The US Food and Drug Administration is looking into cases of serious eye infections in patients who have been treated with Avastin, Roche's blockbuster which is often prescribed off-label to treat wet age-related macular degeneration.

The agency is alerting healthcare professionals that repackaged intravitreal injections of Avastin (bevacizumab) "have caused a cluster of serious eye infections" in Miami, and investigators traced the tainted injections to a single pharmacy. The latter then distributed the Avastin to multiple eye clinics.  

To date, FDA is aware of at least 12 patients in at least three of these clinics who had Streptococcus endophthalmitis eye infection. While all of them "had visual deficits prior to their injections with Avastin, some of these patients lost all remaining vision in that eye due to the endophthalmitis", the agency said. There have also been reports of four patients in Tennessee who were injected with Avastin that was supposedly contaminated by bacteria.

The FDA warnings add to the controversy of using Avastin off-label for the treatment of wet AMD, rather than an approved drug Roche's own Lucentis (ranibizumab). Doctors have been using the cancer blockbuster because it is a fraction of the cost (around $50 per injection) of Lucentis (some $2,000).

Roche's Genentech unit has regularly warned about using Avastin off-label and in 2008 highlighted 36 reports of intraocular adverse events, 32 of which involve serious inflammatory reactions, all originating in Canada. A year earlier, Genentech had said that Avastin would no longer be supplied to independent compounding pharmacies that divide vials so that ophthalmologists can use it to treat AMD, though a deal with doctors was struck later.