Sanofi's Irbesartan Outperforms Losartan

Sanofi/Bristol-Myers Squibb's angiotensin II receptor antagonistirbesartan is significantly more effective than Merck & Co's losartan in lowering blood pressure in patients with mild-to-moderate hypertension, according to data from a 567-patient study presented at the American Heart Association meeting.

After eight weeks, reductions in seated diastolic and systolic blood pressures were greater with irbesartan 300mg than with losartan (both the maximum recommended doses). The reductions were respectively 3.1mmHg and 5.1mmHg greater with irbesartan, said Sanofi. A 5mmHg drop in diastolic pressure is thought to translate into a reduction in the risk of stroke and coronary heart disease in the order of 20%-30%, according to Morris Brown, professor of clinical pharmacology at Addenbrooke's Hospital in Cambridge, UK.

The difference between the two drugs may be explained by the fact that, unlike losartan, irbesartan is not a prodrug, and has a much greater bioavailability and a longer half-life than losartan.