GlaxoSmithKline won approval to market its combination diabetes drug Avandamet for first-line use yesterday, offering a boost to a product that has been held back by manufacturing problems.
Along with its sister product Avandia (rosiglitazone), Avandamet (rosiglitazone and metformin) brought £1.3 billion ($2.4bn) into GSK’s coffers in 2005, despite the latter having been subject to supply constraints that led it to be temporarily removed from the market.
Broader use of Avandamet, along with the launch of another combination product Avandaryl (rosiglitazone plus glimepiride) is expected to drive sales of the franchise to more than $2.8 billion this year, according to analysts, and this will be helped particularly by Avandamet’s return in June, according to Chris Viehbacher, president of the US pharmaceuticals business at GSK.
The manufacturing compliance problems, centered at one of GSK’s facilities in Puerto Rico, are largely resolved but have still held back production of Avandia, the calcium antagonist Coreg (carvedilol) and long-acting antidepressant Paxil CR (paroxetine), as well as Avandamet.
GSK has high expectations for the Avandia franchise, despite the looming threat of competition from the DPP-4 inhibitors, with Novartis’ Galvus (vildagliptin) and Merck & Co’s Januvia (sitagliptin) both submitted for approval and tipped to create a market valued at around $3 billion by analysts at Morgan Stanley.
Viehbacher, in comments made at a Morgan Stanley conference earlier this month, said he believes Avandia, Avandamet and Avandaryl will shrug off competition from the DPP-4 inhibitors
The emerging treatment paradigm in type 2 diabetes is combination treatment, he said, so even if the DPP-4 inhibitors reach the market they will likely be seen as complementary to existing drugs, particularly as relatively few patients are actually meeting their treatment goal - a glycated haemoglobin level of less than 7% - at the moment.
In addition, two major new studies of rosiglitazone – DREAM and ADOPT – should encourage use by inspiring clinician confidence in the drug and potentially expanding the population eligible to receive it. The 4,000-patient DREAM study is looking at the potential of rosiglitazone and ramipril in preventing diabetes in at-risk patients, while ADOPT is seeing if GSK’s drug can have an impact on disease progression.
Evidence of the strength of the Avandia franchise is that it largely maintained its market share – about 11% o the US market in terms of prescriptions – despite the supply problems in recent months and the fact that arch-rival Takeda launched its combination product ActoPlus Met (pioglitazone and metformin) last year.
Viehbacher also noted that recent changes in labelling to reflect a risk of macular oedema and heart failure with rosiglitazone (as well as pioglitazone) have not held back the product has clinicians are comfortable about monitoring patients for these side effects.
