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About clinical research

A nurse and a cancer patientMany years of laboratory work go into developing a drug for use in patients. But before they can be approved for wider use, new treatments first need to be shown to be effective and safe in the controlled setting of clinical trials.

And it’s not only new drugs that are tested in clinical trials. Researchers also study new combinations, timing or doses of existing drugs to see if they are more effective than standard treatments.

About clinical trials

There are three main types of clinical trial:

  • Phase 1 - very small trials testing whether a new treatment is safe and finding the best dose to use
  • Phase 2 - fairly small trials testing how well a new treatment works
  • Phase 3 - large-scale trials comparing a new treatment with the current standard treatment

Normally, a treatment must pass all three phases - and be approved by the regulatory authorities - before doctors are allowed to offer it to patients routinely.

As well as testing treatments, clinical trials are carried out to look at new ways to prevent or detect cancer. We currently fund over 180 clinical trials - you can search for these and other UK clinical trials on our CancerHelp UK database. Or if you want to find out more about trials in general, take a look at the pages on understanding clinical trials.

Listen to an audio package about the importance of clinical trials for cancer research, and how they are carried out:

Our unique role

The UK leads the world in the proportion of cancer patients recruited to clinical trials. More than 12% of cancer patients now take part in trials - that’s a greater proportion than in any other European country or the USA.

Cancer Research UK has a unique and pivotal role in cancer clinical trials in the UK. As well as funding doctors who lead the trials, we provide essential UK-wide support to ensure they run smoothly.

We fund seven Clinical Trials Units across the UK, which coordinate a range of large-scale trials. These units provide expertise in trial design and data analysis.

Working with others

A clinical team discussing resultsOur success in developing new and better treatments for cancer is thanks to close collaboration with our many partners.

For example, we fund 19 Experimental Cancer Medicine Centres (ECMCs) through a £35 million joint initiative with the Department of Health. The ECMCs run the earliest trials of potential new cancer treatments. Volunteers on these trials help researchers to assess the promise of treatments for future generations of cancer patients.

Our renowned Drug Development Office underpins the delivery of such early-stage trials through its preclinical drug development work, and by designing, managing and funding early trials.

Our impact

Since the early 1980s, we’ve taken over 100 new drugs into clinical trials. And more than 100,000 patients have taken part in our treatment trials since 1995.

Our trials have led to changes in the way that many different types of cancer are treated, including breast, bowel, lung, skin, prostate and pancreatic cancer. This has improved survival rates and saved hundreds of thousands of lives. Here are just a few examples of our work:


Tamoxifen is considered to the most important drug in the history of breast cancer treatment. 1 Our work has shaped the way this drug is used today. For instance, our scientists showed that giving tamoxifen to younger as well as older breast cancer patients could save an extra 20,000 lives each year worldwide. 2

Blocking the blood supply

We carried out early trials of a promising lung cancer drug called DMXAA, which works by blocking the blood supply to tumours. 3-5

Targeted treatments

We completed the first UK trials of a new generation of highly targeted cancer drugs known as PARP inhibitors. 6, 7 We’re now funding further trials in certain people with breast or ovarian cancer.

Hope for pancreatic cancer

We funded ESPAC-1, the largest ever trial for people with pancreatic cancer. This showed that chemotherapy, along with surgery, could improve survival in patients with operable disease. 8, 9

Paving the way

Our scientists carried out some of the key early clinical trials on breast cancer drugs known as aromatase inhibitors. 10, 11 This work paved the way for anastrozole (Arimidex), an alternative treatment to tamoxifen that is rapidly becoming the new gold-standard of care for some women.

All our work - from research into cancer biology through to clinical trials - would not be possible without the generosity of our supporters.

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  1.  Rea, D., Poole, C. & Gray, R. Adjuvant tamoxifen: how long before we know how long? BMJ 316, 1518-1519 (1998). PubMed link
  2.  Early Breast Cancer Trialists' Collaborative Group. Tamoxifen for early breast cancer: an overview of the randomised trials. The Lancet 351, 1451-1467 (1998). PubMed link
  3.  Rustin, G.J.S. et al. 5,6-Dimethylxanthenone-4-acetic acid (DMXAA), a novel antivascular agent: phase I clinical and pharmacokinetic study. Br J Cancer 88, 1160-1167 (2003). PubMed link
  4. Jameson, M. et al. Pharmacokinetics of 5,6-dimethylxanthenone-4-acetic acid (AS1404), a novel vascular disrupting agent, in phase I clinical trial. Cancer Chemotherapy and Pharmacology 59, 681-687 (2007). PubMed link
  5. Jameson, M.B. et al. Clinical aspects of a phase I trial of 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a novel antivascular agent. Br J Cancer 88, 1844-1850 (2003). PubMed link
  6.  Plummer, R. et al. Phase I Study of the Poly(ADP-Ribose) polymerase inhibitor, AG014699, in combination with temozolomide in patients with advanced solid tumors. Clin Cancer Res 14, 7917-7923 (2008). PubMed link
  7. Plummer, R. et al. First and final report of a phase II study of the poly(ADP-ribose) polymerase (PARP) inhibitor, AG014699, in combination with temozolomide (TMZ) in patients with metastatic malignant melanoma (MM). J Clin Oncol ASCO Annual Meeting Proceedings Part I. 24 No. 18S(June 20 Supplement), Abstract 8013 (2006).
  8.  Neoptolemos, J.P. et al. Adjuvant chemoradiotherapy and chemotherapy in resectable pancreatic cancer: a randomised controlled trial. The Lancet 358, 1576-1585 (2001). PubMed link
  9. Neoptolemos, J.P. et al. A randomized trial of chemoradiotherapy and chemotherapy after resection of pancreatic cancer. N Engl J Med 350, 1200-1210 (2004). PubMed link
  10.  Coombes, R.C., Dowsett, M., Goss, P., Gazet, J.C. & Brodie, A. 4-hydroxyandrostenedione in treatment of postmenopausal patients with advanced breast cancer. The Lancet 324, 1237-1239 (1984). PubMed link
  11. Dowsett, M. et al. Use of the aromatase inhibitor 4-hydroxyandrostenedione in postmenopausal breast cancer: optimization of therapeutic dose and route. Cancer Res 47, 1957-1961 (1987). PubMed link
Updated: 25 September 2009