A study that compared a cocktail of generic drugs for rheumatoid arthritis to a combination of methotrexate and the Amgen’s blockbuster Enbrel found the low-cost alternative as effective as the high-priced biologic, according to a study published in the New England Journal of Medicine.

In the study researchers at the Department of Veterans Affairs treated rheumatoid arthritis patients who did not respond to methotrexate, a common front-line therapy. Patients in the study either received a combination of methotrexate, sulfasalazine, and hydroxychloroquine; or methotrexate and Enbrel, a tumor necrosis factor inhibitor.

The study found that therapy with the three generic medicines was as effective as the combination of methotrexate and Enbrel. Patients that failed to respond to one combination after 24 weeks were switched to the other combination. A similar number of patients were switched at 24 weeks and a similar number of patients receiving the alternative therapy responded.

The findings could have significant implication not just for Amgen, but several other drugmakers including AbbVie and Johnson & Johnson that produce TNF inhibitors that are used to treat rheumatoid arthritis. The lead author of the study told The Wall Street Journal that the average cost for the triple therapy is about $1,000 a year compared to about $25,000 for the treatment with Enbrel.

Previous studies have shown that patients that fail to respond to methotrexate alone often benefit from the addition of so-called disease-modifying antirheumatic drugs like those used in the triple therapy. Other studies have shown benefit from adding a TNF inhibitor as a treatment to patients that fail to respond to methotrexate alone. But the authors note despite the vast cost difference between the two therapeutic approaches, few studies have sought to compare one approach against the other.

“Our findings,” the authors write, “suggest that a strategy of first administering triple therapy, with a switch to etanercept–methotrexate in patients who do not have an adequate response to triple therapy, will allow a substantial percentage of patients to be treated in a more cost-effective way without adversely affecting the clinical outcomes.”