Gene Therapy: Patient Starts Treatment

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Dr John Barranger spoke about his gene therapy research at the Association's Conference in November 1994. Here is the latest news:

A 48 year old woman was the first Gauchers patient to start gene therapy in October 1995 at the University of Pittsburgh Medical Centre, USA. Five patients are to be studied during the first year of the protocol with two to be transplanted at the beginning of 1996.

'We are at the beginning of being able to develop a permanent solution to problems associated with Gauchers disease,' said Dr John Barranger, leader of the research team and professor of paediatrics, human genetics and molecular genetics and biochemistry at the University of Pittsburgh.

Start of Therapy

At the start of therapy, patients receive granulocyte-macrophage colony stimulating factor, or GM-CSF. This substance increases the patient's production of specialised white blood cells (haematopoeitic stem cells) which are primitive cells that have the unique ability to reconstitute the entire bone marrow. The stem cells are then removed from the blood during a procedure called leukapheresis and exposed to a retrovirus that carries the corrective gene for glucocerebrosidase deficiency. Cells that express (transmit) this gene are collected and later given back to the patient as an infusion. The cells return to the bone marrow by a natural homing mechanism.

'We are studying how well these cells will compete with the existing marrow, where they will continue to divide and produce glucocerebrosidase. This study will provide very important information which we hope will result in a significant therapeutic advance,' added Dr Barranger.

'The experiment is the first in a series of studies and will take several years to complete. Cures usually do not come from single experiments, but are the result of careful, thorough science done in both the laboratory and clinic. It is not prudent to expect gene therapy to be an overnight success.

'Several years ago, we developed the first treatment for Gauchers disease using an enzyme that we engineered to enhance its delivery to marrow-derived cells, and it worked. Now we may be able to cure this problem by transferring the gene for the enzyme to the same kind of cells. This possibility is what we are studying.'

Gene therapy studies in Gauchers disease are considered a prototype for treatment of more than 15 inherited disorders.

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Source: Gauchers News March 1996.

© Copyright Gauchers Association 1996