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In
2000, IMS HEALTH’s World
Review reported that
A2B antiulcerants was again the world’s largest third-level
therapeutic class, with sales of $17.4 billion and 11% growth
from 1999.
Since 1996, the leading product
in the A2B class has been AstraZeneca’s Prilosec/Losec
(omeprazole), which has only just been eclipsed by Pfizer’s
statin
Lipitor as the world’s top-selling pharmaceutical.
AstraZeneca held 34.7% of the antiulcerant market in 2000.
Over the 1990s, proton pump inhibitors
(PPIs) like Prilosec began to overtake the older histamine
antagonists, such as GlaxoSmithKline’s Zantac (ranitidine),
as the preferred treatments for ulcers, heartburn and gastro-oesophageal
reflux disease.
In 2000, the second drug in the
A2B class was Takeda’s lansoprazole, marketed in Japan as
Takepron (ranked 13th separately). This is sold by
Takeda’s joint venture with Abbott Labs, TAP, in the US
as Prevacid, and by American Home Products in various
markets as Zoton or Lanzo. Abbott also markets
it in South America as Ogastro.
Behind Zantac and
famotidine (Yamanouchi and Merck & Co’s Gaster/Pepcid)
came Eisai’s Pariet (rabeprazole), co-marketed in
the US with Johnson & Johnson as Aciphex, in
sixth place. Pariet witnessed 334% growth over 1999. The
other PPI is Altana’s Pantoloc/Pantozol (pantoprazole),
which was in 11th place in 2000. It is marketed in the US
by AHP as Protonix, which ranked 14th.
Growth set to
continue
IMS HEALTH’s therapy class forecasting
service Pharmacast
& Beyond calculates
significant growth for the A2B antiulcerants over the next
few years.
A2B class
growth*
*Note: aggregated
figures for the US, Canada, France, Germany, Italy, Spain,
the UK and Japan.
Source: Pharmacast
& Beyond
P&B predicts that the US
A2B market will grow from $9.9 billion in 2000 to $12.6
billion in 2010, a compound annual growth rate of 2.38%.
This increase is attributed to approval of the PPIs for
additional indications; availability of new PPIs; and the
launch of intravenous formulations of PPIs. Similar patterns
are predicted in the other major markets covered by P&B,
with the lowest growth (1.44%) seen in the UK and the highest
in Germany (4.42%).
The growth will be offset by
the availability of generic omeprazole, and vaccines against
the bacterium Helicobacter pylori, now implicated
in the development of most stomach ulcers, could also dampen
the A2B market slightly in the US. On the other hand, if
any PPIs win over-the-counter approval, this could grow
the market.
Prilosec hanging
on...
Andrx received FDA
approval for its generic omeprazole in November 2001, but
will not launch its product until the litigation is settled.
If successful, Andrx and Genpharm will share 180 days of
generic exclusivity for the 10mg and 20mg strength capsules,
with Andrx having sole exclusivity for the 40mg product.
...with Nexium gaining ground
Leading medical experts interviewed
by P&B were of the opinion that esomeprazole would be
highly successful, as they regarded it as being more potent
and having a longer duration of action. They also expected
it to replace many of the existing PPIs provided it is competitively
priced.
This has indeed proved to be
the case. Nexium was launched in the US in March 2001 with
a label covering a comprehensive set of indications, and
had achieved a 12.6% share of new US prescriptions by August
according to IMS HEALTH. Sales
in the first nine months of 2001 reached $295 million; Nexium
was priced at $3.33 to Prilosec’s $3.45. The longer generic
competition for Prilosec is delayed, the more time AstraZeneca
has to switch existing patients to Nexium.
AstraZeneca claims head-to-head
trials show that Nexium has a faster onset of action than
other PPIs, and that it could lead to economic benefits.
At the United European Gastroenterology Week, held in Amsterdam
in October 2001, results were released of a 5,241-patient
study comparing Nexium to lansoprazole (Prevacid). Nexium
achieved greater healing of esophagitis, even in patients
with more severe damage, where lansoprazole’s efficacy appeared
to decline. It also led to greater and faster resolution
of heartburn, the main symptom of erosive esophagitis.
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