Canadian study (VECTOR) presented at the 2009 American Urological
Association Annual Meeting
CHICAGO, April 30 /CNW/ - Patients with overactive bladder (OAB) treated
with solifenacin reported significantly lower incidence and severity of dry
mouth, an often intolerable anti-cholinergic side effect, than those treated
with oxybutynin immediate-release (IR). This was one of the key findings
contained in the VECTOR (VEsicare in Comparison To Oxybutynin for oveRactive
bladder patients) study presented April 28, 2009 at the Late-Breaking Science
Forum of the 2009 American Urological Association annual meeting in Chicago.
The VECTOR study compared the tolerability of solifenacin versus
oxybutynin IR for the treatment of OAB. A secondary objective was to assess
the efficacy of solifenacin versus oxybutynin IR for the treatment of OAB.
"Findings from the VECTOR study are very encouraging," said Sender
Herschorn, MDCM, FRCSC, Professor and Chair of the Division of Urology at the
University of Toronto and attending Urologist and Head of Urodynamics
Laboratory at Sunnybrook Health Sciences Centre in Toronto, Canada. "The fact
that some patients discontinue treatment for OAB because of intolerable side
effects counters our best efforts to encourage them to seek treatment which
could improve their quality of life. It is important for medical
professionals, as well as the patients themselves, to be aware of treatment
options to optimize the management of OAB."
Patients in the VECTOR study were adults over the age of 18 with OAB
symptoms for (greater than or equal to) 3 months (urgency with or without
urinary incontinence, usually with frequency and nocturia) and as documented
in a 3-day patient diary: (greater than) 1 urge episode/24 hours (average) as
well as (greater than or equal to) 8 micturitions/24 hours (average). Overall,
132 patients were recruited from 12 Canadian sites.
In this multi-centre, prospective, randomized, double-blind,
double-dummy, 8 week study, solifenacin was associated with a superior
tolerability profile compared to oxybutynin IR. Patients on solifenacin
experienced a 48 per cent lower incidence of dry mouth and a lower severity of
dry mouth, of which 75 per cent were mild, compared with patients taking
oxybutynin IR (p=0.001). The findings also revealed significantly fewer
withdrawals due to dry mouth as well as fewer overall adverse events
(p=0.009), and fewer treatment related adverse events (p=0.0093) compared to
oxybutynin IR. Both solifenacin and oxybutynin IR improved OAB symptoms and
Solifenacin, a competitive muscarinic receptor antagonist, has not had
its side effect profile directly compared with oxybutynin IR until this study.
"It is hoped that these study results will make more people aware of a better
tolerated treatment choice," said Herschorn.
OAB is a chronic medical condition that is characterized by the sudden,
involuntary and sometimes uncomfortable need to urinate any time during the
day or night. OAB occurs when the bladder's smooth muscle squeezes while the
bladder is still filling instead of when it is completely full, sending a
signal to the brain that results in the urge to urinate. The condition is
associated with poor quality of life that may result in significant social,
psychological, occupational, domestic and physical stigmas. It is estimated
that 12 to 18% of Canadians suffer from OAB.
Vesicare(R) (Solifenacin Succinate) is a once-daily oral medication and
is indicated for the treatment of overactive bladder in adults with symptoms
of urinary urgency, urge urinary incontinence, and urinary frequency. It is
not indicated for the management of stress incontinence, which can occur when
the bladder leaks urine during exercise, coughing, or sneezing.(1) Vesicare
has high affinity for muscarinic receptors in the bladder, which control the
detrusor muscle and cause it to relax. This allows the bladder to fill
normally and reduces the sense of urgency that a patient feels. In clinical
studies, the most common side effects reported with Vesicare were dry mouth
and constipation. Patients may also experience dry eyes, urinary retention,
and blurred vision. Vesicare was approved by Health Canada in February 2006.
About Astellas Pharma Canada, Inc.
Astellas Pharma Canada, Inc. is highly focused on customers and their
needs and is committed to making a difference in urology. The company also
seeks to develop breakthrough products in infectious disease, immunology,
dermatology and cardiovascular disease. Astellas Pharma Canada, Inc. is one of
the Astellas Group of companies in North America and an affiliate of Astellas
Pharma Inc., located in Tokyo. The organization is committed to becoming a
global category leader by combining outstanding research and development and
marketing capabilities. Additional corporate information is available at
(1) Vesicare Product Monograph, as at July 24, 2008
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