New Drugs Show Potential in Benefiting Psoriatic Arthritis Patients

Clinical studies that evaluated two new drugs, tofacitinib and guselkumab, for the treatment of psoriatic arthritis, were presented at the Annual European Congress of Rheumatology (EULAR) 2017. Psoriasis is a condition that arises from a problem with the immune system. This involves an inflammatory process that causes thickening of the skin, resulting in large patches that are often not very easy to treat. It can also affect joints, resulting in psoriatic arthritis. The condition causes pain and swelling in the joints, referred to as psoriatic arthritis, ultimately resulting in joint damage.

The treatment of psoriatic arthritis has seen several advances in recent years. The currently available medications for psoriatic arthritis include non-steroidal painkillers to relieve symptoms, synthetic disease-modifying drugs (DMARDs) like methotrexate and leflunomide, biological agents like adalimumab (a TNFα blocker), ustekinumab and secukinumab, and corticosteroids, which are injected into the affected joints.

The two studies evaluated the use of the drugs, tofacitinib and guselkumab, for the treatment of psoriatic arthritis. While the study evaluating tofacitinib was a phase 3 clinical trial and evaluated the drug in a large number of patients, guselkumab was a phase 2 clinical trial, which evaluated the drug in a smaller number of patients.

Tofacitinib, an oral medication, had earlier received approval for the treatment of rheumatoid arthritis. It is an anti-inflammatory drug that belongs to a group called janus kinase inhibitors.

The study evaluated tofacitinib in 422 patients with active psoriatic arthritis. These patients:

• Were suffering from psoriatic arthritis for a minimum period of 6 months
• Did not respond well to at least one conventional synthetic DMARD
• Did not previously receive anti-TNFα treatment
• Were mostly Caucasians, and about half of them were female

The patients received either 5 or 10 mg of tofacitinib, adalimumab or placebo for a duration of one year.

The researchers found that:

• Tofacitinib was more effective than placebo in the treatment of psoriatic arthritis. The benefits of the treatment were noted, as early as 2 weeks, and continued for a year.
• In around 90% individuals, the disease did not progress in 1 year, as demonstrated through radiological tests.
• The side effects were similar to those noted in previous studies and included upper respiratory tract infection and headache.

The second study evaluated the use of guselkumab, a monoclonal antibody, in 149 patients with psoriatic arthritis. Monoclonal antibodies are proteins produced in the laboratory that show a specific effect against a particular disease. The patients

• Also had 3% of their body surface area affected with psoriasis
• Had received the usual prescribed treatments, which may have included anti-TNFα agents.

Guselkumab was administered at a dose of 100 mg through a subcutaneous injection, which is administered just under the skin. The injection was administered at the start of the study, at week 4, and then every 8 weekly till week 44. The researchers found that guselkumab, as compared to placebo:

• Improved outcomes in psoriatic arthritis at week 24 of treatment. Some patients experienced the benefits as early as 4 weeks of treatment
• Improved enthesitis. Enthesitis refers to inflammation of the sites where the tendons or ligaments are attached to the bones. It stimulates bone formation at these sites, and can be painful
• Improved dactylitis, a condition where the fingers and toes are affected
• Reduced the disease activity and improved quality of life
• Caused side effects that were expected and included infection. One patient had a knee injury and another had a heart attack

Further clinical trials on these two medications could see them joining the list of drugs used for the treatment of psoriatic arthritis.

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References:

1. Mease PJ et al. Efficacy and Safety of Tofacitinib, an oral Janus Kinase Inhibitor, or Adalimumab in Patients with Active Psoriatic Arthritis and an Inadequate Response to Conventional Synthetic Disease-Modifying Antirheumatic Drugs (CSDMARDS): A Randomized, Placebo-controlled, Phase 3 Trial. Abstract No. OP0216 EULAR 2017. DOI: 10.1136/annrheumdis-2017-eular.1416
2. Deodhar A et al. Efficacy and Safety Results of Guselkumab, an anti-IL23 Monoclonal Antibody, in Patients with Active Psoriatic Arthritis over 24 weeks: A Phase 2A, Randomized, Double-Blind, Placebo-Controlled Study. Abstract No. OP0218 EULAR 2017. DOI: 10.1136/annrheumdis-2017-eular.1164

Source-Medindia