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* Benralizumab effective given once every 8 weeks
* Cuts annual rate of asthma exacerbations by up to half
* AZ aims to take on recently launched GSK, Teva drugs
By Ben Hirschler
LONDON, Sept 5 (Reuters) - AstraZeneca hopes toconvince doctors its experimental injection for severe asthmahas an edge over two approved rivals after clinical trials dataon Monday showed it worked well when given just once every twomonths.
The drugmaker has previously flagged benralizumab, which islikely to reach the market next year, as a potential $2billion-a-year seller.
In contrast to GlaxoSmithKline's Nucala and Teva's Cinqair - two other recently launched antibodytreatments for severe asthmatics - benralizumab works directlyto kill off inflammatory cells called eosinophils.
Researchers, writing in The Lancet medical journal, saidthis meant eosinophil counts were nearly completely depletedafter four weeks of treatment.
AstraZeneca had reported in May that two pivotal Phase IIIclinical trials with the biotech medicine met their goals, butfull details were only released at the annual meeting of theEuropean Respiratory Society in London this week.
Overall, a year's course of benralizumab injections cut therate of serious attacks, known as exacerbations, by between athird and a half in patients with eosinophil-driven asthma whowere already making optimal use of inhalers, the data showed.
Researchers said this was "comparable" to results withNucala and Cinqair, although it was difficult to draw directcomparisons because of patient differences, with somebenralizumab patients less sick than those in rival studies.
Importantly, dosing every eight weeks proved just aseffective as treatment every four weeks, which should givebenralizumab an advantage as rivals must be taken monthly.
Dr Mario Castro of Washington University School of Medicine,who was not involved in the company-funded studies, said in acommentary that less frequent dosing should save money. It mightalso allow the drug to be used earlier and be given to children.
AstraZeneca badly needs new drugs to drive future sales asit copes with patent expiries on older medicines, such as itscholesterol fighter Crestor and stomach acid pill Nexium.Although most focus is on its cancer portfolio, the company alsohas a long history in respiratory medicine.
Tom Keith-Roach, head of the respiratory, inflammation andautoimmune business, sees treating uncontrolled severe asthma asa big opportunity, since this relatively small group of patientsaccounts for half of all asthma-related healthcare costs.
"Analysts estimate the severe asthma biologics market by theearly 2020s to be between $6.5 billion and $10 billion (a year),and we expect to have a competitive share of that based on thisclinical profile," Keith-Roach said.
Analysts' consensus sales forecasts for benralizumabcurrently stand at $485 million in 2021, according to ThomsonReuters Cortellis, against the $2 billion predicted byAstraZeneca in 2014.
The company gave its bullish forecast for benralizumab,along with many other pipeline products, at the time of Pfizer's unsuccessful attempt to acquire it. (Editing by Mark Potter)
