At any given time, almost three million Canadians have serious depression, but less than one third seek help, according to the Centre for Addiction and Mental Health. However, one out of three patients treated for depression do not experience complete relief of their depressive symptoms.
At the 157th American Psychiatric Association (APA) annual meeting in New York City in May, data showed close to 80 per cent of patients treated with the investigational antidepressant duloxetine (proposed brand name Cymbalta) remained free of the emotional and physical symptoms of depression at the end of a 38-week study.
“The primary goal when treating depression is complete elimination of symptoms – both the emotional and painful physical symptoms,” said Dr. Susan Abbey of the Toronto General Hospital of the University Health Network.
Additionally, in two other nine-week studies presented at the APA meeting, it was shown that patients treated with 60 mg per day of duloxetine experienced significant improvements in both mood and physical symptoms after just one week.
“These latest data show that duloxetine holds promise for fast and sustained relief of depression symptoms, potentially allowing more patients to get better quickly and stay better,” said Dr. Abbey.
Duloxetine was safe and well tolerated in a 52-week, open-label study of 1,279 patients with major depressive disorder, and patients in the study who responded to treatment with Cymbalta had a high probability of achieving remission. There were 142 Canadian patients and 11 Canadian sites included in the trial.
Remission rates at 52 weeks in this study were close to response rates (81.8 per cent and 89.1 per cent, respectively), implying that patients who responded had a high probability of achieving complete resolution of their depressive symptoms. These findings were published in the Journal of Clinical Psychiatry.
“Remission is the gold standard for anti-depressant treatment,” said Dr. Sid Kennedy, Psychiatrist-in-Chief of the University Health Network in Toronto. “The fact that over 80 per cent of patients in this study who responded to Cymbalta were still taking it after one year and were virtually free of symptoms is very encouraging.”
This study also showed that Cymbalta was also well-tolerated in long-term treatment. Discontinuation due to adverse events over the entire 52-week study was 17 per cent – a favorable rate given the long duration of the study.
“The higher-than-expected completion rate in this open-label study implies that Cymbalta was well-tolerated in these patients and was effective in helping them relieve their depressive illness,” said Dr. Joel Raskin, Eli Lilly Canada Inc. senior clinical research physician and the lead author of the study.
Low levels in the brain of the neurotransmitters serotonin and norepinephrine have been associated with depression. In addition, researchers have long known that serotonin and norepinephrine act together in the descending pain pathway of the spinal cord to send messages about pain perception.
Physical complaints are a big, often overlooked piece of the symptom and remission puzzle. And experts recognize failure to associate physical symptoms with depression as one of the leading causes of underdiagnosis. This “mind-body link” points to the lingering, unresolved depression that seems to persist when left untreated by current therapies.
Cymbalta may address some of the significant unmet medical needs of depressed patients who have emotional and painful physical symptoms of depression.
In early August, the U.S. Food and Drug Administration approved duloxetine for the treatment of major depressive disorder. Duloxetine is not approved in Canada and is a new therapy that has been submitted to Health Canada for review. Approximately 1,000 Canadians have participated in Cymbalta clinical trials.
As many Canadians suffer from major depression as from other leading chronic conditions, including heart disease and diabetes, according to recent data on mental health from the Canadian Community Health Survey. The World Health Organization estimates depression will be the highest-ranking cause of disability in developed countries by 2020.