Cipralex shows fewer side-effects than Efexor
pharmafile | October 25, 2004 | News story | |Â Â Â
Lundbeck says two new studies prove that patients taking its antidepressant Cipralex (escitalopram) gain relief faster and suffer fewer side-effects than those on Wyeth's Efexor.
The Danish company and its US co-marketers Forest say that Cipralex (known as Lexapro in the US) is better tolerated and at least as effective as Efexor (venlafaxine) for patients with major depressive disorder.
The publication of the studies come at a time of unprecedented concern about the safety of the newer SSRI antidepressants, in particular, serious side-effects observed in patients taking GSK's Seroxat (paroxetine) which prompted the UK's ongoing investigation into the leading drugs.
In the UK, the controversy, along with reinforced warnings from the MHRA has seen Seroxat prescriptions fall by 18% over the last year, with Wyeth's Efexor seeming to benefit most, gaining 22% in the same period.
One major benefit of the SSRI class is that it is much more difficult for patients to commit suicide by overdose compared to the older tricyclics, in which cases of fatal toxicity (80% recorded as suicide) is ten times higher.
The UK Office for National Statistics recently showed that overall reported deaths from 1993 and 2002 due to fatal toxicity fell from nine to seven per million population for both sexes between 1993 and 2002.
Efexor is grouped in an 'other' category with assorted antidepressants which are neither SSRIs or tricyclics. The statistics show that death rates for this group – and in particular Efexor – have increased and now exceed those of SSRIs.
Two eight-week studies conducted across the US and eight European countries respectively, compared the efficacy and tolerability of the drugs; the European study attempting to simulate primary care, the US one using higher doses seen in secondary care to treat the severely ill.
Study author Professor Stuart Montgomery of Imperial College School of Medicine said: "The ideal combination for any first-line treatment is good efficacy and good tolerability – this study shows that escitalopram has all the potency of the non-selective SNRIs combined with the good tolerability of the conventional SSRIs.
In both studies Cipralex was found to be at least as effective as Efexor – the anti-depressant famed for its high efficacy and also consistently outperformed it in the tolerance stakes.
The primary care study in Europe also revealed that patients treated with the drug achieved sustained remission on average one week faster than those on Efexor.
Meanwhile, the secondary care study conducted in the US showed the drug to have significantly superior efficacy at 20mg compared to 225mg of venlafaxine, among severely ill patients.
"These results are important because they show we have a treatment at our disposal which is effective without sacrificing the good side-effect profile obviously preferred by patients,said Montgomery.
But Emma Travis, central nervous system analyst at Datamonitor believes it will not have a major impact on the depression treatment market.
"The success of Efexor (venlafaxine) is largely attributed to its unique mechanism and its positioning as a second-line option for patients who have failed first-line therapy with SSRIs," she says.
"In other words, Efexor is usually used after patients have tried one or two SSRIs and found that they were ineffective or have had poor response to them."
One weaknesses in the study is that it does not directly compare the rate of remission achieved by Cipralex compared to Efexor, but instead only looks at the time to remission
Datamontor's Travis says: ["This] may suggest that the overall rate is not improved with Cipralex. Why Cipralex should be any different to the other SSRIs is unclear."
Nevertheless, it seems unlikely that Efexor's position will be challenged by this latest study as it would normally only be used following Cipralex in any case, argues Travis. The more likely scenario is that market share will be taken from the other SSRIs.
When Cipralex came to market after Cipramil, Lundbeck's strategy to switch patients over to Cipralex prior to the arrival in the market of the generic version citalopram was fairly successful. Any impact on the market share of other SSRIs, however, has been less noticeable.
"In terms of cash, Cipralex is not a massive player in the UK market and, with regulatory authorities actively encouraging physicians to use cheaper products (including generic citalopram), it is unlikely based on this latest study that there will be a sudden rush for physicians to switch from well-established SSRIs to Cipralex," says Travis.
Despite this cautious prediction, the drug is expected to be the fastest growing antidepressant in 2004, a forecast 38% increase in sales making it the world's fourth biggest selling antidepressant by the end of the year, led in particular by US sales.
