Phase III Trial Results Show Certolizumab Pegol Is an Effective Treatment for Psoriatic Arthritis

Patients with psoriatic arthritis treated with certolizumab pegol (CZP), a PEGylated Fc-free anti-tumor necrosis factor (TNF), showed “rapid improvement” in symptoms related to joints, skin, enthesitis, dactylitis and nails, according to a phase 3 study published in the Annals of the Rheumatic Diseases.

For the double-blind, controlled study, Philip J. Mease, MD, from the Swedish Medical Center and University of Washington in Seattle and his research team randomized 409 participants to receive one of two doses of CZP and compared results to a placebo group.

The study authors reported, “ACR20 response was significantly greater in CZP 200 mg Q2W and 400 mg Q4W-treated patients than placebo (58.0% and 51.9% vs 24.3% (p<0.001)) at week 12, with improvements observed by week 1.”

In total, 368 participants completed the study. By week 24, researchers observed more patients with improvement in both medication groups (CZP 200 mg and CZP 400 mg) compared to placebo, (78.3% and 77.0% vs 33.1% (p<0.001).

A significant number of study participants (70%) used combined doses of DMARDs with CZP. About 20% of both groups (placebo and combined dosages) used TNF inhibitors at some point before the study.

Mease said “the ACR responses were the same regardless of whether the patient had been previously anti-TNF-exposed.” Interestingly, many people on TNF inhibitors will eventually show decreased response rates to treatment.

“Recent studies of ustekinumab (an interleukin 12/23 inhibitor) have demonstrated this expected reduced efficacy in PsA patients with prior exposure to TNF inhibitors,” according to study authors. And for this reason, in the past, a course of TNFs would have disqualified them from study participation—until now.

Mease said this study is unique because it included people with prior anti-TNF treatment regimens—something that helped researchers fully observe treatment outcomes among patients with PsA.

“Knowing that the ACR responses in the CZP PsA study were similar in patients who had been on prior TNF inhibitor therapy gives you some confidence that in a patient who is on an anti TNF medication and is not responding adequately, then it would be reasonable to consider trying certolizumab,” said Mease.

That’s an important point considering that a fair number of people eventually stop responding to medications and will likely need other treatments. Plus, with fewer available treatments for PsA and the high prescription costs that make it hard for patients to afford them, researchers pointed out that physicians may need to “cycle through TNF inhibitors” if DMARDs stop working.

A look at CZP safety

Less serious common side effects included diarrhea and headache‑‑3.6% CZP vs. 2.9% placebo, and 3.6% CZP vs. 1.5% placebo, respectively.

Commonly reported infectious adverse effects were nasopharyngitis and upper respiratory tract infections, at 3.6% CZP vs. 1.5% placebo; and 7.8% CZP vs. 5.1% placebo, respectively. Participants reported their symptoms as mild to moderate. In essence, at week 24, respiratory problems were reported in 21 people in the placebo group, and 38 people in both CZP dosage groups.

Also of note, researchers found that participants in the CZP groups more often showed elevated liver enzymes, compared to placebo group.

With more research in the pipeline, physicians are hopeful that new treatments for people with PsA will become available. “There are fewer options for PsA patients, with approved drugs, compared to rheumatoid arthritis,” said Mease.