Clinical trials: Around half of new treatments perform better than existing treatments

October 16, 2012

On average, new treatments perform better in clinical trials only slightly more often than existing treatments, according to a new systematic review published in The Cochrane Library. The fact that experimental treatments are not more effective may seem disappointing, but the authors of the review say their findings satisfy an important ethical requirement for clinical trials.

Randomised trials compare the effects of one treatment to another. In a patients are randomly allocated to different treatment groups to ensure that like will be compared with like. When a new treatment is being tested, it is hoped or even expected that it will be better than the established treatment with which it is being compared. These expectations lead to an . If the researchers already know that one treatment is better, they would be knowingly allocating some people to an inferior treatment. If randomised trials are to be ethical, therefore, only half of new treatments should turn out to be better than existing ones.

Cochrane researchers looked at evidence from 743 publicly funded randomised trials involving 297,744 patients in total. The trials included new, experimental treatments for cancer and neurological disorders, as well as a range of other diseases. On average, only very slightly more than half of new treatments proved to be better than established treatments.

"When we compared the effects of new treatments to established ones, the pattern was almost symmetrical. This is good news, because it means researchers genuinely don't know whether new treatments are going to be any better," said lead researcher Benjamin Djulbegovic, who works at USF Health , and the H. Lee Moffitt Cancer Center & Research Institute, at the University of South Florida in Tampa, Florida, US. "So, overall, what we show is that we can expect the new treatments to perform better a little bit more often than established treatments, at least in publicly funded trials like the ones we considered."

The researchers found the same pattern in trials going back five decades. The results provide an answer to the question posed 15 years ago in the British Medical Journal by Iain Chalmers, a founder of the Cochrane Collaboration and one of the authors of the review. "In 1997, in a letter published in the BMJ, I asked 'What is the prior probability of a proposed new treatment being superior to established treatments?' I think this review currently provides the best answer to that question," said Chalmers.

Explore further: Drugs reduce bone cancer damage but clinical guidance remains non-specific

More information: Djulbegovic B, Kumar A, Glasziou PP, Perera R, Reljic T, Dent L, Raftery J, Johansen M, Di Tanna GL, Miladinovic B, Soares HP, Vist GE, Chalmers I. New treatments compared to established treatments in randomized trials. Cochrane Database of Systematic Reviews 2012, Issue 10. Art. No.:MR000024. DOI: 10.1002/14651858.MR000024.pub3

Related Stories

Drugs reduce bone cancer damage but clinical guidance remains non-specific

May 15, 2012
Bone cancer-related fractures and pain can be reduced by drug treatment, but no one drug is superior, according to a review published in The Cochrane Library. Researchers undertook a systematic review of the current evidence ...

Music reduces anxiety in cancer patients

August 10, 2011
(Medical Xpress) -- Cancer patients may benefit from sessions with trained music therapists or from listening to music. A new Cochrane systematic review shows using music can reduce anxiety in cancer patients, and may also ...

Exercise may improve quality of life during and after cancer

August 14, 2012
Exercise may improve quality of life for people with cancer, according to Cochrane researchers. In two separate Cochrane systematic reviews, the authors gathered together evidence showing that activities such as walking and ...

Recommended for you

Mouse model of human immune system inadequate for stem cell studies

August 22, 2017
A type of mouse widely used to assess how the human immune system responds to transplanted stem cells does not reflect what is likely to occur in patients, according to a study by researchers at the Stanford University School ...

Scientists find RNA with special role in nerve healing process

August 22, 2017
Scientists may have identified a new opening to intervene in the process of healing peripheral nerve damage with the discovery that an "anti-sense" RNA (AS-RNA) is expressed when nerves are injured. Their experiments in mice ...

Researchers offer new targets for drugs against fatty liver disease and liver cancer

August 22, 2017
There may no silver bullet for treating liver cancer or fatty liver disease, but knowing the right targets will help scientists develop the most effective treatments. Researchers in Sweden have just identified a number of ...

Make way for hemoglobin

August 18, 2017
Every cell in the body, whether skin or muscle or brain, starts out as a generic cell that acquires its unique characteristics after undergoing a process of specialization. Nowhere is this process more dramatic than it is ...

Bio-inspired materials give boost to regenerative medicine

August 18, 2017
What if one day, we could teach our bodies to self-heal like a lizard's tail, and make severe injury or disease no more threatening than a paper cut?

Are stem cells the link between bacteria and cancer?

August 17, 2017
Gastric carcinoma is one of the most common causes of cancer-related deaths, primarily because most patients present at an advanced stage of the disease. The main cause of this cancer is the bacterium Helicobacter pylori, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.