One doctor calls it the “Holy Grail” of patient drug therapy: a genetic test that can tell physicians why some patients react poorly or differently to opioid prescriptions. Some believe it could revolutionize the field of pain management and result in more effective care of chronic pain patients.
Millennium Laboratories announced the launch of its pharmacogenetic test (PGT) during PAINWeek in Las Vegas, a national conference attended by nearly 2,000 frontline practitioners in the field of pain management.
Millennium is one of the nation’s largest urine drug screening companies, but PGT is a saliva-based test — designed to detect genetic variations in enzymes that influence how a patient’s metabolism processes opioids. That information will help physicians modify dosages, anticipate side effects or change medications for patients who don’t respond well to opioid therapy.
The company first introduced PGT to a select group of physicians in June and is now expanding its use to other healthcare professionals who want to incorporate the emerging science of pharmacogenetics into their practices.
“I’ve been waiting 30 years to do this kind of testing,” said Forrest Tennant, MD, a longtime pain physician in the Los Angeles area. Tennant has long suspected that genetic differences in patients influence how patients respond to opioid treatment.
“A few years ago, I became aware that there was something different about patients. You take two patients who seem to have the same back problem. One patient would need 50 mg of morphine a day and the other would only need 10 mg. It didn’t make any sense, really.”
Tennant says blood and urine drug screens are flawed and don’t tell the full story of how a patient is responding to opioid therapy. Some urine tests failed to detect opioids in patients that Tennant was treating — even though he knew they were taking the medications. He believes PGT testing will give physicians an extra tool that will help them prescribe opioids more effectively.
“Right now I’ve got an awful lot of questions that I don’t have answers for. But at least we’re starting,” said Tennant.
Last month, Millennium announced the start of a large clinical study examining the use of pharmacogenetics in pain management. The study, which will encompass more than 30 trial sites in the United States, will evaluate the relationship between a patient’s genetic variations and clinical outcomes.
“Individual genetic differences in medication metabolism can significantly impact the efficacy of medication therapy in pain care. By identifying patient-specific drug metabolism, pharmacogenetic testing can potentially pave the way for personalized medicine in the field of pain management,” said Angela Huskey, associate vice-president of Clinical Affairs at Millennium.
A Millennium competitor says the science behind pharmacogenetics needs more work.
“I think we’re still very early in the game in understanding which genes you should test for that will make a difference,” said Harry Leider, MD, chief medical officer of Ameritox. “There aren’t many studies out there that will really support that if you test for this gene, it will help you make a decision about how to tailor therapy for a patient.”
But Forrest Tennant is convinced the time has come for genetic testing.
“This is going to be a godsend. For the first time, we have scientific, objective tools at our hands that we can use to justify regimens that are odd and to help our patients,” Tennant says.