Dutasteride (Avodart) + tamsulosin combo cuts prostate enlargement risks: GSK

Dutasteride (Avodart) significantly cuts the risk of urinary retention when combined with tamsulosin in men with enlarged prostate, according to GlaxoSmithkline studies.

Dutasteride (Avodart) and tamsulosin results show that the combination treatment significantly reduces the risk of acute urinary retention or BPH-related surgery by 66% compared with tamsulosin alone, says the study, which have been published online in European Urology.

GlaxoSmithKline’s (GSK) final results from its 4-year CombAT (Combination therapy with Avodart and Tamsulosin) has also shown that combination therapy significantly reduces the risk of BPH disease progression by 44% compared with tamsulosin and 31% compared with dutasteride alone.

“CombAT provides evidence that combination therapy may benefit these men, potentially reducing the long-term risk of disease progression and improving their symptoms.” said Dr Claus G. Roehrborn, principle investigator and lead author of the CombAT study publication.

CombAT enrolled men who had moderate-to-severe symptoms of BPH for the study. Those treated with combination therapy reported a significant improvement in BPH symptoms at 4 years, as measured by the International Prostate Symptom Score (IPSS), with a mean change from baseline of -6.3 points, compared to -3.8 for tamsulosin and -5.3 for dutasteride alone.

Dutasteride (Avodart) and tamsulosin combination therapy was generally well-tolerated and most reported drug-related adverse events were as anticipated from the known safety profiles of the two drugs.

Although there were no significant differences between combination therapy and the two monotherapies in terms of overall withdrawal rates due to drug-related adverse events, the incidence of events in the combination group was greater, with erectile dysfunction and difficulty with ejaculation being the most commonly reported adverse events.

Benign prostatic hyperplasia or prostate enlargement affects nearly 50% of men over 50 years old worldwide.

Benign prostatic hyperplasia is not a life threatening condition but associated symptoms, such as incontinence and the urge to urinate more frequently, can impair the quality of life of men suffering from BPH and their families. If left untreated, symptomatic enlarged prostate can increase the risk of serious long-term complications leading to hospitalisation and surgery.

Benign prostatic hyperplasia progression often leads to more severe symptoms and can cause acute urinary retention, a sudden inability to pass urine, which is always painful and involves treatment with catherisation or prostate surgery. This may have a serious impact on a patient’s quality of life, as can the fear that acute urinary retention may recur.

In the UK there are 3.2 million men over 50 years old with BPH. Of those, only 1.5 million have a diagnosis with just 450,000 men currently receiving medical treatment.

Dutasteride is a dual inhibitor of type 1 and type 2 forms of the enzyme 5-alpha reductase which converts testosterone into dihydrotestosterone (DHT), the primary male hormone responsible for prostate growth and BPH development. Dutasteride monotherapy is indicated for the treatment of moderate-to-severe symptoms of BPH, and to reduce the risk of AUR and prostate surgery in men with BPH.

Tamsulosinis an ?1a-selective alpha blocker used in the symptomatic treatment of benign prostatic hyperplasia (BPH). Tamsulosin was developed by Yamanouchi Pharmaceuticals (now part of Astellas Pharma) and is marketed by various companies under licence, including Boehringer-Ingelheim and CSL.

Boehringer Ingelheim sells tamsulosin in the brand name Flomax, which used for treating non-cancerous enlargement of prostate, medically termed as benign prostatic hyperplasia.

Tamsulosin is expected to go off-patent this month. In September, indian generic firm Wockhardt received US Food and Drug Administration’s (USFDA) tentative approval for marketing tamsulosin hydrochloride capsules.