The cardiovascular market has been “one of the mainstays of the pharmaceutical industry over the last 20 years but as it matures, sales growth will be negligible as leading brands lose patent protection, according to a new report.

Datamonitor says that the “patent cliff” facing drugmakers is “particularly pronounced within cardiovascular diseases”, with six of the current top 10 brands, totalling $30.9 billion sales in the US, Japan and major EU countries, losing protection between 2010 and 2013. The treatments that are likely to suffer the most include Pfizer’s Lipitor (atorvastatin), Sanofi-Aventis/Bristol-Myers Squibb’s Plavix (clopidogrel) and Novartis’ Diovan (valsartan).

Pfizer is being hit particularly hard and as well as the problems it faces defending Lipitor, the loss of patent protection on the blood pressure drug Norvasc (amlodipine) is already being acutely felt. “Adding insult to injury,” the report says that the New York-based behemoth’s current cardiovascular pipeline is particularly bare after the company dropped the development of the Lipitor replacement, torcetrapib, and the withdrawal of Exubera (inhaled insulin), which some analysts had predicted would generate $2 billion in annual sales but only generated $5 million in the US in the first half of 2007.

Datamonitor cardiovascular analyst Anthony Nealon says that Pfizer faces a net loss in cardiovascular revenue of $12 billion, with Sanofi-Aventis becoming the largest player in the market by 2009. Also, he noted that “the uptake of generic versions of these drugs is expected to be heavily promoted in an effort to reduce healthcare budgets and branded sales will slump accordingly”. Furthermore, “replacement drugs currently in development are unlikely to be able to fill the void left by the loss of these blockbusters,” he says.

As a consequence of these generics, future blockbusters will not be of the same scale as the current crop, Dr Nealon says. He believes that Eli Lilly and Amgen’s new once-weekly formulation Byetta LAR (exenatide) is likely to be the best performing of the drugs currently in development and is predicted to have peak sales of $3 billion in the major markets, compared with sales of Lipitor which hit $11.2 billion in 2006.

However Datamonitor says that the one disease area which will continue to grow in the cardiovascular franchise is diabetes, seeing as how the majority of the western world is “in the grips of an obesity epidemic”. A large proportion of the top 10 cardiovascular brands in 2016 will be diabetes therapies, the report claims, and “the complex nature of insulin formulations and the lack of generic competition from biosimilar versions” have safeguarded sales and margins of such products after the loss of patent protection. Also, legislation which will provide marketing authorisation for biosimilars “is currently held up in both the US Congress and Senate as vested interests delay the approval of the bills”.