Genaissance service a potential 'life saver'

Genaissance Pharmaceuticals expansion of its genetic testing service comes after it was revealed there are over 50 approved drugs which prolong the QT interval potentially causing cardiac arrythmias and safety concerns amongst effective anti-arrhythmic agents.

In an interview with DrugResearcher.com Richard Judson, chief scientific officer at Genaissance Pharmaceuticals said that the withdrawal of several major drugs like Seldane and Propulsid have caused Genaissance to look into more gene targets.

Genaissance have fifty issued/pending patents relating to five cardiac ion channel genes associated with LQT's and Judson added that they had an active research program in collaboration with its academic partners, in particular with Mayo Clinical, University of Rochester and Cleveland Clinic.

"Inherited LQT occurs in approximately 1:5,000 where acquired LQT can be as low as 1/100,000 for commonly used drugs to 5 per cent for certain cardiac drugs," he said.

Typical sufferers tended to be mixed although the drugs used to treat both pediatric and adult diseases, and the worst of these (anti-arrhythmic drugs) are used mainly in the elderly.

Genaissance's service intends to help identify experimental drugs that may induce life threatening cardiac arrhythmias before they are brought to market.

The service screens patients for susceptibility for drug-induced cardiac arrhythmias. It achieves this by testing for a common polymorphism in KCNE1, an important cardiac ion-channel gene.

"Gaining the right to screen patients for this KCNE1 polymorphism, which increases a patient's risk of developing a drug-induced arrhythmia, is especially critical for FDA-mandated thorough QT safety trials that now occur in early stages of drug development," he said.

"We are not aware of other commercial offerings for genetic screening for drug induced long QT. However, other genetic/genomic companies and academic centres may offer this capability in a research mode."