NEPHRIC conclusion: “… the likelihood that contrast medium-induced nephropathy will develop in high-risk patients appears to be significantly reduced when [Visipaque] is used rather than a low-osmolar non-ionic contrast medium [iohexol].”

In February 2003, a landmark clinical study was published in the prestigious New England Journal of Medicine. The NEPHRIC study¹ showed that high-risk patients who received Amersham’s third-generation, non-ionic X-ray contrast agent, Visipaque, were 11 times less likely to develop contrast-induced nephropathy (impairment of kidney function) than patients who received the leading second-generation, non-ionic product, iohexol. The response to this study by doctors was immediate and overwhelming. In the first half of 2003, global sales of Visipaque increased by 32 per cent^* compared to a year earlier, with impressive growth in all main geographical regions.

The patients in this study had diabetes and existing kidney problems, and were being investigated for cardiac and vascular disease. Patients with diabetes and impaired kidney function are at increased risk of developing further kidney impairment, or in the worst case, acute kidney failure, from the X-ray contrast agents used in medical scanning procedures. This serious complication is the number one safety concern of physicians in this group of patients.

In the general population, the incidence of contrast-induced kidney impairment is less than two per cent. For patients with diabetes and existing renal impairment, the risk is significantly higher – and the number of patients in this high-risk category is growing, due to the increased incidence of lifestyle-related diabetes and the ageing population.

That is why the NEPHRIC study is so important. It showed that the incidence of impairment of kidney function was only three per cent when Visipaque was used, compared with 26 per cent in the patients given the comparator contrast agent, iohexol.

Just why X-ray contrast media affect kidney function is not clearly understood. However, medical literature suggests several factors could be involved, and indicates that osmolality, or the concentration of particles in solution in the contrast agent as opposed to the blood, may be one of the key factors in high-risk patients. And this is where Visipaque differs from other products in the market. Visipaque is isosmolar, which means that its osmolality is equal to that of the blood in all product formulations.

Other non-ionic products, although they are known as low osmolar contrast agents, have particle concentrations that are two to three times higher than the blood.

The NEPHRIC study adds important clinical data on the potential beneficial effect of using Visipaque in patients at risk for contrastinduced nephropathy. Amersham will continue to invest in this brand by conducting additional clinical studies on the effect of Visipaque on renal function.

Amersham Health is a global leader in medical diagnostics, with an estimated world market share of 38 per cent. We provide injectable pharmaceuticals used in medical scanning procedures to enhance the image of soft body tissues. Our products enable early, accurate diagnosis and management of heart disease, circulatory disorders, brain disease and cancer.

¹ P Aspelin et al., N Engl J Med 2003; 348: 491-9
^* At constant exchange rates