Data from a two-year study funded by the US government have revealed that Roche's eye drug Lucentis (marketed by Novartis overseas) and the Swiss major's Avastin are equivalent in treating wet age-related macular degeneration, though the latter is not approved for that indication.

The USA's National Institutes of Health has financed the CATT trial, the results for which have been published in the journal Ophthalmology, which compared Avastin (bevacizumab) and Lucentis (ranibizumab) head-to-head for wet AMD. The data shows that at two years, visual acuity with monthly treatment was slightly better than with as-needed dosing, "regardless of the drug".

Both drugs block growth of abnormal blood vessels and leakage of fluid from the vessels, but Avastin, when used off-label for wet AMD, costs only about $50 a dose, compared with about $1,950 for Lucentis. Of the two drugs, Avastin is most frequently used.

The authors of the study at the Cleveland Clinic noted that in 2010, ranibizumab accounted for nearly 10% of the entire Medicare Part B drug budget, its single largest expenditure". As the treatment of patients "continues indefinitely, the cumulative financial burden to third-party payors and patients will only increase", they add.

Commenting on the results, Paul Sieving, director of the National Eye Institute, part of the NIH, noted that "therapies for AMD require repeated treatment to prevent vision loss. Results of this clinical trial provide evidence that long-term treatment with either drug results in a robust and lasting improvement in vision. Patients and clinicians now have valuable information to base treatment decisions".

In a statement sent to the Wall Street Journal, Roche, which has never put forward Avatin for approval in wet AMD, said it believes Lucentis is the most appropriate treatment for the condition. It argues that the drugs "were designed for different purposes and may have different safety profiles when used in the eye".

Roche adds that "we specifically designed Lucentis for use in the eye and to clear quickly from the bloodstream to minimise side effects." The CATT trial revealed that serious adverse events occurred at a 40% rate for patients receiving Avastin and 32% for Lucentis.

Novartis added that the two-year data "confirms an overall significantly higher risk of serious systemic adverse events" with unlicensed Avastin versus Lucentis, while reports of arteriothrombotic events, systemic haemorrhage, congestive heart failure, venous thrombotic events, hypertension and vascular death were more frequent in Avastin-treated patients. The company also noted that as in the year one data, there were significantly more gastrointestinal disorders in patients treated with intravitreal Avastin compared to Lucentis.

Tim Wright, global head of development at Novartis Pharma, said the data "adds to the growing body of evidence suggesting that the overall risk of serious ocular and systemic side effects is higher with unlicensed intravitreal bevacizumab compared to Lucentis". However, the NIH-sponsored studies were not powered to assess differences in infrequent but serious events such as death and stroke, "which were found in previously-published large Medicare database analyses to be significantly more frequent with unlicensed Avastin".

He concluded by noting that "the apparent differential safety risk between the two medicines may be due to differences in the molecules and their commercial formulation. This underscores the importance of drug design and development with the patient and disease process in mind."

Last week, Novartis revealed it is taking the UK's National Health Service to court because it is allowing the use of Avastin in some hospitals. The company argues that the safety profile of the cancer blockbuster in the eye setting remains unproven, noting that Lucentis stays in the body for around 10 hours; Avastin hangs around for 100 days and the impact of this on patient safety is still unknown.