The US Food and Drug Administration (FDA) has published draft guidance on generic copies of combination drugs for respiratory diseases which could hasten generic competition to GlaxoSmithKline’s (GSK) big-selling Advair brand.
Advair (fluticasone and salmeterol) has already started to lose patent protection in some markets, including the US in 2010, but it remains a key product for GSK.
Sales were around $7.6bn last year across Advair’s approved indications in asthma and chronic obstructive pulmonary disease (COPD), accounting for around 18 per cent of the group’s turnover and an estimated 25 per cent of profits.
Complexities in manufacturing generic versions of Advair that are directly substitutable for the brand have made it remarkably resistant to competition, with Teva and Sandoz both running into difficulties developing their own versions. One complicating factor for would-be rivals is mimicking the delivery profile of GSK’s Diskus inhaler.
The FDA’s new draft guidance provides a simplified framework for companies trying to develop generics of Advair as well as other combination inhaled medicines such as AstraZeneca’s Symbicort (budesonide/formoterol), also a blockbuster with sales of $3bn-a-year.
Analyst Savvas Neophytou at Panmure Gordon notes that the guidelines “essentially require relatively simple preclinical data backed up by a very short clinical trial”, likely only at the lowest approved dose of the reference product.
Moreover, it looks like the FDA will only require bridging data from an asthma trial for approval, even though both Advair and Symbicort are approved for use both in asthma and the fast-growing COPD market.
How quickly generic drugmakers make use of the new guidance to bring their own combination respiratory therapies to market remains to be seen, but the size of the market opportunity suggests they will not rest on their laurels.
Meanwhile, GSK is racing to bring a stable of Advair successors to market, having already started down that path with the approval of Breo (vilanterol/ fluticasone) in May and a filing for Anoro (vilanterol/ umeclidinium), which was recommended for approval by an FDA advisory committee yesterday.
It is also important to remember that the guidance is in draft form, so could be modified during the comment period, while even the truncated clinical requirements could be a disincentive for some low-margin generic manufacturers, potentially limiting the number of competitors in the market and the scale of price discounts.