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What is MAGENTA?

“During the graded exercise therapy course I began to have episodes of paralysis below the waist. Because of this, my paediatrician stopped the therapy. I have never been able to return to my level of health prior to graded exercise. It rendered me housebound and triggered off a number of new symptoms as well as worsening the severity of my old symptoms and worsening my overall health, mobility and cognitive ability to severe. I went from mild/moderate ME to severe ME following graded exercise therapy.”

patient response to an ME Association survey

    • MAGENTA is a trial of graded exercise therapy in children aged 8-17, diagnosed with ME according to the NICE guidelines.
    • The trial is led by a team of researchers from the University of Bristol. A feasibility trial on 100 children began last year in three UK centres at Bath, Cambridge and Newcastle, funded by the NHS National Institute for Health Research. It is is likely to lead to a much larger trial involving hundreds of children.
    • MAGENTA’s plan for the feasibility trial is justified only by the PACE trial, which has been featured on Retraction Watch for its numerous flaws.
    • In clinical trials on children (under-18s), both the child and their parents/carers must give consent for the child to take part. MAGENTA’s participant-information sheets and consent forms do not mention the controversy over PACE, the many problems with the trial’s analyses, or the harms following graded exercise therapy reported by hundreds of patients in surveys. This raises questions about whether the patients and their parents/carers gave properly informed consent in the feasibility trial, or would be able to do so in the larger trial.

MP letter

This is a letter/email you can adapt and send to your MP to express your concern about the MAGENTA trial (feel free to adapt this if you want to):

[If writing as a posted letter, your address here including email address]

[If writing as a posted letter, MP’s address goes here: you can search for it on the Parliament website]


Dear [Name] MP,

I am one of your constituents.  Please will you take note of and sign the following petition:

“Suspend all trials of graded exercise therapy in children and adults with ME/CFS”.

ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome) is a devastating neurological disease that can leave sufferers bedbound and/or tube fed.

Graded exercise therapy is a controversial psychological therapy that relies on evidence from the now scientifically disputed PACE trial.

We are concerned that trials that investigate graded exercise therapy are potentially harmful to participants.  This is all the more worrying when the participants are children, who may find it harder to withdraw from treatment.

Recent biomedical research shows abnormalities in ME patients’  energy production systems including research demonstrating that cellular metabolism is dramatically slowed. This indicates that ME patients cannot generate the resources to exercise as MAGENTA and other graded exercise studies recommend.

Moreover, at a time where exciting biomedical research is being carried out into ME/CFS worldwide it would seem more pertinent to allocate limited funds into building upon this promising research.

This petition means a lot to me, [as I believe that it has the power to improve treatment for ME/CFS patients like myself]. Your support would be much appreciated.

For more information please visit

Thank you for your time

Yours sincerely,

[Your Name]

What is ME/CFS?

“ME/CFS is an acquired organic, pathophysiological, multi-systemic illness that occurs in both sporadic and episodic forms.  Myalgic encephalomyelitis (ICD 10 G93.3), which includes CFS, is classified as a neurological disease in the World Health Organization’s International Classification of Diseases (ICD).  Chronic fatigue must not be confused with ME/CFS because the “fatigue” of ME/CFS represents pathophysiological exhaustion and is only one of many symptoms.  Compelling research evidence of physiological and biochemical abnormalities identifies ME/CFS as a distinct, biological, clinical disorder.”

A Clinical Case Definition and Guidelines for Medical Practitioners by Carruthers et al,

authors of the International Consensus Criteria for ME/CFS

  • ME/CFS affects multiple systems in the body, including the immune system, nervous system, and endocrine system.
  • 250,000 people in the UK are estimated to have ME/CFS, approximately 1 million in the US, and 20 million worldwide
  • Research shows that patients have problems with their aerobic systems and that metabolic processes in patients’ cells are in a greatly slowed
  • Roughly one in four people with ME/CFS are housebound or confined to their beds
  • The key feature of the disease is that exertion beyond the patient’s ‘energy envelope’ causes a flare-up of all symptoms. In the sickest patients, this exertion can be as trivial as cleaning their teeth or trying to get out of bed.
  • A new infection or sustained over-exertion can cause a serious relapse, which can go on indefinitely. Children who were able to attend school, or adults who were able to work, can become bedbound.
  • ME/CFS has the lowest quality of life out of a wide range of diseases studied, including multiple sclerosis, chronic renal failure, lung cancer, and stroke.
  • ME/CFS patients do not wear a label of debility or illness: many patients do not ‘look’ sick.
  • The most well can work by sacrificing other aspects of their lives.  Even sicker patients may spend brief periods outside the house and appear normal for that time.  Sometimes, patients overexert in order to have brief periods of social interaction or to do necessary tasks, but may require days or weeks of bedrest to recover.

Patients are working together in the virtual world to make things better. #MEAction is a fast-growing, international, patient-led group with thousands of supporters, doing just that. Join in here.

What is PACE?

“I’m shocked that the Lancet published it… The PACE study has so many flaws and there are so many questions you’d want to ask about it that I don’t understand how it got through any kind of peer review.”

Professor Ronald W. Davis, Stanford University


“It’s a mass of uninterpretability… All the issues with the trial are extremely worrying, making interpretation of the clinical significance of the findings more or less impossible.”

Emeritus Professor Jonathan Edwards

University College London

  • The PACE trial is the largest ever clinical trial conducted on ME/CFS. It had 641 patients, took place in six UK centres, and cost £5 million in public funds.
  • PACE compared graded exercise and other behavioural therapies with receiving no therapy.
  • PACE’s main results were published in The Lancet in 2011. Its authors claimed that graded exercise therapy — when added to specialist medical care — was moderately effective, based on patients’ self-reports: but the main analyses listed in the study’s original plan had been abandoned and replaced with others.
  • New analysis (September 2016) shows that only 1 in 10 people showed any additional benefit from graded exercise therapy, according to the original protocol. The proportion who got worse has not yet been reported.


  • The trial used a well-known 100-point scale to measure physical function, in which “0” is severe disability and “100” is good health. In the new analyses, patients were considered to be in the “normal range” for physical function if they scored 60 or more — but they were considered disabled enough to enter the trial if they scored 65 or lower. That is, patients could worsen during the trial and be classed as being in the “normal range” for physical function. Patients with congestive heart failure score only a little worse (57/100). Mathematician and journalist Julie Rehmeyer presented this analysis at a statisticians’ conference and said, “I saw jaws drop.”
  • Both scientists and laypersons pointed out the flaws immediately and their letters were published in The Lancet but no correction notice was issued — meaning that reading the paper would not alert individuals to the paper’s fundamental flaws.


“One of the most damaging cases of bad statistical practice that I have personally encountered in my career as a journalist.”

— Julie Rehmeyer

Mathematician and journalist

  • In 2015, years after PACE’s publication in 2011, journalist and public health scientist Dr David Tuller published a detailed critique exposing the many problems in PACE, quoting harsh criticism of the study from world-leading scientists.
  • Shortly after Dr Tuller’s article, a group of over 40 scientists wrote an open letter to The Lancet, strongly criticising the trial and calling for independent analysis of the data, but were ignored. Other scientists asked for the data from the study so that they could analyse it themselves, but were refused.
  • Now a court has ordered the release of the data. Summary data already published in The Lancet suggest that when the data are analysed according to the original plan, the results for graded exercise therapy will be poor.