PORTRAIT OF DUCHENNE – Gene replacement therapy

 

In the first interview of our series “Portrait of Duchenne”, La Fondation La Force talks with Dr. Jeffrey Chamberlain, a geneticist at the University of Washington, Seattle, about adenovirus-associated (AAV) micro-dystrophin gene replacement therapy.

Our journey at Fondation La Force travels the road of discovery with parents and friends to find new experimental treatments and the most promising research for children and adults with Duchenne muscular dystrophy (DMD). In November 2016, we went to the 14th Action Duchenne International Conference in London, UK, to meet with the international DMD community on your behalf. We interviewed leading researchers, pharmaceutical company representatives, other foundations, families, children and more! Our new series of blogs about these encounters will bring new hope and inspiration.

 

 Why start with gene replacement therapy?

This promising therapy is not far from clinical trials. If all goes well, treatment of the first patient will probably begin in the coming year. It directly treats the cause of Duchenne muscular dystrophy (DMD) – a lack of dystrophin in muscle cells. A synthetic form of the dystrophin gene will be injected into the bloodstream and delivered to muscles by an adenoviral delivery system. If it works, muscles will begin to produce the missing dystrophin protein. One single treatment may last for 10 or 15 years, predicts Dr. Chamberlain, but the duration of potential benefits are still unknown.

 

 

In the video, Dr. Chamberlain answers our questions about gene replacement therapy:

What’s the idea behind gene replacement therapy?

The idea behind gene replacement therapies is to develop a synthetic or more of a “normal” version of the dystrophin gene and find a way to deliver it back into the muscles to replace the defective dystrophin gene.”

 

How do you deliver the synthetic gene into the body?

The idea is to make this synthetic gene, put it into a small delivery vehicle, inject it right into the bloodstream and then it just, all by itself, leaks out of the bloodstream and goes to the muscles and starts making the missing protein.”

 

How long will one treatment last?

“The other thing we don’t know is how long this therapy will last for. Our study so far suggested it’s a fairly long-lasting treatment, but it is something that might need to be replaced in 10 or 15 years. By ‘replace’, I mean to do a repeat administration.”

 

What’s the name of this process?

The miniaturized gene that we’ve developed, we call a micro-dystrophin, because it’s so much smaller than the dystrophin. The delivery vehicle is referred to as AAV, which is the name of the virus that it was made from, and together… we usually just refer to it as a systemic vector gene delivery system.”

 

Can gene replacement therapy cure DMD?

“The gene replacement technology will fix the muscles that are there, but an older patient that’s lost a lot of muscles will probably only make a partial recovery, so that’s why I say it’s a little short of a cure.”

 

What’s the timeline for treatment?

The timing is a little hard to predict, because it depends on a lot of regulatory approval and, you know, getting everything in place and showing the safety, but a lot of that has been done, and Solid GT, I know, is hoping to apply to begin a human trial very soon and, if everything goes well, the first patients will be treated in the next year.”

 

Are you excited about the next steps in development?

“We have something that we think is going to be effective, and we’re very excited to put it to the test.”

 

Who is Dr. Jeffrey Chamberlain?

Dr. Jeffrey Chamberlain has worked on gene replacement therapy for 25 years.

  • He is Professor, Dept. of Neurology, Medicine and Biochemistry, McCaw Endowed Chair in Muscular Dystrophy, University of Washington, Seattle, Washington, USA
  • Author of Duchenne Muscular Dystrophy: Advances in Therapeutics (Neurological Disease and Therapy)
  • Director of the Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, Seattle, Washington, USA
  • Scientific Advisory Board member, Solid GT, subsidiary of Solid Biosciences, a Cambridge, MA-based life-science company committed to DMD research

 

Up next:

To receive the next interview in our series “Portrait of Duchenne”, please subscribe to our newsletter.

Our next portrait: Utrophin with Michelle Avery of Summit Therapeutics

 

Acknowledgements

We thank the Action Duchenne UK team, who received us with open arms and gave us access to all key speakers at their conference. Because of their generosity, we can spread this hopeful information to the Canadian DMD community.

 

To know more about the Action Duchenne conference :

Logo-Action-Duchenne

 

Special Thanks to Daniel K Cooper and Alain Lagadic

February The Rare Disease Month

Did you know that February is the Rare Disease Month?

 

DMD is also a Zebra

Because it manifests itself only rarely, Duchenne muscular dystrophy (DMD) falls within the rare diseases category. It is also a treatment orphan.

Since this is February, it seemed normal for us to tell you about it.

The zebra has been used as a symbol for rare diseases since about 1940. This comes from a quote by Dr. Theodore Woodward: “When you hear the sound of hooves behind you, do not expect to see a zebra”. This is the metaphor Dr. Woodward used to teach students basic concepts about the diagnosis of a disease: when examining a patient’s symptoms, it’s better to think of a horse rather than a zebra. It’s a fact that horses are hoofed animals more commonly encountered than zebras, so you should automatically assume that if you hear the sound of hooves, it should be a horse, not a zebra, right?

Conversely, if we can’t confirm a common disease, it may be because it is a zebra, and continue the research among the approximately 7,000 known rare diseases. This inevitably results in very long diagnosis delays, along with a lot of consequences this entails.

A few distinctions …

A rare disease is defined as a disease that affects less than 1 in 2000 (DMD affects 1 in 3500-5000, which makes it a rare disease).

The RQMO estimates that, in Québec, nearly one in 20 is afflicted by or carrier of a rare disease, for a total of nearly 500,000 Quebecers. Many rare diseases are chronic, progressive and fatal. The CORD estimates approximately, 3 million Canadians and their families face a debilitating disease that severely impacts their lives.

Nearly 75% of these diseases affect children and about 80% of them are genetic.

A few examples of rare diseases: cystic fibrosis, Duchenne muscular dystrophy, Huntington’s disease, autoimmune myasthenia and Angelman Syndrome.

The term “orphan disease” is often confused with the term “rare disease” because the vast majority of rare diseases are orphans in many ways.

There are approximately 350 orphan drugs for about 7000 rare diseases.

A medical condition is referred to as an orphan disease if there is no treatment for the disease other than treating the symptoms, as is the case for DMD: for example, prednisone is a medication that has an effect on the symptoms but not on the cause of the disease.

The rarity of these diseases creates obstacles and needs for afflicted people both in our health system and in society in general.

The Quebec Coalition for Orphan Diseases (RQMO) works to provide information and support to patients, their families, and healthcare professionals. Their website is full of relevant information both for professionals and caregivers. Being rare, these diseases are often of little interest to researchers and organizations who fund research. The RQMO aims to advance knowledge about the various rare and orphan diseases by promoting exchanges between patients and researchers.

The Canadian Organization for Rare Disorders (CORD) is Canada’s national network for organizations representing all those with rare disorders. CORD provides a strong common voice to advocate for health policy and a healthcare system that works for those with rare disorders. CORD works with governments, researchers, clinicians and industry to promote research, diagnosis, treatment, and services for all rare disorders in Canada.

February 28Th is the Rare Disease Day to raise awareness amongst the general public and decision-makers about rare diseases and their impact on patients lives.

We wish to emphasize that the information contained in this article come mainly from the RQMO website and the CORD website.

We thank them.