Patients Develop Resistance to Popular RA Drug, Study

April 13, 2011

Humira was found to be ineffective on twenty-eight percent of RA patients in a recent study

Humira, the top-selling rheumatoid arthritis (RA) drug of Abbott Laboratories (ABT), was found to be ineffective on twenty-eight percent of patients in a recent study.

The three-year study was published in the Journal of the American Medical Association. It was performed on 272 patients taking Humira, and of that number, twenty-eight percent of those patients developed antibodies which lowered the drug’s levels in the blood.

“These results could have implications for clinical practice,” said the researchers, led by Geertje Bartelds of the Jan van Breemen Research Institute in Amsterdam. “Adjusting policy could lead to more cost-effective treatment” since patients possessing the antibodies “had a higher disease activity and rarely achieved remission.”

The antibody group was significantly less likely to continue with the treatment than patients without these antibodies; they were also less likely to experience relief from the disease symptoms or to enter remission.

Of the seventy-six participants who developed resistance to Humira, (also known as adalimumab) sixty-three percent ceased using the drug due to the failure of the treatment, side effects, or undisclosed factors; of the 196 without the antibodies, only thirty-nine percent ceased using the drug.

Further, merely thirteen percent of the antibody group attained “minimal disease activity,” in comparison to the forty-eight percent in the non-antibody group, and only four percent were in “sustained remission,” verses the thirty-four percent of non-antibody participants.

According to the study, sixty-seven percent of the patients who developed the antibodies and, therefore, a resistance to Humira, did so inside of the first twenty-eight weeks of treatment.

While it was not made explicitly clear as to why some patients became resistant and others did not, researchers said that genetics could play a role. They also reported the possibility of lessening the antibodies with other drugs which suppress the immune system.