Patients with Psoriatic Arthritis Tend to Quickly Modify or Abandon Initial Treatment

The majority of patients with psoriatic arthritis treated with disease-modifying antirheumatic drugs (DMARDs) will switch medications, discontinue treatment, or add an additional medicine, usually within a few months of initiating treatment.

To gain a better understanding of how often patients alter their therapy, the authors of “Treatment Patterns in Psoriatic Arthritis Patients Newly Initiated on Oral Nonbiologic or Biologic Disease-Modifying Antirheumatic Drugs,” published in Arthritis Research & Therapy, the authors conducted a retrospective study of treatment patterns using data from the US-based Truven Health Analytics MarketScan Research Database for adult patients with psoriatic arthritis who initiated treatment with oral nonbiologic DMARDs or biologic DMARDs. All participants had continuous insurance coverage for at least six months prior to starting treatment, and for at least 12 months after their first prescription fill date.

For the study, 1,698 patients initiated treatment with an oral nonbiologic DMARD and 3,263 patients were initiated on a biologic DMARD. The majority of patients initiating with a nonbiologic DMARD were prescribed methotrexate (71%, n = 1,217).

Other oral nonbiologic DMARDs used included cyclosporine, leflunomide, mycophenolate, gold compounds, antimalarials, minocycline, penicillamine, azathioprine, and sulfasalazine.

Biologic DMARDs in the study included etanercept, infliximab, golimumab, certolizumab pegol, adalimumab, anakinra, abatacept, and rituximab.

When analyzing treatment events and patterns, the authors defined therapy change as “the discontinuation of the index treatment (that is, the nonbiologic or biologic DMARD initiated at the index date), a switch from the index treatment to another treatment, or a therapy add-on.”

Treatment discontinuation was defined as “the first occurrence of a treatment interruption of at least 60 consecutive days between the end of the drug supply for a prescription of the index treatment and the beginning of a next prescription for the index treatment, or the end of the one-year study period, whichever occurred first.”

Treatment switch was defined as “the initiation of a treatment other than the index DMARD within 60 days of the interruption of the index treatment.” Therapy add-on was defined as “the use of a DMARD treatment other than the treatment used at the index date for at least 28 consecutive days before the discontinuation of the index therapy.”

The authors reported that 69% of patients initiated on an oral nonbiologic DMARD had at least one therapy change during the 12-month study period (including 65% of the patients initiated with methotrexate). The median time to the first therapy change was 85 days for patients initiated on an oral nonbiologic DMARD (93 days for methotrexate patients).

Among nonbiologic DMARD users who had at least one therapy change, 83% discontinued treatment (median time: 89 days), 29% switched (median time: 113 days), and 25% had a therapy add-on (median time: 116 days).

Forty-six percent (46%) of patients initiated on a biologic DMARD had at least one therapy change during the 12-month study period. Median time to first therapy change for this group was 110 days.

Among biologic DMARD users who had at least one therapy change, 100% discontinued treatment (median time: 122 days), 25% switched treatment (median time: 173 days), and 7% had a therapy add-on with a nonbiologic DMARD (median time: 59 days).

In their discussion of these results, the authors wrote that “patient persistence with treatment was generally low and relatively brief” among patients who initiated treatment with an oral nonbiologic DMARD, with most patients who switched treatment or had a therapy add-on opting for a biologic DMARD. In fact, “only 31% of the patients persisted uninterruptedly with their initial nonbiologic DMARD therapy after one year, and slightly more than half (56%) persisted uninterruptedly with any nonbiologic or biologic DMARD after one year.”

For patients who initiated treatment with a biologic DMARD, 54% persisted with their initial therapy throughout the entire 1-year study period and 70% persisted on some form of therapy. More than 90% of patients who switched therapy opted for another biologic DMARD. This, combined with the fact that only 7% of patients had a therapy add-on with a nonbiologic DMARD, suggests that “patients initiated on a biologic DMARD tend to remain on this form of therapy and do not switch back to nonbiologic DMARDs.”

Potential reasons for therapy change from initial treatment suggested by the authors include lack of effectiveness at controlling patient symptoms and slowing disease progression, tolerability or safety issues, adverse events, and insurance-related factors (for example, the authors noted that many plans require patients to first use at least one to two nonbiologic DMARDs prior to using a biologic DMARD).

The authors conclude that the results “suggest that the majority of patients treated with nonbiologic or biologic DMARDs change therapy early after treatment initiation, with many switching to a biologic DMARD therapy or, in nonbiologic users, adding on a biologic DMARD. Among the initial biologic DMARD patients who end up switching therapies, the majority do so with another biologic DMARD (as opposed to a non-biologic DMARD).”