Understanding Clinical Trials for Anti-cancer Medicines by Dr Kathleen Thompson
All medicines, for a cancer or anything else, must be tested in clinical trials before doctors can prescribe them.
The first clinical trials test increasing doses of the medicine, in small numbers of people, to determine the highest dose before side-effects become unacceptable. As anybody who has had chemotherapy knows, cancer drugs often have serious side-effects. There may be a thin line between an effective anti-cancer dose, and a harmful dose, and knowledge of where this threshold occurs is important.
Anti-cancer medicines are usually only tested in people with cancer. People in the early trials often have serious progressive cancer, for which there are no other effective treatments. In later studies, when more information is known, people with less advanced cancer can be included.
If possible, clinical trials include a placebo arm, where some participants receive the new medicine, and others receive a placebo (dummy drug). This design gives the most reliable results, however it means leaving some people without any cancer treatment, so, in practise, compromises are often needed. For example, people may be given the test treatment (either new drug or placebo) in addition to a conventional anti-cancer medicine. In this case, any additional effects seen in the group receiving the new medicine can be considered to be due to that. Later trials may compare the effects of the new medicine directly with a conventional treatment.
Clinical trials are performed in a careful, step-wise fashion, to elicit the most accurate and complete information, whilst minimising unnecessary risk to trial participants.
In early studies, tumour size may be measured. Tumour shrinkage is useful to show the medicine has a beneficial effect, but anti-cancer medicines are usually required to show that they can extend people’s lives and this is assessed in the later studies. Overall survival is the best measure, but isn’t always practical, if people are anticipated to survive for many years, or, if they may need additional anti-cancer treatments, which can confuse the study results. Progression-free survival is an alternative measure which is often used. This assesses survival, together with any indications that the cancer is progressing, and often provides the best information to help decide whether a cancer medicine is truly useful.
Further information on how to understand study results and newspaper ‘cancer claims’ is covered in my book (see below).
Taking part in a clinical trial for a new drug can be beneficial. However the drug is still under test and benefit is not guaranteed. Always read the patient information carefully and discuss with your doctor. If you do take part, you can change your mind at any time, for whatever reason.
Should you be interested in clinical trials, the European Medicines Agency (EMA) keeps a database on their website: EU Clinical Trials Register
There is a similar database in the USA at https://clinicaltrials.gov which also covers international studies.
Written by Dr K Thompson, author of From Both Ends of the Stethoscope: Getting through breast cancer – by a doctor who knows. This is an important guide for people with breast cancer, written by a doctor who has had breast cancer herself
Note: This expresses personal views. No warranty is made as to the accuracy or completeness of information given and you should always consult a doctor if you need medical advice.
More Information on clinical trials:
Breast Cancer Trials
Specific trials in the USA but if you find something on there then you could ask your Oncologist if there is anything similar in the UK.
Cancer Research UK trials database
Look & find out what might be available to you for a specific clinical trial
Clinical Trials Gateway
UK based – A searchable database of clinical trials (Not very clear to me that it covers N Ireland)
The Institute of Cancer Research
News and information covering all cancers.
Medical Research Council Clinical Trials Unit centre of excellence for clinical trials, meta-analyses and epidemiological studies looking at all trials which can be searched by criteria.
The National Institute for Health Research – Cancer Research Network
32 local research networks so that more patients can take part.
The National Cancer Research Insitute
Provide information on clinical research.
A place to search for, watch and ask questions about clinical trials near you. Free and independent for patients.
Diet and Exercise Clinical Trial
B-AHEAD 3 (Breast Activity and Healthy Eating After Diagnosis 3)
Researchers at the Prevent Breast Cancer Centre and Christie Hospital (Dr Michelle Harvie, Dr Tony Howell and Dr Sacha Howell) are running a ground breaking study to test the effects of diet and exercise on response and toxicity to chemotherapy for women receiving chemotherapy for secondary breast cancer.
Who can take part?
We are recruiting women with secondary breast cancer who are:
• Starting or have recently started a new course of chemotherapy treatment for secondary breast cancer and are willing and physically able to undertake a diet and exercise programme.
• Have a body mass index (BMI) of 24 or higher. To calculate your BMI please follow this link: http://www.nhs.uk/Tools/Pages/Healthyweightcalculator.aspx
We are recruiting women from the following hospitals:
Blackburn, Burnley, Christie, Leighton, Macclesfield, North Manchester, Oldham, Royal Liverpool, Southampton, Stoke, Tameside, Wigan
For more information about the study please follow this link:
Or speak to your Breast Cancer Team or contact the Research Dietitians at University Hospital South Manchester 0161 291 4412 or email firstname.lastname@example.org