(RxWiki News) If you hear about a treatment causing blindness, you're likely to opt for another one — even if it costs you much more. But in the case of two eye injections, a reported blindness risk might have been overblown.
A new study looked at two treatments for eye issues like macular degeneration and found that despite concerns, and despite drastic price differences, both were tied to similar, low rates of endophthalmitis, a serious eye infection that can cause blindness.
"Little evidence beyond highly publicized case reports exists for or against the need for additional regulation of compounded bevacizumab," explained the authors of this study, led by Brian L. VanderBeek, MD, MPH, of the University of Pennsylvania Perelman School of Medicine in Philadelphia.
These researchers noted that news stories of endophthalmitis cases and blindness after receiving the drug got a lot of attention and caused much concern.
To study this issue, Dr. VanderBeek and team compared the risk of endophthalmitis in patients who received eye injections of bevacizumab (sold under brand name Avastin) from a compounding pharmacy and those who received ranibizumab (Lucentis) injections unaltered from the manufacturer.
At compounding pharmacies, drugs can be changed or combined to be personalized for patients. According to a news release from Penn Medicine, bevacizumab is sold mainly as a cancer drug but repurposed by compounding pharmacies for smaller doses to be used in the eyes, at around $50 per eye injection. By comparison, ranibizumab comes in a form produced specifically for the eye and available straight from the manufacturer. It can cost up to $2,000 per eye injection.
Dr. VanderBeek and colleagues explained that the US Food and Drug Administration has proposed new guidelines on compounded medications that could limit the availability of bevacizumab.
These researchers looked at data from the Clinformatics Data Mart Database, a large database of insurance claims, from the start of 2005 through the end of 2012. A total of 383,810 injections of the two drugs among 58,612 patients were analyzed. Patients who had a history of endophthalmitis were not included in this study.
Both drugs were tied to very low rates of endophthalmitis, Dr. VanderBeek and team found. Among the 269,565 bevacizumab injections given to 51,116 patients, a total of 49 cases of endophthalmitis were reported — a rate of 0.017 percent of injections. Among the 87,245 ranibizumab injections given to 7,496 patients, 22 cases of endophthalmitis were reported — a rate of 0.025 percent.
"The results of this study suggest bevacizumab as currently used across the United States does not increase the risk for endophthalmitis; therefore, additional regulations on the use of repackaged bevacizumab may be unnecessary," Dr. VanderBeek and team wrote.
Because this study looked at medical records data and depended on the use of medical codes, some data and details might not be complete, Dr. VanderBeek and team noted.
This study was published online Aug. 13 in JAMA Ophthalmology. A number of groups funded this research, such as the National Institutes of Health and the Paul and Evanina Mackall Foundation. Dr. VanderBeek and team disclosed no conflicts of interest.