Comparing Rx for Psoriatic Arthritis

Psoriatic arthritis medication adalimumab came out ahead in efficacy and cost comparison

(RxWiki News) Three medicines are most commonly used to treat psoriatic arthritis. But is one better than the others?

Researchers put together data from trials that used adalimumab, etanercept and infliximab. After six months of treatment, about three times as many people taking adalimumab showed a 70 percent improvement in symptoms compared to those taking etanercept.  Infliximab and adalimumab helped about the same number of people to reach a 70 percent improvement.

"Ask your doctor which psoriatic arthritis medicine is right for you."

Abbott Laboratories, the maker of Humira (adalimumab), asked the Analysis Group to do a comparison between their medication and other treatment options for psoriatic arthritis.

The study, led by Kirson Y. Noam, PhD, of the Analysis Group, used data from a trial of adalimumab and put it together with info from trials of etanercept (sold as Enbrel) and infliximab (sold as Remicade). A total of 701 patients were included.

The trials measured improvement of symptoms using the American College of Rheumatology (ACR) criteria. ACR looks for improvement in sore or swollen joints, overall pain rating and level of disability due to arthritis.

ACR70 means that people reached 70 percent improvement according to the ACR scale. In this study, the researchers wanted to see which patients being treated for psoriatic arthritis reached this level of improvement.

More people taking adalimumab (32.9 percent) than people taking infliximab (14 percent) reached ACR70 after 14 weeks of treatment. However, after six months of treatment, both medicines helped about the same number of people reach ACR70 (35 percent and 25 percent).

There were no differences between adalimumab and etanercept in the number of people reaching ACR70 after 14 weeks of treatment. After six months, more people taking adalimumab (23.9 percent) than people taking infliximab (7.9 percent) reached ACR70.

The study also compared the estimated costs of each of these medicines for people who reached ACR70. People taking etanercept who reached ACR70 after six months of treatment spent about $200 more on their total treatment than those taking adalimumab who reached ACR70.

People taking infliximab who reached ACR70 after six months of treatment spent about $4,000 more on their treatments than those taking adalimumab who reached ACR70.

The authors concluded that adalimumab was better than etanercept for helping people reach ACR70. Adalimumab was similar to infliximab in terms of treatment, but much cheaper for the patient.

This study was limited by the fact that it was not a direct comparison of the three medications. The researchers only looked at the responses to these medications in separate trials, which means there could have been differences between the trials that affected the outcomes for certain patients. A head-to-head, placebo-controlled trial is needed.

Also, fairly low numbers of patients taking any of the medications reached ACR70 (less than half for all the medications). Why these medications are helpful for some and not for others was not addressed by this study.

Humira costs about $2,000 per month for injections. It is not available in generic form. Enbrel costs about $2,400 to $3,000 per month and is not available in generic form. Remicade costs about $1,300 to $2,000 per month.

Trexall (methotrexate), another medication for psoriatic arthritis not included in this study, is about $220 a month in brand name form or $12 per month in generic form.

The study was published January 22 in the Journal of Medical Economics. The study was funded by Abbott Laboratories.

Review Date: 
January 29, 2013