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* GSK drug ahead of similar ones from Teva and AstraZeneca
* Under-the-skin injection set for filing this year
* Data on GSK's mepolizumab presented at Munich congress
* NEJM editorial questions cost-effectiveness of new drugs
By Ben Hirschler
LONDON, Sept 8 (Reuters) - Cost-effectiveness is seen as achallenge for a new group of biotech lung drugs that haveproduced promising results in clinical tests, of which the firstis likely to be launched next year by GlaxoSmithKline.
Rival firms are racing to develop similar injectable drugsfor patients with severe asthma, who do not respond adequatelyto traditional inhalers, in pursuit of a new market thatanalysts believe may be worth around $7.5 billion in annualsales.
GSK, the leader in asthma treatments since launching itsVentolin inhaler in 1969, consolidated its position in the newfield by presenting late-stage Phase III data on itsexperimental drug mepolizumab at the European RespiratorySociety congress in Munich on Monday.
It had already said in March that mepolizumab reducedserious asthma attacks, known as exacerbations, by around 50percent compared to placebo and cut the need for potentiallydamaging oral steroids, without giving full details.
An editorial in the New England Journal of Medicine (NEJM),where the results were also published, said the data werepromising and the drug's side effects looked acceptable, but itwas unclear how widely it should be used.
Mepolizumab is a so-called anti-interleukin-5 antibody drugthat depletes a type of white blood cells known as eosinophilsinvolved in lung disorders and is expected to help around halfthe estimated 2 million patients in developed markets withsevere, difficult-to-treat asthma.
Parameswaran Nair, an asthma expert at Canada's McMasterUniversity, said in the NEJM editorial that the data did notsuggest all patients with eosinophil-related severe asthma wouldneed such a treatment, which he expected to be "expensive".
He noted that patients on placebo in one of two studies also had a "remarkable" 50 percent drop in exacerbations, simplyby adhering properly to prescribed conventional therapies, whichwas likely to be more cost-effective.
"This finding would suggest that most patients in thisclinical trial might have had improvement in symptoms withoutmepolizumab simply by the institution of good clinicalpractice," he wrote.
PRICING UNDER WRAPS
GSK, which faces competition from similar drugs beingdeveloped by Teva Pharmaceutical Industries andAstraZeneca, said it was premature to talk about pricebut added it planned cost-effectiveness studies to show thevalue of its new product.
Analysts have estimated the new class of drugs might cost$10,000 to $15,000 per patient a year.
GSK plans to submit an under-the-skin mepolizumab injectionfor regulatory approval before the end of 2014, while Teva aimsto file reslizumab in the first half of 2015. AstraZeneca's benralizumab is further behind in development, although it isseen a potentially potent competitor.
"There are currently no options, so we will be the firstinto the marketplace," said Steve Yancy, GSK's developmentleader for mepolizumab.
Xolair, from Novartis and Roche, is theonly biotech asthma drug sold at present, but it works in adifferent way to the new batch of products and is only indicatedfor allergic asthma.
The new class of medicines are also being investigated forthe treatment of chronic obstructive pulmonary disease (COPD),which is linked to smoking.
AstraZeneca earlier reported that benralizumab did notreduce COPD exacerbations in a mid-stage trial, although it diddemonstrate clinically significant improvements in lungfunction. (Editing by Louise Heavens)
