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Adverse event rates greater in first year of psoriatic arthritis treatment with systemic therapies

Overall adverse event rates were greater in the first year of treatment compared with subsequent years for all drugs used to treat patients with psoriatic arthritis.

The study included 7,282 person-years of data from 2,084 patients and 5,018 adverse events. Findings were culled from the Biobadaderm cohort, and included patients with psoriatic arthritis treated with methotrexate, cyclosporine, acitretin, etanercept (Enbrel, Amgen), infliximab (Remicade, Janssen), adalimumab (Humira, AbbVie) and ustekinumab (Stelara, Janssen).

The general trend indicated event rates were greater in the first year than in the second or third year for most of the drugs that underwent investigation. For example, overall adverse event rates were increased in cyclosporine and infliximab, with 2,212 events occurring in the former drug in the first year and 1,776 occurring in the latter. Researchers noted cyclosporine is rarely used beyond the first year.

Overall adverse events also occurred more frequently in year 1 than in year 2 in patients treated with methotrexate, acitretin, adalimumab and ustekinumab.

Serious adverse event rates were lower than overall adverse event rates, generally speaking, according to the researchers. They added that serious adverse event rates remained constant over time. Cyclosporine and infliximab also showed the greatest rates of serious adverse events in the first year.

Classic drugs demonstrated a trend toward increased abnormal lab results in the first year compared with subsequent years, while the biologic therapies maintained a steady incidence of abnormal lab results with time.

The researchers suggested that increased reporting of events by patients may have been a type of information bias that impacted the results. Also, patients who experience events in the first year may terminate therapy, which the researchers described as a “survivor effect” for reduced rates in years 2 or 3. Meaning, patients who remain on therapies for a longer duration may be less likely to experience an event.

“Our findings provide evidence for planning follow-up visits that should be more intensive in the first year for all drugs,” the researchers concluded. – by Rob Volansky

Disclosures: The authors report associations with many device and pharmaceutical companies, including AbbVie, Amgen, Celgene, Centocor, Janssen, Eli Lilly, MSD, Novartis, and Pfizer. Please see the study for the full list of all other authors’ relevant financial disclosures.