Lipitor foreshadows approaching patent cliff for other leading drugs

For the past several years, drug industry experts have spoken in terms of the “patent cliff,” the period when the patents covering several blockbuster drugs are set to expire, thus leaving their manufacturers with a big, gaping hole in their revenues as those drugs face competition from generics.

Of all the drugs on the patent cliff, Pfizer’s cholesterol medication Lipitor (atorvastatin calcium) is by far the best known, not to mention the drug with the highest revenues of any drug in history, with more than $7 billion in 2010 sales in the United States alone. When Lipitor’s patent expired on Nov. 30, 2011, thus opening the drug to competition from Ranbaxy Labs’ generic version, it provided some insight of where the market for cardiovascular drugs is heading.

According to a report released in December by market research firm Decision Resources, expiration of patents covering blockbuster drugs that treat dyslipidemia, and subsequent competition from generics, will decrease the size of the market by nearly $6 billion in the United States, the United Kingdom, Germany, France, Italy, Spain and Japan through 2020. Patent expirations, according to the report, will result in a decrease of nearly $19 billion in sales between 2010 and 2020; the market had sales of $29 billion in 2010. Other drugs facing patent expiration include Merck’s Zetia (ezetimibe) and Vytorin (ezetimibe and simvastatin), Abbott’s Niaspan (niacin extended-release), and AstraZeneca’s and Shionogi’s Crestor (rosuvastatin calcium), which had sales of $3.8 billion in 2010, according to IMS Health.

A similar phenomenon is occurring in the market for drugs to treat high blood pressure. According to a November Decision Resources report, the size of that market will decline from about $26 billion in 2010 to $20.5 billion in 2020 in the same seven countries named in the dyslipidemia report. The decline also is thanks to the loss of patent protection for drugs to treat the condition, particularly Novartis’ Diovan (valsartan/hydrochlorothiazide). According to IMS Health, Diovan will lose patent protection this year, and Decision Resources expected it to face a decline of more than $1 billion in major markets once generic versions enter the market. The drug had global sales of more than $6 billion in 2010, according to Novartis.

The increasing difficulty of achieving blockbuster sales on drugs targeted toward primary-care disease states, such as cholesterol and hypertension, is spurring many companies to pursue specialty drugs instead. “Emerging agents will find it difficult to penetrate the highly genericized hypertension market because of competition from inexpensive and efficacious generic anti-hypertension drugs,” Decision Resources analyst Taskin Ahmed said. But this doesn’t mean development hasn’t continued.

According to a report released last year by the Pharmaceutical Research and Manufacturers of America, 299 drugs are in clinical development or under review by the Food and Drug Administration for heart disease, including 43 for lipid disorders and 27 for hypertension. Of the drugs for hypertension, four were in, or had completed, phase-3 clinical trials, whereas 10 lipid disorder drugs were in, or had completed, the trials.

Of course, Pfizer isn’t letting go of Lipitor just yet. It’s hoping to get FDA approval to launch an OTC version of the drug — though the record of FDA approvals for OTC statins has so far been unsuccessful — and it has entered deals with PBMs and specialty pharmacy provider Diplomat Specialty Pharmacy to try and ensure that patients keep using the branded version of the drug.

Regardless, the market for heart health drugs has evolved considerably in recent years and is likely to continue evolving, especially as it becomes increasingly dominated by generics.

To view the charts listing the Top 20 hypertension and cholesterol-lowering drugs, click here.