ANALYSTS: ADVAIR'S GROWTH COULD BE IMPEDED BY FDA LABELING PROPOSAL
Future growth opportunity for GlaxoSmithKline's (GSK) best-selling asthma treatment
Advair could be curtailed if the firm places restrictions on the drug's use,
as was recently recommended by federal regulators, say financial analysts.
The FDA put Advair (fluticasone propionate/salmeterol xinafoate) on shaky ground
late last week when it recommended that GSK update its existing product labeling
with new warnings and a medication guide to alert healthcare professionals and
patients that the drug may increase the chance of severe asthma episodes.
Advair was one of three long-acting beta 2-adrenergic agonists (LABAs), a class
of bronchodilators, singled out by the FDA, which warned that although LABAs
are intended to reduce the frequency of asthma attacks, clinical data has shown
that the drugs may make asthma episodes more severe when they occur. The other
products named in the public health advisory were GSK's Serevent (salmeterol
xinafoate inhalation powder) and Novartis' Foradil (formoterol fumarate inhalation
powder).
Current product labeling for LABAs include warnings alerting patients that postmarketing
trials showed the drugs might cause asthma exacerbations in some patients, but
the FDA has asked for a stricter warning stating that Advair, Serevent and Foradil
should not be first-line treatments for asthma.
Wall Street analysts said such a warning would limit the drugs' potential growth.
"In our opinion, Advair's restriction to second line asthma is potentially
a greater concern, as it could reduce the potential future growth opportunity
for Advair by limiting penetration into early/mild asthmatics," Merrill
Lynch analyst Graham Parry wrote in a recent research note.
Current Advair sales would probably not be affected by the proposed labeling
revision, said Parry, who noted that a large proportion of Advair sales are
likely in the second-line setting anyway, and patients who are well-controlled
on Advair are unlikely to be switched onto other medications. However, he noted
that the labeling recommendation is a concern, "particularly given [Advair]
is one of the company's key growth drivers."
GSK said recently that it intends to "work with the FDA to address the
differences of opinion about how best to communicate the benefit-risk profile
of these medicines for optimal patient care." The FDA must negotiate labeling
revisions with drug manufacturers because it doesn't have the authority to force
firms to alter their product labels.