21 May 2013

Biotherapies and rare diseases: focus on a medical revolution

Illustration for article: Biotherapies and rare diseases: focus on a medical revolution
For more than 20 years, the AFM-Telethon supports the development of innovative therapies that benefit rare diseases and medicine as a whole.

The vast majority of rare diseases, which affect 3 million people in France, do not benefit from therapeutic solutions. This is why for more than 20 years the AFM-Telethon supports the development of innovative therapies. Treatments that are beginning to bear fruit for rare diseases and that also help advance medicine as a whole.

Rare diseases, a public health issue

Rare diseases are a real public health issue. If each of them affects less than 1/2000 individuals, according to the European Union, over 30 million people are affected by one of the 5000 to 8 000 rare diseases. In France, more than 3 million people are affected. Five new diseases are described every week in the medical literature.

Biotherapies: a medical revolution in progress

Mostly of genetic origin, rare diseases can be treated with biotherapies. Unlike the conventional pharmacological approach that will generally only provide symptomatic treatment and require repeated administration throughout life, with biotherapies, a definitive cure is possible.Two major avenues are being explored:

Gene therapy, predominantly supported by the AFM-Telethon in France, involves the introduction of a gene medicine into the cells of the diseased organ to correct the genetic defect responsible for the disease.

Thanks to the pioneering work supported by the AFM-Telethon, the first convincing clinical proof was provided for rare genetic disorders of the blood (immunodeficiencies including “bubble babies”), the brain (adrenoleukodystrophy) and the retina (Leber’s congenital amaurosis). The first gene therapy medicine recently obtained marketing authorisation in Europe for familial hyperlipidemia, a rare disease.

Cell therapies, also called “regenerative medicine”, use cells to reform tissues and organs. Even though some indications of cell therapy may involve differentiated cells (called adult cells), pluripotent stem cells are generally used. These cells have the ability to proliferate on a large scale and to transform into any cell type (for embryonic stem cells). The cell types with therapeutic potential that we know how to produce from these stem cells is constantly increasing (central and peripheral neurons, liver, blood, heart, pancreatic, bone, skin, retina, auditory...).

The I-Stem laboratory, created by the AFM-Telethon and Inserm, develops treatments based on the potentials of pluripotent stem cells and their application to rare genetic diseases. Clinical trials are scheduled for cutaneous complications of sickle cell anaemia or neurodegenerative diseases (Huntington's disease).

Promising prospects for common diseases

Advances in the field of rare diseases equally benefit common diseases.

  • Progeria, an extremely rare disease (2 cases in France), characterised by accelerated ageing, shares common mechanisms with physiological ageing (progressive) and accelerated ageing induced by cancer chemotherapy or triple combination therapy for AIDS. The trials offer opportunities for patients with cancer or AIDS.
  • The deficiency in the mitochondrial respiratory chain observed in Leber’s hereditary optic neuropathy, a rare vision disease, is common to the most frequent diseases (Parkinson's disease, accelerated ageing’s disease, cancer). The ability to deliver a therapeutic gene into the mitochondria - the powerhouse of the cell - opens the way for the treatment of mitochondrial deficiencies in frequent pathologies.
  • Beta-thalassemia, a rare genetic disease affecting red blood cells, shares the same genetic origin as sickle cell anaemia, which concerns a large proportion of the African, black American, Mediterranean and Asian populations. The gene therapy developed for beta-thalassemia will be extended to sickle cell anaemia.
  • The regenerative cell therapies tested for the treatment of heart disorders observed in many myopathies were quickly applied to heart failure following an infarct.
  • Cell therapy of the skin intended for certain genetic skin diseases or for skin complications of genetic diseases is applicable to the treatment of severe burns as well as chronic skin ulcer complications related to type II diabetes and severe venous deficiencies.

Finally, the trend towards medicine that is specifically tailored to each patient, taking into account his/her genetic, metabolic, and environmental heritage (“the right treatment, for the right patient, at the right time”), will be based on the model developed for rare diseases.

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