UK trials and research studies - The Lily Foundation
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UK trials and research studies

NuPOWER (SPIMD-301) study

Stealth Biotherapeutics is conducting a clinical trial in patients diagnosed with primary mitochondrial disease (PMD) to assess the safety and efficacy of the investigational drug Elamipretide.

What is this study about?

Stealth Biotherapeutics is conducting a clinical trial in patients diagnosed with primary mitochondrial disease (PMD) to assess the safety and efficacy of the investigational drug Elamipretide. So far Elamipretide has been evaluated in over 28 clinical trials including in the previous SPIMM-301 trial.

This study is open to patients with primary mitochondrial disease who have progressive external ophthalmoplegia and exercise intolerance or muscle weakness resulting from a nuclear DNA genetic mutation.

Who can take part? 

You may be eligible to participate in this trial if you:

  • – Are able to walk (with or without a walking aid).
  • – Are 18 to 70 years of age.
  • – Have a diagnosis of primary mitochondrial disease (muscle weakness, fatigue, exercise intolerance).
  • – Have progressive external ophthalmoplegia (drooping eyelids, weakness of eye muscles).

What drug is being tested?

The study drug used in this study is called Elamipretide.

The study will be made up of two different study treatments, Elamipretide or a placebo (dummy inactive medication). You have a 50/50 chance of receiving either the study drug or placebo.

What’s involved in taking part?

During the NuPOWER trial, patients will receive a once daily subcutaneous (under the skin) injection of Elamipretide or placebo for 48 weeks. This can be administered by you or a caregiver.

Participation includes seven study visits to the clinical trial site. Visits will include exercise tests (the 6 Minute Walk Test, 5 Time Sit-to-Stand Test and Triple Timed Up-and-Go Test) and completion of patient-reported questionnaires to assess the safety and effectiveness of the study medication. Participants will also be asked to complete a daily diary to understand how your primary mitochondrial disease affects you. 

Will there be any costs associated with my participation in the study?

You will receive the study medication and all study-related care at no charge. You will be compensated for the time and travel involved for you and a caregiver.

Where is the study taking place?

The study is being run at Cambridge, Newcastle upon Tyne and UCL in London.

Are there any risks?

Blood samples are collected during this study. Taking blood from your arm may cause discomfort, swelling, pain, redness, bruising, bleeding, or infection (infection rarely happens) at the site where the needle is inserted, feeling of light-headedness when the blood is taken and, rarely, fainting.

Injection site reactions have been reported in the majority of patients receiving Elamipretide by SC injection. The nature of these injection site reactions included mild redness, swelling, pain, itching, and bruising. In most subjects the injection site reactions were not a problem and they did not need treatment. Some patients have been treated with topical and systemic antihistamines and/or topical corticosteroids in order to manage the signs and symptoms.

There have been three potential cases of hypersensitivity/allergic reactions resulting from treatment with Elamipretide identified across all development programs.

There may be side-effects and discomforts that are not yet known.

Who will benefit?

There is no guarantee that you will receive any benefits. However, you will be helping others by contributing to medical research. You may feel that you are benefiting in the following ways:

  • Your condition will be checked if your participation in the study lasts. However, services provided and evaluations carried out as part of the study should not be seen as a substitute for a careful evaluation, ongoing medical care, or follow up by your family/personal doctor.
  • The study drug may help to relieve your symptoms.

How do I find out more?

If you think you might be eligible and are interested in taking part in this research, or would like any further information, please contact the study team directly: 


Department of Clinical Neurosciences, Addenbrooke’s Hospital, Cambridge

Contact study team: [email protected]


Queen Square Centre for Neuromuscular Diseases, 8-11 Queen Square, London, WC1N 3BG

Contact: Iwona Skorupinska [email protected]

Tel: 0203 108 7515


Louise Germain [email protected]

Tel: 0203 108 6308


Clinical Ageing Research Unit (CARU), Newcastle University, Campus for Ageing and Vitality, NE4 5PL

Contact: Helen Pilkington (Clinical Research Nurse) [email protected]

Tel: 0191 208 1250