Asthma drug warning hits GlaxoSmithKline
pharmafile | November 21, 2005 | News story | Sales and Marketing |
Sales of GlaxoSmithKline's number one product asthma drug Advair could be hit by new safety warnings imposed by the US medicines regulator.
The FDA says GSK's Advair and other long-acting beta 2 agonists have been associated with increased risk of severe asthma exacerbations and asthma-related death, and should carry warnings about the serious side-effects.
Worse still, the regulator says Advair should not be used as a frontline treatment, and only considered when patients fail to respond to other asthma drugs, such as low-to-medium dose inhaled corticosteroids.
The FDA has ordered the new restrictions after examining results from GSK's own SMART trial of salmeterol, the beta 2 agonist used in Advair's two-in-one formulation with corticosteroid fluticasone.
The study showed 13 patients out of over 13,000 on salmeterol died in an asthma-related death compared to just three in a similar sized group on placebo.
The trial only studied salmeterol and not Advair's salmeterol/fluticasone combination, but FDA scientists have extended the same precautions to the two-in-one drug as to its monotherapy brand Serevent.
Advair, known as Seretide in the UK, is the company's best-selling medicine in the US and worldwide, with global sales of £2.15 billion ($3.98 billion) for the first nine months of 2005.
The brand is expected to reach sales of £3.3 billion for 2005, accounting for 15% of the company's total sales.
More than half of Advair/Seretide sales are in the US, and the new restrictions could be a serious blow to prescribing.
GSK has disagreed strongly with the new restrictions, saying they are 'inconsistent' with established US National Institute of Health guidelines, and that the measures could put some patients at danger of uncontrolled asthma.
"Patient safety is of paramount concern to GSK which is why we disagree with the FDA's proposed labelling changes," said Dr Kathy Rickard, GSK's US head of medical affairs for respiratory drugs.
"These proposed labelling changes would reserve the most effective asthma treatment – the combination of inhaled corticosteroids and long-acting beta agonists [LABAs] – until after a patient has failed on other treatment options and therefore may be at risk of severe outcomes, such as exacerbations and potentially death."
The FDA's new warnings also extend to GSK's Serevent (salmeterol monotherapy) and formoterol flumarate, marketed as Novartis' Foradil.
The UK's regulator the MHRA has responded to the US announcement with similar advice, reminding prescribers that LABAs should always be prescribed with corticosteroids. It also said asthma patients with deteriorating asthma should not be initiated on the drugs, and that patients should be monitored closely for the first three months of treatment.
The SMART study found African-American patients at greater risk of respiratory related deaths than Caucasian patients, but said it was not clear if there were underlying genetic reasons for the differences, or if it was relevant to the UK population.
GSK's share price fell 4% in New York when the news broke, and could be under further pressure if Advair sales are seriously affected.
The FDA decision is also bad news for AstraZeneca, which has sought a licence to allow its rival combination product Symbicort to be used without a separate reliever inhaler.
Symbicort combines LABA formoterol with corticosteroid budesonide, and is yet to be approved in the US. AstraZeneca has conducted trials to support Symbicort's use without a separate inhaler, but the new safety warnings seem certain to see this application fail.
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