Genentech may have innovated itself into a corner. A study published in the journal Ophthalmology compared the impact of its age-related macular degeneration drug, Lucentis (ranibizumab), to its cancer drug, Avastin (bevacizumab), and found them equally effective. Age-related macular degeneration, or AMD, is caused by an abnormal growth of blood vessels in the eye, triggering an accumulation of fluid and blood that damages the retina, and Avastin has been prescribed off-label to treat the disease.

The finding could put the Roche subsidiary in a bind, because Lucentis costs $1,950 per dose, while Avastin is priced at around $50. The disparity affects more than just Genentech: Novartis sells the AMD drug abroad and is currently suing Britain’s health authority to stop using the drugs interchangeably.The study treated patients using identical forms of vision measurement as the basis of treatment. The Lucentis patients were treated with 0.5mg of the drug, while Avastin patients were given 1.25mg.

Yet these results are not the only reason Genentech could be on edge — the FDA approved Regeneron’s wet AMD drug, Eylea, in November. Leerink Swann analyst Seamus Fernandez found the drug so compelling that he dropped his Lucentis sales forecast by $1 billion.

The Lucentis-Avastin Ophthalmology article is a follow-on to a one-year study held in 2011 that showed the two drugs helped patients equally; the latest results show that this data holds even over a two-year period. The authors noted that Avastin did have more serious adverse reactions than Lucentis and that Lucentis reduced the amount of excess fluid more frequently than Avastin. It also notes that Lucentis prescriptions took up almost 10% of the Medicare Part B drug budget, the plan’s single largest expense. They also note that treatment is perpetual, so payers will have to continue to fund treatment. The National Institutes of Health says AMD is the leading cause of vision loss and blindness in among adults.