Thursday, March 27, 2008

Avastin/Lucentis Update 22: Recent Avastin Study Compared to Use of Lucentis in PrONTO

Dr. James Folk, writing in his Medical Rounds Blog, commented on a recent study done by Bashshur and colleagues and published in the American Journal of Ophthalmology. In the Bashshur study, the doctor and his colleagues treated 60 patients with Avastin only, but at a higher than normal dosage – 2.5 mg vs 1.25 mg. They gave one injection and then observed the results one month later using OCT.

If the OCT was dry, the authors didn’t give an injection but asked the patient to return one month later for a re-examination. The treatment paradigm was similar to the PrONTO study except in PrONTO, Lucentis at 0.5mg was used instead of Avastin and the patient first received three monthly injections followed by additional injections as needed.

The other difference was that Bashshur and colleagues would not reinject if the eye showed persistent subretinal or intraretinal fluid after three injections. They believe that these eyes often remain stable. Therefore they would follow them and only reinject if they worsened. In the PrONTO study, any fluid on OCT was an indication for another injection.

As Dr. Folk noted, the Bashshur study was small, only 60 patients (with 9 lost to followup), but the Comparison of AMD Treatment Trials (CATT) is starting and will be the definitive study comparing Avastin to Lucentis for the treatment of wet AMD. The results of Bashshur and colleagues however predict that at most, we’ll probably only find a modest difference between the two drugs.