Advances in genetics coupled with better ways to capture images of the brain may pave the way to a new generation of more effective pain medicines. Advances in genetics coupled with better ways to capture images of the brain may pave the way to a new generation of more effective pain medicines.

The discovery by British researchers of a gene mutation that prevents carriers from sensing pain, announced on Wednesday, is the latest example of a fresh avenue in the hunt for better painkillers.

Pfizer Inc. already has a product in preclinical development based on the new genetic target, which should be ready for human testing in around two years time and could get to market within a decade.

Most pain killers today either rely on mechanisms of action exploited since Egyptian times or result from chance observations of drugs originally developed for other uses.

After years of relative neglect, however, the pursuit of new compounds for treating chronic pain is now one of the most active areas for central nervous system research.

Magdi Hanna, director of the Pain Research Unit at King's College School of Medicine in London, said recent scientific advances had encouraged drug giants like Pfizer and GlaxoSmithKline Plc to step up investment.

Fuelling the drive is technology that allows doctors, for the first time, to see what pain looks like inside our heads.

More powerful magnetic resonance imaging (MRI) scanners and better software mean researchers can track the biological effects of pain by measuring which brain cells are activated, based on how much oxygen is removed from the blood.

"It gives us the objective measure of pain we have been striving for," according to Professor Steve Williams of London's Institute of Psychiatry. "We are able to visualise the functional circuitry of the brain."

Measuring the 'ouch'

Williams and his team will shortly start using functional MRI to analyse the precise impact of different painkillers on patients' brains -- a move that should help speed new drug development.

Scientists also hope to unpick the complex matrix of sensory, cognitive and emotional factors that determine why people feel pain differently and often fail to respond to existing medicines.

For drugmakers like Pfizer, whose new nerve pain drug Lyrica marks one of the few recent advances in pain treatment, the commercial potential is large.

Chronic pain now affects nearly one in five Europeans, according to a large study published last year, and most find existing treatments give only limited relief.

Furthermore, the burden is set grow as an ageing population succumbs increasingly to painful diseases like cancer, diabetes and arthritis.

Despite years of study, the mechanics of pain are still poorly understood, with scientists struggling to understand exactly how nerve fibres detect pain and what the role of other cells might be in the process.

Modern genetics and neuroscience, however, are throwing up new clues and opening potential new biochemical pain pathways for drug intervention.

"We are standing at the dawn of a new era in pain medication and treatment," Damian O'Connell, global clinical leader for Pfizer's analgesic portfolio, told reporters this week.

"The science is starting to explode and our understanding of what is driving pain is becoming more and more focused."

He said Pfizer alone had drugs targeting three different mechanisms of action in clinical trials and another 12 in preclinical development, with rival companies also seeing notable advances.