Major drug companies such as Pfizer, Merck and Schering-Plough have begun to market combination drugs that treat different facets of a single condition. Prime examples include Merck's Vytorin (Ezetimibe/Simvastatin), a cholesterol drug, and GlaxoSmithKline's Advair (Salmeterol/Fluticasone), an asthma inhalant.
Vytorin combines Zocor (simvastatin) with another drug, Zetia ((Ezetimibe/Simvastatin), which lowers cholesterol in a different way without the potential for side effects that come along with statin medicines such as Lipitor (atorvastatin).
However the danger is that doctors may not use a high enough dose of the Zocor component in the Vytorin combo pill to get these other benefits.
Researchers at Find/SVP Health Care cite Pfizer's Caduet as another example combining the long-acting calcium channel blocker amlodipine besylate with the synthetic lipid-lowering agent atorvastatin calcium. In doing so Caduet becomes the first drug to treat different ailments with one drug.
In bonding its bestsellers (annual sales of $13.5 billion (€10.3 billion)) to treat patients with both high blood pressure and high cholesterol the researchers pointed out this was Pfizer's strategy to generate a wealth of potential for conditions with myriad symptoms.
Generic versions of Norvasc (amlodipine) are waiting for the end of patent protection for the best selling antihypertensive before hitting the shelves. To counter the threat, Pfizer is combining Norvasc with Lipitor to make its amlodipine treatment superior to the numerous generics likely to hit the market extend its sales life.
Perhaps the most successful example is AstraZeneca's transition from Prilosec to next generation drug Nexium. Combined sales for the two drugs in 2002, the second year Prilosec faced generic competition totalled approximately $6.5 billion, exceeding Prilosec sales in each of the previous years it was on the market.
"The trend is shifting towards having two different drugs in one pill to treat two different conditions," said Find/SVP Health Care consultant Bindu Shah.
"Drug companies get to repurpose warhorse drugs to retain market share. At the same time you can reduce the number of pills people have to take, you have a much better chance of getting them to follow their regimes. The elderly, and cardiac patients, who take multiple pills for numerous conditions, are of special concern."
There's clearly a wealth of potential for conditions with myriad symptoms, or linked disorders like bipolar disease and depression, currently being targeted by Eli Lilly with Symbyax (olanzapine and fluoxetine HCl capsules). Marketing efforts are focusing on doctors, said Shah, but consumers should benefit from slightly lower prices.
Shah also pointed out that there would be potential dangers in combining these kinds of drugs. Some were so new that, even with extensive (and expensive) R&D, the possibility of unexpected compounded side effects was always possible.
The biggest barrier to success might be doctors themselves. Some see in combination drugs a loss of dosage flexibility. "Everyone's watching to see how Caduet performs," he said.
According to Cutting Edge Informtion, generics now account for more than 50 per cent of all prescriptions filled in the US and sales are projected to reach $60 billion by 2007.