Changing tides in gene therapy?

The gene therapy market has had limited success with products during the clinical development process.

Due to toxicological complications and poor therapy efficacy, healthcare authorities have suspended several gene therapy trials worldwide; however, research involving novel designs for vectors, methods of introducing 'naked' deoxyribonucleic acid (DNA), and the use of electroporation to improve DNA uptake into cells have been successful in pre-clinical studies.

These new-age technologies are now entering the clinical development stage and approaching the market. The launch of Gendicine in China, the only gene therapy product available in the market, signifies a huge boost for gene therapy, while new analysis from Frost & Sullivan World Gene Therapy Markets reveals that revenue in this industry is expected to total US$150m in 2005.

An increasingly popular method of improving clinical efficiency is to combine gene therapy trials with conventional therapeutics. These combination trials sometimes involve collaborations outside the gene therapy market with companies having established products or expertise in healthcare.

'A second strategy - particularly for companies with fewer products in development - is to work out a suitable exit strategy, should a gene therapy product fail during clinical development,' said Frost & Sullivan industry analyst Phil Webster. 'This involves the objective assessment of a project, which can either be terminated or have its components recycled into a new project.'

The gene therapy market has been the cause of failures and breakthroughs in the treatment of severe diseases. Due to safety concerns, poorly regulated trials, and high levels of clinical attrition, regulatory agencies have stringent authorisation laws about gene therapy. Specific ethics commissions, regulatory divisions, and governmental panels all over the world inspect and monitor trials by gene therapy companies.

According to Frost & Sullivan: 'lack of cellular target specificity is largely responsible for the toxicity issues in gene therapy, as viral vectors, the most commonly used gene delivery system, may infect even healthy cells while transporting genes to the body. There is the danger of the new gene being inserted in the wrong location in the DNA that can possibly cause cancer or other mutations. Even over-expression of the introduced gene sequences can cause an unfavourable immune reaction.

'The historically associated risks of gene therapy are now lessening, predominantly through scientific advances in gene delivery by industry participants. Regulatory restrictions will diminish if the clinical success rate improves and more products are submitted for approval.'