Idebenone aka Raxone

The Swiss company Santhera Pharmaceuticals  has been developing Idebenone as a possible treatment for several mitochondrial disorders, including LHON (Leber Hereditary Optic Neuropathy) , Duchene Muscular Dystrophy, and Friederichs Ataxia.  They now use the trade name Raxone® for Idebenone, and have also called it Catena®.  (25907159) (25907158)(25684537)(25483949)

In June 2015 the EU Medicines Agency Committee for Medicinal Products for Human Use (CHMP) recommended authorizing Santhera to market Raxone® for the treatment of LHON. In August 2015 Santhera raised CHF 27.7 million via shares to market Raxone®. Santhera News Site.

Researchers on Idebenone and LHON include:

  • Wellcome Trust Centre for Mitochondrial Research, University of Newcastle, UK
  • Doherty Eye Institute, UCLA, California, USA
  • University of Bologna, Italy
  • Ludwig-Maximilians-University, Munich, Germany.
  • Caritas Medical Centre, Shamshuipo, Hong Kong

 

Idebenone as a LHON Treatment

When given as a drug Idebenone tablets are taken daily by mouth.

Over the last few years, doctors have run clinical trials testing Idebenone as a drug to reduce the amount of eyesight lost when someone is affected by LHON (Leber Hereditary Optic Neuropathy). These have used cell cultures, a mouse model of LHON and then human subjects. (23028832)(22269948)(21859767)(21810891)(21788663)(21769071)(26170609)(25307075)

The trials were for people recently affected by LHON.  There isn’t much information on what benefit, if any, someone who has had LHON for years would get from taking Idebenone.

Patients with the three most common LHON gene mutations (G11778A, G3460A and T14484C) have taken part in clinical trials of Raxone®.   As with any LHON study,  trial results can vary because of the difficulty in getting large enough numbers of patients, but it appears that patients with the T14484C mutation are most likely to benefit, follwed by those with the G3460A mutation, and those with the G11778A are the least likely to benefit.

One study concentrated on defects in color vision sometimes seen as an early symptom of LHON (Protan and Tritan color confusion).  They found that Idebenone (900 mg/day Catena) started early protected color vision. (23263355)

One trial is documented in Clinical experience with Raxone® .  This trial measured benefit in terms of the patients being able to read more letters on an eye chart after around a year of treatment.

(23361264)(23263355)

In the trials, doctors found that Idebenone seems to give benefit to around 1 in 3 people affected by the G11778A mutation, with the chances of benefit higher for the other two main mutations.  This was measuring benefit in terms of the thickness of the Retinal Nerve Fiber Layer as an estimate of the number of Retinal Ganglion Cells damaged by LHON.  The patients who got benefit from Idebenone showed less retinal damage than untreated patients.  In one trial doctors found that treating with Idebenone and vitamins may also speed up recovery from the Acute phase. Untreated patients showed some recovery after around 18 months, while  those who showed some recovery and were treated with Idebenone recovered some sight after around 12 months.  (The doctors noted that “recovery” in this trial meant some reduction of the central vision loss or some “fenestration” or small patches of clearer vision).   (23028832)

Affected people had to take Idebenone every day for at least six months before getting any measurable benefit.  for some patients it was more like two years.  Idebenone may also be combined with other things such as Vitamin C and Vitamin B2. (17573650)(23028832)

So an Idebenone treatment for LHON typically means:

  • Starting treatment as soon as possible after first being diagnosed, while still in the Acute phase of LHON.
  • Taking Idebenone every day.
  • Having medical tests such as OCT to measure the thickness of the Retinal Nerve Fiber Layer every six months.
  • There is a roughly 1 in 4 chance that the Idebenone treatment will help more Retinal Ganglion Cells and Retinal Nerve Fibers survive over the next two years.
  • If Idebenone is showing a benefit, carrying on taking it indefinitely.

So Idebenone is not a “Cure” for LHON, or even a guaranteed way of reducing the damage to the Optic Nerve.  It is still a big step forward, taking us from having no proven treatments at all to having a treatment that at least benefits some LHON affected people.(23028832)

 

What does Idebenone do?

Idebenone, also known as Raxone® is a powerful man-made anti-oxidant  chemical which can fit into the mitochondrial Electron Transport Chain doing the work of Co-enzyme Q10 in transferring high-energy electrons.  It may also help people with dysfunctional Complex I proteins by providing electrons directly from the Mitochondrial contents to Complex III.   Idebenone may also cross the blood-brain barrier more easily than Co-enzyme Q10 as it is a smaller molecule.

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Idebenone is a man-made chemical.  It performs the same function in the body as Co-Enzyme Q10, helping Mitochondria provide energy to the cells.   (25625583)

Idebenone is better than Co-Enzyme Q10 at moving from the bloodstream into the brain and Optic Nerve as the molecules are smaller. The Retinal Ganglion Cells and Optic Nerves are more like extensions of the brain than the other nerves in the body.(25421718)

Co-enzyme Q10 sits inside the Mitochondrial membrane as part of the Electron Transport Chain.  It “catches” high-energy electrons released by Complex I and passes them on to Complex III.  This transfer of electrons is a Reduction/Oxidation process and so Co-Enzyme Q10 is known as an Anti-oxidant. It is one of the many anti-oxidants working as a chain within the Mitochondria and the rest of the cell.  Normally, in the mitochondrial Electron Transport Chain, Complex III depends on Complex I and Complex II to provide its high-energy electrons. As well as doing the work of Co-enzyme Q10 in transferring these electrons, Idebenone might also pick up electrons from chemicals inside the mitochondria, bypassing Complex I and Complex II.  (25262284)

The aim of this is to increase the efficiency of energy (ATP) production in the mitochondria and provide anti-oxidant protection to the chemicals in the cell membrane.  This protection action is to stop the electrons from forming chemicals called Reactive Oxygen Species (ROS), as they damage proteins and other important chemicals.

Both Co-Enzyme Q10 and Idebenone are in a class of chemicals called Quinones, but Idebenone is a smaller molecule than Co-Enzyme Q10.  As well as making it easier for Idebenone to pass through the blood-brain barrier, this may make it easier for Idebenone to move around within the Mitochondrial membrane and pass electrons along.
Idebenone and related short-chain quinones are similar to, but different in structure to Co-enzyme Q10.

The size and shape of a chemical are very important to how well it does its job inside the body. That’s because two or more chemicals often have to touch together and interact with each other.

The LHON gene mutations change the chemical structure, and so the shape, of part of the Electron Transport Chain.  For example, the G11778A mutation changes the Complex I protein.

This change of shape is enough to make it harder for Co-Enzyme Q10 to pick up electrons released by Complex I, but Idebenone seems to “fit better” with the altered Complex I.

Who does Idebenone help?

Idebenone clinical trials have concentrated on treating people who are in the Acute phase of LHON or very recently affected.  The reasons for this are:

  • Idebenone is a “protector”, helping the Retinal Ganglion Cells that are healthy or under stress.  Researchers don’t know if it will have much benefit for someone who has had LHON for years, where the Retinal Ganglion Cells are dead or dormant.
  • It is not yet possible to predict in advance which LHON Carriers will become affected or when.  There is no “predictor” medical test or “early warning” symptom.
  • Idebenone is expensive so putting a LHON Carrier on daily doses “just in case” may not be justified.

Doctors involved in using Idebenone as a LHON treatment think that a person affected by LHON might benefit from taking Idebenone to protect whatever eyesight they have left.

Cosmetic use of Idebenone

If you do a web search for Idebenone you might find many skin-care and other cosmetic products claiming to contain Idebenone.  There are claims that Idebenone “fights aging” as it is a powerful anti-oxidant.

Beware of any publicly available product claiming to include Idebenone.

Even if these products do contain Idebenone, the amouns are tiny.

The clinical trials and proven effects are from high-quality high-purity medical grade Idebenone.

 

 

Bibliography

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