research centre.
- The ICR has been ranked the UK’s top academic research centre, based on the results of the Higher Education Funding Council’s Research Assessment Exercise.
- The ICR works closely with partner The Royal Marsden NHS Foundation Trust to ensure patients immediately benefit from new research. Together the two organisations form the largest comprehensive cancer centre in Europe.
- The ICR has charitable status and relies on voluntary income, spending 90 pence in every pound of total income directly on research.
- As a college of the University of London, the ICR also provides postgraduate higher education of international distinction.
- Over its 100-year history, the ICR’s achievements include identifying the potential link between smoking and lung cancer which was subsequently confirmed, discovering that DNA damage is the basic cause of cancer and isolating more cancer-related genes than any other organisation in the world.
- The ICR is home to the world’s leading academic cancer drug development team. Several important anti-cancer drugs used worldwide were synthesised at the ICR and it has discovered an average of two preclinical candidates each year over the past five years.
For more information visit www.icr.ac.uk
The Royal Marsden Hospital
The Royal Marsden was the first hospital in the world dedicated to cancer diagnosis, treatment and research into the causes of cancer. Today, as The Royal Marsden NHS Foundation Trust, together with its academic partner The Institute of Cancer Research, form the largest comprehensive cancer centre in Europe with over 40,000 patients from the UK and abroad seen each year. It is a centre of excellence, and was the only NHS Trust to achieve the highest possible ranking in the Healthcare Commission’s Annual Health Check for four year in a row. Prince William became President of The Royal Marsden in 2007, following a long royal connection with the hospital.